# JBL MS-8 FAQ



## Tendean17

DIYMA.. This is my first Thread. 










Bikinpunk says "_If you love car audio tuning but really hate or just do not know how, then this processor is for you. The MS-8 does in 5 minutes What would take me a couple months of hard work to do. Then throw in the added benefits of great sound at different seats and I've just added many more months onto my manual tune_" 

I love car audio and I'm not the lazy guy. I've tried hard but still could not make me happy in my car. Maybe i just do not know how to tune it well and there is no comparison that i can do here. There is hardly any installer who has competence in the small town where i live. 

I find it difficult to find the posted articles of this processor because they are included in several threads. Require several weeks to collect, read and know about the processor further. Select from the thousands of posts and to make me easy then I just copy and paste the article into almost 100 pages of Word Document. Then i just print the document and i can read it in my spare time .. then I thought "Why not i just share my documentation ?" That’s why i make this thread.

I documented the complete enough and i think is useful also for other friends in this forum. After all the material collected so i separate them into categories that make me easy to read. This classification is not 100% accurate because sometimes what the experts say covering into several categories. 

In case someone interest can PM me your email address and i will send to you. If you feel useless .. easy .. just remove from your computer. I live 180 degrees Out of Phase with almost all of you my friends .. so i need maybe 1 or 2 days to send it to you. I do not have the JBL MS-8 but i have planned about it. 

Hopefully useful .. Sorry for my english and this is not my review.


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## Tendean17

JBL MS-8 - Categories :
*
•	About JBL MS-8 
•	Prepare your system design first 
•	Target Curve for JBL MS-8 
•	Phase Frequency Response 
•	Center and Rear Channel 
•	Aux Input, Signal Level and Preout Voltage 
•	Measurement and Setup 
•	System Noise 
•	Happy Customer 
•	Feature Request *

Here's the Links ... 

*JBL MS-8 - FAQ ( This Thread )* 
http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/98699-jbl-ms-8-faq.html

*JBL's MS-8 ( bikinpunk Review )*
http://www.diymobileaudio.com/forum/product-reviews-erin-harrdison-bikinpunk/83066-jbls-ms-8-a.html

*JBL MS-8 Impressions ( npdang Review )*
http://www.diymobileaudio.com/forum/member-reviews-product-comparisons/84287-jbl-ms-8-impressions.html

http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/87168-please-post-your-ms-8-system-layout.html

http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/95061-ms-8-display-unit-where-you-guys-mounting-yours-pics.html

http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/85136-ms-8-tips-tricks-thread.html

http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/95994-ms-8-setups.html

http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/95986-ms8-what-if-center-channel-larger-driver-than-midbass.html

http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/97906-ms-8-phase-question.html

http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/98080-jbl-ms-8-install-question-andy.html

http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/96152-ms-8-8-v-preouts.html

http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/97804-ms-8-custom-settings-question.html

http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/98016-ms-8-says-level-low-stock-g37-headunit-linedriver.html

http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/84112-jbl-ms8-horns.html

http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/85935-jbl-ms-8-feature-request-thread.html

http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/96919-ms-8-t-crossover-questions-gurus.html

http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/95771-why-heck-isnt-jbl-ms-8-controlled-via-iphone-ipad-android.html

http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/94547-should-i-get-jbl-ms-8-sound-processor-2.html

http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/94530-jbl-ms-8-internal-amp.html

http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/88937-ms8-problem-no-audio-calibration-disc-help.html

http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/83161-dex-p99rs-jbls-ms-8-processor.html

http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/92051-how-much-you-liking-your-ms8.html

http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/8257-jbls-ms-8-processor.html

Other topics ..

http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/97723-adjusting-phase-around-crossover-frequency.html

http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/97851-generic-question-regarding-center-channels.html

http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/11579-flat-response.html

http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/97677-jbl-ms-2-a.html


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## Tendean17

*About JBL MS-8
*
300Z :

MS-8 comes with the pre-amp/amp, a small display, a wireless remote control, a binaural microphone and a setup CD.

MS-8 will have 8 speaker level inputs, 8 line level inputs and an iPod input. The inputs are summed to provide a full-range 2-channel signal. If 6 or fewer inputs are required, then the last 2 can be used for an additional aux input.

There are no digital inputs. Why? Because the real benefit of digital input is "no noise". The downside to providing one is that for 99 percent of users, it's more hassle than it's worth and will cause a great deal of confusion. Not too many people understand that the connector doesn't determine the signal. What I mean is, if we put a toslink input and a user hooks up a toslink output, it will only work is the signal is compatible. DVD-Audio isn't available on a digital output, DVD signals are 48k, PCM is 44.1, home-made digital audio can be anything. The signal from tuners is often only output on the RCAs. For the vast majority of users, there is no benefit and too much opportunity for disappointment. As far as noise goes, our inputs are differential, so the common mode noise rejection is super high. There won't be any noise.

There are 8 input channels, so the 8 speaker level inputs and 8 line level inputs are basically in parallel. You can use any combination.

Once the signals have been combined and un-EQed (for a flat 2-channel signal), the signal is processed with Logic7. That provides signal steering for a center channel (if you have one--if not, no problem) and processing for side and rear channels. L7 works on any 2-channel source and is our version is written for cars rather than live-in rooms, so it sounds MUCH better than any of the encoded formats in a car. The 2-channel downmix of any encoded DVD or DVD-A disc will play back in full surround. If good-old 2-channel is what you want, L7 is defeatable and the channels are fully configurable (there are 8 output channels and they can be pre-amp channels or powered channels--20W x 8 at 4 ohms, 30W at 2 ohms). You can have 3-way front, a center and a sub, 2-way front, rear and a sub...whatever you want to do.

The electronic crossover that's built in is fully configurable. You can assign any channel to be anything and it includes an EZ setup mode and an advanced mode. In EZ setup, you tell each channel the speaker location (front right, for example), then you tell it what speaker is connected (6" full-range). It sets the crossover point. In advanced mode, you tell the channel the location (right front) and then assign a filter type (HP, LP, BP) and then you set the filter frequency (you can assign any value between 20 at 20kHz) and the slope (1st-4th order).

After the crossover setup is completed, you move on to the EQ. You put on the microphones (they look like airline headphones but contain mics instead of speakers) and insert the CD. The display will give you some instructions to sit in the driver's seat and look at the left mirror and press "go". the unit will make a quick sweep of all 8 output channels. Then it will ask you to look forward and will make another sweep. Finally, it'll ask you to look to the right--another quick sweep. You can measure only the driver's seat or up to 4 seats. After the measurements are made (takes about 5 minutes) the unit will calculate the frequency response, level and arrival time for all 8 channels in each seat and crunch some numbers (another 30 seconds or so). It auto-tunes the car with 48 measurements per seat (up to 4 seats). It will output a tuning optimized for the driver, passenger, compromise between driver and passenger and one for the rear seats. If you use a center channel, both front seats will sound the same and the image will be great for rear seat passengers too.

After the auto-tuning is done, it will allow you to change the target curve. You can call up a 31-band EQ tool and make whatever changes you want. Unlike a regular EQ, you don't have to find an RTA and tune the car with the EQ, you just draw the curve you want to hear and press "go" and it does the work in implementing your curve. Then you can switch back and forth between your curve and the automatic one and continue making changes until you're satisfied. The curve you draw will always be adjusted in level so that the maximum number of bits are available to describe the signal (optimized for dynamic range). Once you save the curve, you can access any of the settings optimized for any seat using the remote control and the display.

You can turn Logic7 on and off, adjust the level of the center channel, use a balance control, fader, 3 or 11-band graphic EQ or adjust the level of the bass. THe bass control isn't a gain control for the subwoofer output, it's a filter that works with the crossover and applies the right amount of bass to ALL channels so the illusion of bass up front isn't destroyed when you turn up the bass.

Answers to some likely questions:

1. You don't have to use the unit's volume control. You can use the one in the head-unit if you want to.
2. Maximum input voltage on the RCAs is 2V and 15V on the speaker level inputs. The signal is converted directly into digital after the preamp buffer, so a high signal level is far less important in this device than in conventional ones. The input is fully differential, so there won't be noise. I suggest speaker level connections because they are COMPLETELY isolated from ground.
3. The automatic EQ isn't exactly parametric or graphic. It's a very powerful algorithm that works on the impulse response to adjust both time and frequency response. It's amazing and does in about 30 seconds what I can do with an 80 band parametric EQ, crossover, time alignment and a serious analyzer in about 3 days.
4. The display doesn't have to be mounted. If you don't want iPod control or the ability to adjust after setup, you can unplug the display and use MS-8 as a "black box".
5. The unit is small--about 8.5" x 11" x 2.5"
6. Price will be about $800...TBD
7. The software is updatable via USB and a PC.

It does what all other OEM integration tools do and what every other DSP (EQ, Crossover, Time alignment, 7.1) processors do, but it sounds better, is easier to use, is less expensive and is far more advanced in terms of DSP power. Best of all, it's a tool you can be successful with, rather than a whiz-bang collection of filters and adjustment possibilities that require a PhD in acousitcs to use.


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## Tendean17

t3sn4f2 :

Andy from Harman giving more details on the MS-8 and comparing it with the PXE-H650.
From Audiogroupforum.com

"There are lots of differences. First, MS-8 is more expensive.
Some technical differences are:
1. MS-8 includes power for speakers.
2. MS-8 includes a center channel output and a matrix surround processor (Logic7), which is more about fixing the image for the passengers than about reproducing an audio equivalent to a roller-coaster ride. The Apine doesn't include a center output and doesn't include that image processing.
3. The MS-8's crossover is fully configurable. It'll support any system of 8 channels or fewer, including 7.1, 5.1, 3.1, or the standard car-audio 2-channel bi-amped or tri-amped front stage and a sub. anything is possible, since all the channels can be anything, but crossover setup is manual in MS-8. It's automatic in the Alpine, but it's less configurable. The outputs are fixed.
4. MS-8 includes an auxiliary input and a remote control and display which allows you to make some adjustments after setup and includs a volume control for those pesky OE systems that include dynamic "bass elimination" (many GM).
5. MS-8's subwoofer level control is a shelf that's applied to all the channels through the crossover and the bass management algorithm. It'll preserve the impact in the front of the car AND add bass.
6. The automatic equalizers are completely different. The Alpine uses a 512-tap filter, which also equalizes phase and sets time alignment. It also includes some spatial averaging for multiple microphone placements (6). When you equalize with the Alipine, the first microphone placement sets the time alignment and the rest of the placements are used to smooth the frequency response over most of the car's interior. Multitap filters that operate in real time are a relatively new possibility. In years past, multitap filters in real time were only a hope, since there weren't many microprocessors that could process all that information quickly enough. The benefits of usiing a multitap filter are that they can be very precise and they equalize phase as well as magnitude since they operate on the impulse response measurement. For one tiny point in space, they can also eliminate the sound of plenty of reflections, but their ability to do that accurately diminishes in larger listening areas, since the effects of reflections at high frequencies can be very different even a few inches away from the original microphone position. The other important thing to note about multitap filters is that the 512 "bands" are distributed in a linear fashion rather than logarithmically. That means the resolution is fixed across the audio band. 512 taps gives you roughly 40 Hz resolution. That means you get 2 adjustment bands between 20 and 100Hz and 25 bands between 10k and 20k. Multitap filters, by default place more adjustment possibilities in the high frequencies than in the low frequencies because of the linear distribution of those "bands". That's the only drawback. The Alipine allows you to select from several target curves for adjustment after the automatic setup.

One more note about multitap: They are the shiznit for headphone EQ, because the "listening space" is fixed. With multitap EQ, you can add the reflective properties of a completely different space and transform the listening area to a completely believable representation of a much larger space. With speakers, that isn't possible yet because both of your ears hear both speakers and moving your head helps you determine the location of sounds (just like when your dog cocks his head when he hears a sound he doesn't recognize--we do the same thing, it just doesn't look so ridiculous).

MS-8's EQ is different. We also use a spatial average, but we use a binaural measurement system and 3 mic positions PER LISTENING POSITION. That gives us 6 measurements per seat for each of the 8 channels plus a time alignment adjustment for each seat. Once the setup is done, you can choose an optimization for any seating position and switch between them. For frequency response EQ, we make standard frequency response measurements, eliminate the phase measurement, average the measurements), calculate the phase response of the average, turn the measurement into an impulse response measurement, apply 8 biquads (filters) to the impulse response according to the target curve and the crossover settings using a very complicated and sneaky algorithm that I can't divulge because we're applying for a patent. The result is a VERY powerful EQ that can be implemented on a relatively inexpensive DSP for each channel and leave plenty of space to use the same algorithm on the eletrical signal of the MS-8's input for flattening of the input signal. The distribution of the bands is logarithmic and makes a completely adjustable target curve easy to implement and accurate. Each speaker location is equalized separately and, because of the spatial average, the acoustic sum of the channels matches the target curve. Once setup is complete, you can fine tune the car using a 31-band drawing tool. You draw the curve you want to hear and the MS-8 implements it and allows you to audition your changes vs. no EQ and vs. the automatic implementation of the predefined target.

Both pieces of equipment are technological marvels and they both include input channel summing and signal conditioning, crossover and EQ). MS-8 includes more stuff (center channel, Logic7, amplifiers, a display and remote, equalization memory and multiple seat optimization, center channel output and automatic input configuration--MS-8 will figure out what you've connected to the input regardless of polarity), but it should. It's more expensive.

Which one sounds better? You'll have to be the judge.

One last note: Both of these products are super-important and may help to revive the industry and get new customers interested in making their cars sound great while preserving their factory user interfaces. They have both been long development processes with plenty of invention and innovation, software development hiccups and decisions about which features to implement. Both products will require some new thinking on the parts of installers and salespeople about how one implements great audio. Simple 2-channel audio isn't dead, but these kinds of advancements make better listening experiences possible using a new set of rules.

Kudos to Jason ad his team for beating us to market. The other difference is that MS-8 isn't quite finished yet-but it will be.
__________________
Andy Wehmeyer
Global Product Line Manager, JBL Car Audio
Harman Consumer 
______________________________________________________________

t3sn4f2 :
_Me - "Hi Andy. If I dont have a center channel, can I use Logic7 mode with a no center setting and does it then do something special to the prcoessing so that its like a phantom center setup, or do I have to go with stereo mode in that case and loose the other benefits of Logic7. Also is the auto EQ only for Logic7 mode or is it availiable for stereo mode too?"_

Andy Wehmeyer :
"T3, If you don't identify a channel as a center, Logic7 won't be completely engaged. There will be some ambience processing for the rear and the time alignment will be set for a single listening position. After setup, you can choose between optimizations for each of the 4 seats, but they won't all image simultaneously like they will if you use a center. EQ is completely separate from L7. It works no matter the setup."

t3sn4f2 :

The Main Menu is:
1 Input Selection
2 Audio Controls
3 User Presets (EQ)
4 Calibration/Setup
5 System Settings

The Audio Controls Menu is:
1 System Levels
2 Tone Control
3 Input Levels
4 Logic 7 ON/OFF
5 Controls Defeat/Active
6 Reset to default

The Tone Control will include the user-adjustable EQ.


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## Tendean17

Andy Wehmeyer :
Wow...another super long thread about MS-8.
I think most of the questions about the product have been answered here, thanks to someone pasting responses from the now almost dead carsound forum. Thanks for that. 

I agree that there haven't been many room correction algorithms that work well, but the one in MS-8 is a good one. There's a huge difference between room EQ in a room and room EQ in a car. Correcting response in a room with real speakers really requires two different kinds of measurements--a near field measurement of each speaker and a correction scheme for that and a second set of spatially averaged measurements for correcting room modes. In a car, we can combine this into one, since the seating positions are fixed and since the speakers are very close to the listeners (compared to a room). There's so little delay between direct sound and reflections (the time and magnitude) are so close that we hear them all as speakers. In rooms, it's important to differentiate between the two. 

Can a person do a better job of tuning than MS-8? I can and I'm sure there are a few others who can too, but MS-8 has been designed to make everyone's car sound better--people like my mom who love music but don't know anything about audio--and for installers to implement. I can do a better job than MS-8 but in order to do it I need lots of bands of parametric EQ (currently I have 176 biquads available for eq and crossover), time alignment, phase shifting parametric all pass filters, separate gain control of all speakers, Logic 7, a mic array and multiplexing mic preamp, an RTA with 1/24 octave resolution, an analyzer than can measure impulse responses and phase, and a couple of weeks.

MS-8 includes all these capabilities and does about 90% of the job in about 10 minutes. 
Regarding the debate between Car PC and MS-8: A car PC can include many if these tools all kludged together (except Logic 7). A car PC is like a basket full of groceries and MS-8 is like a great meal. 

Why am I building a car PC? 
1. Because i'm a glutton for punishment
2. Because the aux adapter I use from USA-SPEC screws with the CAN bus in the car and prevents the steering wheel track up and down button from working properly
3. Because I'm tired of having an iPod controller screen stuck to the top of my dash
4. Because Gary Biggs is building a new car with a MAC Mini as a head unit, asked me for help in figuring out how to configure it and he got me hooked.
5. This is the biggest reason: Our DSP engineers are constantly working on new algorithms to do this and that (top secret) and we need a way to evaluate and car-optimize them as VST plug-ins before they become embedded solutions for home audio


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## Tendean17

donkeypunch22 : 
_Andy, thanks for taking the time to answer. I needed some inspiration to keep the faith!
Oh, and Andy, if you could, what are "eight biquads of filters"? I know a filter is the same word for an eq, right? But what is a biquad?
_
Andy Wehmeyer :
Let's make this easy and say a biquad is a filter that can be configured to be a high pass of just about any alignment; low pass of just about any alignment, parametric EQ of nearly any frequency, gain and Q; notch, high shelf; low shelf or phase shift. The MS-8 assigns the filter type and values (frequency, Q and gain) based on the measurements it makes and the algorithm (predefined process or set of instructions for making decisions written as code) that determines how the decision will be made. So, for the purposes of this discussion, MS-8 has 8 opportunities per channel to implement something that does part of the job of fixing the channel's response. The details of how it makes the decisions are proprietary, patented and too difficult for me to try to explain.

I'm sure someone will flame me for oversimplifying this--OK, all you DSP programmers...flame away!
______________________________________________________________

quality_sound : 
_So is the process manual or automatic? I know I've heard that it's got manual controls but are those in addition to the automatic controls or on top of? What I mean is, do the manual controls adjust the settings done by automatic process or is it a separate set of filters?
_
Andy Wehmeyer :
Some of it is manual and some is automatic. The user enters the crossover frequencies and assigns the channels. Then the user helps MS-8 make its measurements by placing the microphones and pressing "Go". MS-8 adjusts the EQ and, consequently, optimizes the crossovers and slopes for proper acoustic performance. Then, if you want to make adjustments, you get a 31-band EQ. The 31-band EQ is a separate set of filters that you can use to draw whatever curve you want. 

Unlike most 31-band graphic EQs, the response tracks the settings precisely. What many users expect is that if they boost all the sliders by 12dB, that the response should be flat, but boosted by 12dB across the spectrum. This is almost never the case, because making the filter Qs narrow enough to do that makes the response look like a comb. Making the filters wider provides more gain than one would expect when adjacent bands are boosted. Also, adjacent band boosts and cuts are rarely executed by conventional EQs as one would expect. The math used in MS-8's 31-band EQ adjusts adjacent bands automatically so that the curve you draw is the curve you get. This is a big deal, by the way.

For those of you who have an EQ laying around, plug it into your sound card. Make it a loop-back. Generate some pink noise and look at the response as you make adjustments. You may not like what you see and it's one of the reasons that tuning with a conventional 31-band EQ and using a 31-band RTA rarely results in great sound.

The whole point of MS-8 and the point at which it differs most from every other processor that's come to market so far is that it's intended to provide a bunch of tools you can use easily to be successful in making your car sound great. It's not intended to be the tool corral at Home Depot, where almost anything is available, but it's up to you to learn how to use it. If we just took the on-chip library from the TI DSP we're using and added a GUI, this product would have been finished three years ago, but it would have been just like every other DSP EQ/Crossover. There would have been a bunch of people who can pronounce "equalizer" and who have heard the terms "Butterworth", Linkwitz-Riley" and "All-pass filter" raving about the resolution of the available adjustments, but the success rate in making cars sound great and, consequently, the sales rate for the product would have been just as dismal as every one of its predecessors. 

This industry doesn't need more tool boxes, it needs more carpenters and more folks who are willing to step up to provide real solutions. Giving a guy with no arms a garden hoe and a shovel doesn't get the carrots planted

"Placing the microphone" means putting it on your head and sitting in the driver's seat, turning your head from side to side according to the prompts, and moving to the other seats (if you want optimizations for those seats too). No change there. 

Yup. 10 runtime presets. Once the auto EQ has been run, there's no need to do it again. The correction filters for the car don't change when you add your own spin with the 1/3rd octave EQ. 
_____________________________________________________________

BMWTUBED : 
_Admittedly I haven't read all 2119 posts on this subject, but I have done a fair amount of googling related to the 325i install. I mainly find 3-4 of the same press release information from about two years ago. My question is: is there any documented release of information regarding how each of the 8 channels were powered, passive crossovers used, exact tweeks that Gary made after the MS-8 did it's thing, etc? I would guess the system was powered as follows, but would love confirmation if anyone knows:
left tweet / mid - 1st chnl (using passive x-over?)
center tweet / mid - 2nd chnl (using passive x-over?)
right tweet / mid - 3rd chnl (using passive x-over?)
left mid bass - 4th chnl
right mid bass - 5th chnl
rear left tweet / mid - 6th chnl (using passive x-over?)
rear right tweet / mid 7th chnl (using passive x-over?)
subs - 8th chnl 
_
Andy Wehmeyer :
Stock speakers in a BMW winning a major competition 
Almost sounds too good to be true
Almost correct. Sides and rear were driven by the same two output channels. JBL PX 300.4 amps on all the stock speakers and a BPX 2200.1 on the subs. Tweeter was added to the sides, rears and center with passive crossovers. 

No additional tweaks after the autotune. The car won using the "compromise" optimization for the two front seats

Custom built passive crossovers I assume?
Just a capacitor on the tweeters. I think a 4.7uF.


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## Tendean17

lenkiatleong : 
_Does anyone understand what Andy meant by "The car won using the "compromise" optimization for the two front seats. ". This comment sets me back one step. I was expecting MS8 to sound as good in term of image and soundstage) as what Mark Levinson has done for Lexus cars where every one in the car get good image and soundstage. Am i wrong to assume this?_

Andy Wehmeyer :
The Auto EQ measures the distance (acoustic) to all the speakers connected to each of its outputs. Then it EQs the combinations of channels that are assigned to each spatial location (right front, left front, center, left side, right side, left rear, right rear and sub). If you choose the driver's seat listening position, time alignment is optimized for that seat, just as it is with other systems. If you choose the passenger's seat, it's optimized for the passenger's seat. If you choose "front seats", then the left and right time alignment is defeated, but individual driver time alignment remains (midbass to tweeter, for example). 

Obviously, with no center channel, this works like any other time alignment scheme. Only one seat can be optimum. A center image in a stereo system depends on mono information arriving at precisely the same time, at the same level and with the same frequency response from both speakers. If you have a center channel and Logic 7, a great center image no longer depends on this because mono information is steered to the center speaker. If the center speaker has the same bandwidth and the same frequency response as the front right and left, it'll work fine. The driver's seat and the passenger's seat will sound the same. 

What if your center speaker won't play below 300 Hz and you have to rely on a phantom center image for sounds below 300 Hz? MS-8 steers information below the center channel high pass filter to the right and left and eventually the subwoofer so nothing is missing. However, the left and right midbass wont be time aligned for either seat. 

Is it a big deal? Not really, unless you plan to use only a pair of tweeters as a center channel. 

Car audio enthusiasts typically prefer a strong and stable center image and OE consumers are less critical regarding imaging. There's an ongoing fight about where the center image should appear. I believe--after 25 years of building cars for customers--that it should appear in the center of the dashboard (or the hood, if possible) no matter which seat you sit in. Some of the folks who build OE systems believe the center image should be directly in front of each listener. MS-8 is tuned so that the center is in the center. If you like it the other way, it's simple to adjust--just turn the center channel down a bit in the menu. 

MS-8 is not going to do everything perfectly--it wont peel apples or make gold out of a rock from your front yard--it isn't designed to be all things to all people. If you believe that you have to have a high-end D/A convertor or you have some other highly technical REQUIREMENT, you may find that another product meets your needs. MS-8 isn't some gold-plated, gold-PCB, million-dollar connector laden class-A multi-channel amplifier with all kinds of super esoteric crap designed to appeal only to enthusiasts. Those kinds of products make regular folks like me afraid to try audio as a hobby. I don't believe that in order to enjoy listening to a great sounding system, one has to be endowed by God with some heightened sensory perception and to be so enthusiastic about the gear that one would read (and take seriously) all the flowery prose intended to make religion out of science. 

MS-8 is designed to make a great sounding system available to anyone who wants it at the most reasonable cost possible. There's plenty of high-end thinking packed into the little box and none of the components are compromised in the interest of shaving cost. We also haven't included any esoteric junk that inflates the cost for limited return. This is an exercise in reaching the point of diminishing return in parts cost and providing performance and ease of use that are without equal. If you're willing to stretch a bit in your opinion of what is and isn't required for great performance, MS-8 will be fun and eye-opening for you. 

I'm expecting another iteration in the mail on Monday to begin final testing of input use cases--testing of UN-EQ, Logic7, all of the audio controls, etc, while the engineers finish coding the auto EQ for the TI610 DSP. Once that's done, we'll send the design to our validation team for final testing against the product spec-to be sure there are no noises or misbehavior. 

This thing has taken so long to develop that there's no way we're going to skimp on validation. I can only imagine the backlash if we release something that hasn't been fully tested and we can't provide an answer to all questions regarding setup or use in various systems. 

If the DIY spirit is about doing things yourself with parts you find at radio shack at great cost in money and time and you're a hardcore DIYer, MS-8 isn't for you. This thing is designed to be a tool that nearly anyone can use to be successful in building and setting up a great sounding system or improving an existing but not-so-great-sounding one without having to spend thousands of dollars on esoteric drivers, fiberglass kick panels, additional amplifiers (unless you require a car that plays much louder than a premium factory system), ridiculous interconnects and speaker cables, etc, etc, etc. If the DIY spirit is about finding tools and gear that allow you not to be dependent on a retail installer who claims that all of that is necessary to have a great sounding car, then MS-8 is what you need and will be worth the wait.

Sorry it's taking so long. I hope it'll be worth the wait for all of you. It will be for me. I have 50 people at work asking me every day when they'll be able to get one
______________________________________________________________

Andy Wehmeyer :
So...I'm back in LA for a week of meetings and spent some time in the MS-8 lab today. Next week, we should have the first fully-integrated software build and we'll start the rest of the debugging. The various modules have been debugged separately. 

It sounds great and it works great too. 

Here are a few cool features that might go unnoticed:

1. The subwoofer level control is a shelf filter that's applied to all the channels through the crossover instead of the usual gain control that most everyone else uses as a sub level control. The benefit is that once you get the bass sounding like it comes from the front (oh yeah, that's automatic) you can adjust the subwoofer level all you want and it never sounds boomy and never gives away its location. We were listening in the lab and we moved the subwoofer all over the place, ran the auto EQ each time and no matter the location, it always disappeared into the sound of the rest of the speakers. No amount of sub level adjustment with the shelf filter made the location any more obvious. 

2. The 31-band EQ precisely tracks the curve you draw with the "sliders". With most graphic EQs, adjusting two adjacent bands in the same direction (say +6dB) will give you quite a bit more boost at a frequency in between the two sliders. If the filter Qs are narrow, you'll get two peaks at the proper amplitude, but with a hole in the middle. The EQ in MS-8 adjusts all the adjacent bands automatically to precisely match the curve you draw. This is a big deal and no other car audio EQ that I know of includes this "math". If you want to see what happens with a regular EQ, hook one up to your analyzer. If you use a PC and sound card, just connect it in a loop, play some pink noise and adjust a bunch of the sliders--you'll be shocked. If you find one that does what MS-8s EQ does, I'll be shocked. 

3. The UN-EQ not only flattens the response, but it also removes any channel delay present in the OE system. 

I've explained these features in previous posts, but they've basically been little additions to my wish list and today I saw them all working--and working perfectly. Ahhh...like Christmas for a little kid

If you want to use a laptop-based analyzer to check MS-8's work and to help tune the graphic EQ according to your taste, believe me, it's much simpler to have the laptop running only the analyzer. That way, you don't have to switch back and forth between windows. 

The biggest difference and the one that will make MS-8 a better tool for making cars sound great is that all of that work that you're used to doing with crossovers, a bunch of EQ channels and delay settings are done automatically. The setup process is a serial process because everything is optimized once you finish the measurements. Setting crossovers is a matter of driver safety and potential output level, but you just make suggestions with the settings you input. The crossover points you choose are the ones that get implemented, but the response shapes are dictated by the combination of the EQ, which is applied before those filters, and based on an average of 6 measurements and the filter settings you choose. 

All of the trial and error that IS current car tuning with conventional tools is eliminated and replaced by a process that knows the measurements and, through an algorithm (a list of instructions that aid the machine in making decisions), determines which solution set is most appropriate for fixing the acoustic problems. It WILL do a better job than any manual process at arriving the best possible optimization of the system, according to accepted science, the preset target frequency response and the requirement that the car has an image where the center is in the center of the dash, the stage is in front of the listener and the bass sounds like it comes from the front. Of course, that science doesn't take your preference into account and that's why we provide the tools that you'll need and want to make changes according to your preference. 

It cannot fix a really ****ty system, but it can do a better job of making even a ****ty system sound better than another process. The use cases that it will support are based on reasonable and realistic system design. The minimum supported system is a simple stereo system--2-channels. A stereo system can be up to quad-amped, but the subwoofer output is a mono signal (2 output channels are available). I fyou insist on stereo bass, then you can tri-amp the stereo system. If you use rear speakers, subtract 2 channels from the channels available to do the rest. If you use a center channel, subtract one more. With MS-8, there's little benefit in separate channels for tweeters. The ease of crossover adjustability in tuning is moot--since you're not tuning and time alignment is unnecessary up there. MS-8 sets the levels and the response shapes via the EQ. We provide the ability to use separate channels for those who want that, but the addition of a center channel or rear or side speakers is a FAR better upgrade.

When we started designing this thing, I told the engineers that the auto-tune was fine, but that i wanted a back door to the target response and all of the filters because I believed my process, performed manually, would provide better results. Now, I know that was BS. It DOES provide my results because it's my process built in a little box that thinks much faster than I can and can sort through all the possible optimizations in a few seconds. It isn't a compromise


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## Tendean17

Andy Wehmeyer :
OK. So here's the update.

We've confirmed that the automatic acoustic EQ works with all supported use cases--and it sounds great. We've tweaked the target to provide a little more bass than I like, but the user menu includes a control to reduce and increase it.

We've added a "bypass input setup" to the setup menu, so if you have an aftermarket radio, you can bypass the Un-EQ part of the algorithm if you have a full-range output from the radio.

We've also discovered, in all of this testing, that CD transports and pickups are sometimes good and sometimes not so good. The algorithm that detects left and right and picks the impulse peaks to determine polarity and factory time alignment works PERFECTLY, so long as the CD player clocks at 44.1k. That might seem like a "given", but in reality, it isn't. We've discovered inexpensive and expensive aftermarket decks that don't clock at that rate and even some high-end OE systems that are off by enough to wreak havoc with signal correlation at high frequencies. 

We're hot on the trail of a fix for that and should have some working code that eliminates that problem in short order. 

What we're most interested in is a simple installation procedure that doesn't require any user troubleshooting, and in the interest of that objective, we've eliminated the audio-sensing turn-on, and have opted for a REM IN terminal that should be connected to the head unit's REM OUT connection. If that doesn't exist, then REM IN must be connected to the car's ACC terminal. MS-8's REM out terminal should turn on ALL the other devices in the car except the radio. For OE systems that don't include a REM wire for amp turn-on (some CAN-BUS and MOST systems), connecting MS-8 to ACC will suffice. We'll include a turn-off delay that's programmable to help eliminate any audible pops.

At this point, it's full-steam ahead.
______________________________________________________________

matt1212 : 
_Andy, Just curious why is it that when using an aftermarket head unit (Pioneer F90BT) with a front rear and subwoofer output its better to use just the front input signal? I would have thought that it would have been easier for the logic 7 to know all three?
Also, I'd assume this means that the signal from the head unit should be completely unprocessed, as in the full 20hz-20khz signal? (No crossovers, bass boosters, etc...) 
_
Andy Wehmeyer :
Logic 7 generates center, side and rear from the 2-channel signal. Many of the other 5.1 algorithms are designed for rooms where the TV is the vocal point, dialogue is most often reproduced and where the center speaker is similar in size to the left and right, and finally where the seating positions are more similar to the standard equalateral triangle. It doesn't need to know the center and side information from discreet outputs. If you'll watch or listen to DVDs, just select the 2-channel downmix in the disc setup or the setup menu for your DVD player. In that downmix, the canter and surround information have been "encoded" into stereo and L7 will play back in full surround. Generating the sub signal for the car should always be done by MS-8. LFE channels for rooms aren't optimal for cars. Plus, just hooking up front channels is simpler.

As far as the additional processing in the head unit goes, it's pretty important to defeat the surround processing, if possible. MS-8 can't downmix perfectly if it's fed center and sides. If you run setup with bass and treble boosted, MS-8 will flatten the signal

Hey there, Hairy Night Creature,
Yes, that's right. If you don't install the display, the unit remembers all the settings when it's unplugged. It's like having stored only one favorite. In that case and if you've done a bunch of bass boosing in any of the EQs or level controls, I suggest setting the MS-8 volume below 0dB to accommodate that boost by a few dB and using the factory control. Obviously, the factory volume control's loudness and dynamic EQ won't be eliminated, but those settings are usually chosen to "correct" for some ambient characteristics (road noise, etc) or a simple equal loudness contour and they often improve the performance anyway

There's a lot going on behind the scenes that isn't apparent. the center frequencies on the 31-band EQ aren't adjustable, but it's really a drawing tool. Ms-8 will implement any curve you draw. Since the channels are already matched by the autotune, this is much easier and you don't need an RTA. As far as clipping and distortion are concerned, this unit doesn't operate any differently than any other unit. If you clip the head unit, you'll hear clipping. If you clip the DSP, you'll hear clipping. How would you suggest that we monitor a music signal from the head unit to determine if it's clipping? The unit does that during setup, but it can only do that because the setup CD includes a known MLS signal that MS-8 correlates to determine the impulse response. It has no idea what the music content should be.

Of course there's short circuit protection on the speaker outputs.

This thing will make your car sound great and that's what it's supposed to do. It was never intended to be an iPhone or a studio mixing console. 

Think of this as a great backyard BBQ without the white tablecloth and water "with gas" that you'd find at Tavern on the Green


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## Tendean17

Mic10is : 
_Andy what are the available XO points and slopes? Are the Xo points fully selectable or are they preset at like 1/3octaves? Which slopes are available and what type are they (linkwitz, butterworth etc...)
Do you think in a future upgrade it may be possible to allow all functions to be tweakable after Autotune?
also, what would you say is an ideal speaker size for center and rears in a Logic 7 set up? _

AdamS :
Crossover Points are in specified in exact Hz. There are min and max frequency values in some places to prevent errors.
Slopes are 6,12,18, and 24 dB/octave
We use Linkwitz-Riley wherever applicable, otherwise Butterworth
______________________________________________________________

Mic10is : 
_Andy what are the available XO points and slopes? Are the Xo points fully selectable or are they preset at like 1/3octaves? Which slopes are available and what type are they (linkwitz, butterworth etc...)
Do you think in a future upgrade it may be possible to allow all functions to be tweakable after Autotune?
also, what would you say is an ideal speaker size for center and rears in a Logic 7 set up? 

_Andy Wehmeyer :
Adam has already answered the question about crossovers.

I think once you try thie product, you'll find that all of that other stuff dosen't need to be tweaked after autotune. One of the reasons that we're all after all of this control of every parameter all the time is because stuff is never quite right. Trying a thousand iterations of crossovers and EQ takes us a long time, but it doesn't take MS-8 very long to try thousands of solutions. The slopes and frequencies get adjusted when each channel receives it's share of the EQ. Furthermore, MS-8 builds the system as you enter the info. Tuning with crossovers is overrated and I find that there are basic settings that work for almost all systems, so long as they're EQed properly. I can't tell you how many championship-winning IASCA cars I've helped out with where the single biggest problem was crossover selection based on a bunch of wishful thinking. Front stages crossed at 40Hz while the sub was crossed at 60 or 70, midbass that plays from 40-60Hz, etc. The best way is to use steep slopes, minimize interaction and cross speakers ABOVE their resonance. So long as you follow those rules, you'll be happy with the results. 

MS-8 may make this so easy that some of the mythology that currently makes tuning an "art" may be dispelled. I'd love that and so many more cars will sound great as a result. 

At the begining of this program, I told the engineers that I wanted a back door so I could tune stuff myself. I no longer want that back door, I just want an MS-8 of my own so I can put away the RTA and the mics and have fun listening.

Fortunately, I get serial #1. Adam already has one
______________________________________________________________

Andy Wehmeyer :
Well...that's a good question. That one uses a DIRAC autotune, which is a fairly long FIR filter for each output channel. In my opinion, it's kinda like taking a Sikorsky SkyCrane to the grocery store. I've never heard it, but considering the amount of processing in there, there's no excuse for it not to sound great already. What improvements are you hoping for?

If you'll help me out a little bit and tell me how much power the marketing materials say the 9-channel amplifier provides and tell me the year of your car, I'll look up the connections in the chassis wiring book and see what can be done. 

There is one potential problem with using the output of the factory amplifier--the FIR filter equalizes phase and frequency response. Logic7 in MS-8 relies on flat phase to steer front and rear. Depending on what the FIR filters actually do for each channel, it could cause some strange steering. 

Send me the info (power and year of the car) and let's see if the DIRAC amp is MOST or how the head unit hooks up to it. I think some of my DSP buddies at work have some documentation too. I'll check with them.

Here's my take on the car tuning thing:

An algorithm can only be successful in meeting its objective if the person describing or implementing the process knows what he's doing and can communicate the process properly to the person writing the algorithm. I know how to tune cars and Ulrich and Adam know audio and math. That's why MS-8 works. 

The performance of these kinds of things has far less to do with the components (DSPs, D/As, speakers, filter types and amplifiers) than it does with the target curve and the method by which the machine arrives at the target. I'm sure that MS-8's autotune won't make everyone happy, but as Technic says, having some additional tuning tools will help to satisfy the tweakers
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Se7en : 
_Andy, I have a question regarding the time allignment functionality of the MS8.
I have been a Tact Audio user for about 11 years now and this system also features automatic room equalization and time alignment correction. One of the realities/negatives about the Tact correction system is that it is not "self aware" of it's own processing time (which increases/decreases based on frequency and XO slope selection) and does "not" make appropriate adjustments to it's TA corrections. This means that often out of the box adjustments can be mis-alligned.
A number of Tact users have published useful charts to help users perform manual TA adjustments to the auto allignment based on XO frequency and slope between the subs and mains (in a home system).
I was wondering how the MS8 deals with this especially given the number of channels supported. Thanks! 
_
Andy Wehmeyer :
Great question and a big problem if you sit far from the subs and speakers. In a car, we sit very close. Delay based on distance in a car is a very few degrees of phase at most sub/midbass crossover points (unless the box is in the back of a Ford Excursion and you're 4.5 feet tall). Using a really steep slope (4th order is sufficient) will minimize the interaction of the sub and midbass enough to make a good transition in the car possible. Since we're not using FIR filters, the computation time is relatively short for EQ and doesn't vary from one channel to the next regardless of how complex the filter is. We have compensated for the difference in processing time for the sub and the other channels. 

The real difficulty in the processor is in the bass management section, where steered low frequencies are added to other channels below the crossover frequency of the channel to which that bass was originally steered. Thanks to Ulrich and Adam, we have an ingenious arrangement of additional variable all-pass filters that match the phase of the steered bass to the unsteered bass.

While that's not the answer, precisely, to your question, it is an cool part of the MS-8

Oh, one additional thing that should be mentioned. In any peak-picking algorithm designed to acoustically locate speakers or align signals, the amount of high-frequency in the content affects the algorithm's ability to locate the speaker, especially if a stndard impulse response measurement will be used. In MS-8, this applies to D-EQ and Auto-EQ. Once again, Adam and Ulrich have figured out a cure for that too.

The one problematic configuration is a 2-way speaker using a passive crossover where the tweeter is much closer to the listener than the mid. My tip for that scenario is to cover the tweeters during the first of the 4 sets of sweeps for each seating position. That will cause the MS-8 to align based on the output of the midrange, which is important because we use ITDs to localize sounds below 1kHz, and then the EQ will take care of the ILD at high frequencies. Works like a charm


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## Tendean17

Andy Wehmeyer :
We haven't done any listening tests in the same car, same system with two differnt head units. From a technical perspective, I don't think it matters much, so long as the dynamic EQ from the OE system (if such a thing exists) in the car provides acceptable improvements

MS-8 matches all the channels and tries to maintain plenty of room to avoid digital clipping. If you use MS-8's amp for the center, it'll adjust right and left to match it. same for rears. I suggest using similar power for center right and left. If you use the MS-8's amps for the rear, sent the gains on your amps down a bit, run setup and then adjust the amp gains up by precisely the same amount until you get a balance between front and rear that you like. Same goes for the sub. If the sub "level control" in MS-8 doesn't provide enough bass for you, adjust the amp gain up after you run setup.

The spatial average helps to smooth the high frequency measurement, which is always inaccurate with a single mic placement. If you mod the mics for an inner-ear implementation, you'd need a new mic correction filter and honestly, I don't think it'll matter much. The difference would probably be a little more high-frequency content allowed from the rear speakers

Lycan is right. 

In fact, I'd go so far as to say that a mono (L+R) center does more to screw up a good image than to enhance it, unless there's some additional trickery involved in the processing, like crosstalk cancellation, but that isn't available in car audio products.

For 2-channel listening, a matrix processor (PLII or L7) is the ticket, although getting used to listening to music the way it was recorded takes a little while. We're so used to listening to different pathlengths that many of us like the sense of space that those phase anomalies provide. 

I did a demo for a well know record producer several months ago of a car with a strong phantom center image and his response was "it sounds mono". the demo was of a track he mixed. We then went upstaris and I showed him exactly how much distinct left and right were actually in the track and he scratched his head.


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## Tendean17

Andy Wehmeyer :



Andy Wehmeyer said:


> OK, now that my butt has recovered from 15 hours in the same chair yesterday, here goes.
> 
> Every few milliseconds, Logic 7 computes a steering angle by determining a couple of things about the stereo signal. Left, right and center steering is determined by level differences between left and right signals. Mono information--the information that's common to left and right--is steered to the center. Don't confuse mono as L+R for what's actually going on here. Although this isn't how it's done, you could think of the mono info as (L+R)-lL-Rl. It's all of the sound minus the sound that appears only in the left or the right. That mono information is also attenuated in the left and the right. The amount of that information that appears in left and right is an important part of making this thing sound great in cars. If the information is completely removed from left and right, then I don't think it works very well in cars. The images are spot on, but they're really small and don't sound believable, to me. If the mono information isn't attenuated at all, then the stage is narrowed a bit and the images are big and kind of nebulous. Left of center and right of center aren't very accurate. Attenuating the mono signal in left and right by 6dB works great and that's what MS-8's L7 does.
> 
> The front-to-rear steering angle is computed by determining the phase relationship between left and right. -180 degrees steers to the rear. -90 degrees steers about halfway between front and rear. The level differences between left and right determine rear left and right steering.
> 
> Finally, when information is steered front, one of the rear and side channels is polarity-swapped. This helps to anchor front steered sounds in the front, and that's why sides and rears shouldn't make a bunch of midbass. That out-of-phase condition in the back works for imaging, but not for midbass. Fortunately, we all want the midbass to sound like it comes from the front, so it's just easier to make sure that it does.
> 
> Side and rear are also delayed by several milliseconds, but rear is delayed more.
> 
> Very low frequencies are not steered. They're simple stereo.
> 
> Here's a set of drawings that sort of illustrates this. The first one illustrates what you can expect from a L+R center.
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> And here's a simplification of what happens with L7:
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> So, when you implement this in a car, here are some pointers:
> 
> 1. Sides and rears don't have to make bass. I use a 3" and a tweeter in the back and a 6" component system in the sides, but they're crossed over at 100Hz, 4th order. The 6" speakers in the sides are overkill, but that's what fit in the doors.
> 
> 2. It's helpful if the side and rear tweeters are at about ear level. Don't mount them in the bottom of the doors.
> 
> 3. If you won't put 4 speakers in the back and you'll use only 2 instead, MS-8 will process them as sides. That's no problem and the difference between 5.1 and 7.1 is really hard to hear. It's nice to have rears and sides if you'll have rear seat passengers. Logic 7 in OE systems mixes some front-steered information into the sides, so the rear seat passengers have their own stage at the back of the front seats. Making those adjustments is car and speaker-location dependent and it's seriously difficult to do without screwing everything else up. MS-8 will provide a single stage, located at or in front of the dashboard for all seating positions. I prefer that and it happens automatically and easily when the front seats are right.
> 
> 4. Front steering works perfectly for all frequencies that the center channel will play and pathlengths don't matter much. For midbass frequencies that the left and right will play but the center channel won't, pathlengths are critical. A phantom center has to be generated for those sounds. If your center channel is a 3" and you have big-ass 8" speakers for right and left mounted in your doors, there's gonna be trouble.
> 
> 5. The subwoofer level control in MS-8 isn't a level control for the subwoofer output channels. It's a shelving filter that boosts bass in ALL channels below 60Hz, but never above 160 Hz. When you boost or cut, the slope of the filter is adjusted. This helps to maintain the illusion of bass up front by sending the appropriate amount of midbass to the front speakers and bass to the subwoofers. It also maintains the crossover point. Here are a couple of graphs that illustrate this and why it's better.
> 
> The first one is a conventional control. It's pretty obvious why this moves the image of the bass to the back and sounds boomy. There's too much interaction between sub and midbass. This is why people claim that "underlapping" the bass is important and why so many people try to get big-assed midbass drivers in the front of the car and cross the sub at 50Hz. With MS-8, that's totally unnecessary, and the evidence of that is in the second graph.
> 
> I use a pair of 6" speakers driven by about 40 watts in the doors, another one in the center channel and a 500 watt amp on a pair of cheesy 10" woofers in an IB in the rear deck. The bass is seriously anchored to the front and the midbass is great. No hassles, no constant tweaking and I can boost bass by as much as 10dB on top of the target curve (which is a total of about 20dB) without the image shifting to the rear. I think my crossover point is about 80Hz, 4th order.
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> BTW, this feature is also included in the MS-Amps using a wireless rotary control that can be paired to any number of bass and full range amps in the system.
> 
> So, for front right left and center, you'd be better off with three 5" speakers (R,L, and C) than with 8s in the doors and a 3 in the center. If all you can get in the center is a 3", then try to move the midbass to the kick panels. If you can't do either, the car will still sound great, but the image for center-steered midbass sounds will be larger than it should be and will be biased a little bit to the side on which you sit. Not such a big deal.


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## Tendean17

BMWTUBED : 
_Isn't this more or less what the MS-8 Biggs BMW had? Except the 8s are under the front seats and the center is a 4" (I think)
_
Andy Wehmeyer :
Yup, and it works fine, with the same caveat about midbass placement. was good enough to win IASCA at SBN, but the under-seat placement is a little better than in the doors. We crossed the MB and the 4s at 200Hz, 4th order
______________________________________________________________

Andy Wehmeyer :
The 2-channel downmix available on most DVDs is designed to encode the discreet channels into the 2-channel mix in a way that matrix processors can decode. See the diagram above for a clue about how those signals are mixed in. If you were in your living room at home, then there would be no reason to do any of this. The encoded stuff is designed for listening in rooms an designed mostly for movies. The principal objective (as it seems to me) is to anchor dialogue to the screen and provide 3-D effects for movies--flyovers, frog noises all around, dinosaur steps that shake the house, etc. From my perspective, LFE and bass management are fancy terms for "crossover and summing circuit". While they may be complicated to explain and they sound cool, bass is easy and it's even easier in cars. 

Some music DVDs are mixed in multichannel so that they place te listener in the audience and some are mixed so that they place the listener on the stage. You can probably guess what my perspective on that is. In any case, discreet algorithms are often panned by music lovers as "non-musical" sounding and I tend to agree, unless the system includes a huge center channel and subs placed all over the room and are tuned differently for music than for movies. Furthermore, I've never in all my life heard a multichannel movie demo that i cared about. I've never heard an explosion or a dinosaur and have no idea what they're supposed to sound like. 

MS-8 is designed to make cars sound great, but not necessarily to preserve all the whiz-bang technology that marketing materials for multichannel processors and processes tout. The primary benefit of Logic 7 in cars, considering the overwhelming use case of 2-channel material over discreet multichannel recordings is in center channel processing to overcome the installation headaches of kick panel mounting necessitated by off-center seating. For cars that have a center channel location this is a big deal for a pair of listeners in the front seats. Even for single seat listening, I prefer a dedicated center channel. A secondary and more subtle benefit is the front rear steering and the sense of ambience it provides. This depends on the recording, but I've never wanted to turn L7 off, no matter what I'm listening to. Of course, none of the multichannel stuff means much if there's no room correction, and that's the primary sonic benefit of MS-8. Finally, the fact that this thing can be hooked up to nearly any system is important too. 

Logic 7 is not intended to synthesize a room independent of what's contained in the recording. Room synthesis is a separate project and that's why there's a mac Mini in my car--hint, hint...

Compared to what else is out there for making cars sound great easily, MS-8 has no peer, unless you're a seriously accomplished tuner with some tools that aren't available in over-the-counter car audio prodicts
______________________________________________________________

Technic : 
_So other than the 31 band EQ for manual adjustment, the MS-8 auto-EQ curve should be fundamentally the same used as the OEM? 
_
Andy Wehmeyer :
No. The BMW doesn't autotune. The curve is different. The bass contol is completely different. The tone controls are different. MS-8 allows you to save favorites and optimize for different seating positions. The MS-8 includes preamp outputs, a display and a remote control. The MS-8 provides a center output that supports a tweeter. The MS-8 will do 7.1 and the 3-series BMW is a 5.1 system. The MS-8 is fully configurable and will support 48 different speaker system configurations. 

I'm not sure what kind of answer you're hoping for. If you want me to tell you that MS-8 will provide better sound than the L7 OE system, I can't that depends on your requirements. If you want me to tell you whether it will sound better than the DIRAC system, I can't do that either. I've never heard one
______________________________________________________________

Technic : 
_The question was more towards what differences are between the Logic7 processing and implementation in the MS-8 and the BMW OEM version, not what the MS-8 can do other than that.
And so far there are at least 4 distinct differences. 
Thanks. 
_
Andy Wehmeyer :
These are the main differences. 
1. Bass Management is not done inside of MS8's L7. L7 doesn't generate a subwoofer channel. It is done with the MS8 Allpass / Bass Management system alluded to earlier by Andy.
2. MS8 handles 45+ configurations. Whether the system is 2.x, 3.x, 4.x, 5.x, 6.x, 7.x, etc, Logic 7 will be optimized. 
The rest is pretty subtle
______________________________________________________________

Andy Wehmeyer :
The EQ, time alignment and user adjustable features work whether L7 is on or off. Yo may find that those features provide such a benefit that the additional spatial effects provided with your discreet multichannel recordings pale by comparison. I can assure you that if you can select a 2-channel downmix, the playback will be better than a discreet solution that doesn't include great EQ and time alignment


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## Tendean17

Andy Wehmeyer :
The guitar and the vocal don't travel through the PCB nor the solder. A simple alternating current passes through them and yes, it'll make it through to the other side just fine. The point is that it's necessary to change the signal to make up for the deficiencies in the acoustic system. Think of it as believability rather than accuracy. 

How about this. Let's say your wife or girlfriend sends you to the store to get 10 cans of Green Giant creamed corn. You're walking home from the store with the corn and as you round the corner at the stoplight, someone jumps out from behind a bush, hits you over the head and tries to take 5 of those cans. You fight him off, but 5 of the cans are dented and the labels are scratched up. Knowing that your significant other won't tolerate anything but the most pristine of cans, you walk the rest of the way home lamenting the damage. Just as you turn to enter your driveway, there's a guy who can, with the wave of a magic wand, restore the cans to like new condition. In order to get him to do it, you'll have to renounce your belief that to repair the cans and the labels is somehow an anathema and admit, for all to hear, that a repaired can is, in fact, equal to an unaltered can. You reluctantly agree, fall on your knees and recite, "A can is a can and will always be a can so long as it's a can." The can wizard smiles and with a wave of his wand, the cans are as good as new. 

You enter the house, and your wife (or girlfriend) asks, "Hey, what was all that commotion I heard outside?"

You reply, "Nothing, honey. I was concerned that the cans of corn might have been degraded during my walk home. Here, check them out."

To which she replies, "Wow, these are the most beautiful cans of Green Giant creamed corn I've ever seen. I don't remember the picture of the corn being quite so vivid and the logo really stands out. Hey, check that out. You can almost make out the shape and size of the Giant's giant wand. Oh my God. You're so handsome. Dinner can wait." She leads you upstairs to the bedroom and makes love to you like you were both 19 again. 

Hmmm...I'll take some...EQ, that is, and a bunch of other signal processing too, especially if it makes listening more enjoyable
______________________________________________________________

Andy Wehmeyer :
I'm not getting into a super lengthy discussion of the differences between using TA and equalizing pathlengths. That's been discussed and hammered on ad infinitum on this form and on others. From my experience, the difference isn't worth the hassle and the kick panel locations in many cars cause as much difficulty (frequency response and the car's drivability) as they eliminate (near side bias). 

If you want to solve the problem once and for all and don't want to make fabrication your life's work, use the existing center channel location (if your car has one), buy an MS-8 and leave the right and left speakers in the doors. If you don't have an existing center channel location, then you'll have to choose. MS-8 makes the choice a little easier by providing good auto EQ and TA and it takes 5 minutes to tune. 

I've seen some 5-minute kick panel jobs and none of them sounded very good--they were precisely aimed with a laser, though
______________________________________________________________

BMWTUBED : 
_Andy,
I'm planning something very similar to the 3 series you and Biggs did.
What are your thoughts on using a good mid/sub in the underseat locations and foregoing the sub in the rear? I was thinking of the Morel ADMW9 running
30hz - 200hz. Any real down side to this other than the low end limitation? 
_
Andy Wehmeyer :
Keep the subs that are down there. I use a pair of the same 10" models in an IB in my rear deck and they rock. A couple hundred watts each and you should be fine (so long as you're not a basshead). If you decide that you need more bass, consider adding a sub in the back. Just changing out the speakers under the seats isn't going to be a night and day difference
______________________________________________________________

MattyKHZ : 
_OEM and SQ is what I am after which I believe is what the Audison Bit One was providing once all the bugs had been ironed out.

Reading the whole of this thread it seems that Logic 7 and centre channel usage is what the MS-8 is all about. Unless I am wrong.

I am wanting to get the best out of my Denon amps and MB Quart speakers in a 3 way active set up from my OEM HU in R56 Mini Cooper S. As the MS-8 will probably not be over here this summer with US probably getting the first allocation I would have to look elsewhere and Audison seem to offer everything I need and be available.

_Andy Wehmeyer :
I'd say that L7 and its center channel processing are a big bonis, but the fundamental advantage of MS-8 is the signal summing and conditioning and the auto EQ. The BitOne is a great piece of gear too. If you're a good tuner, you'll be able to make the car sound good. If you're not, the MS-8 is the tool for you.

Basic signal summing and un-EQ for the factory signal is one VERY small part of the chain. There's nothing very important about getting a flat signal from the head unit unless you're also running a process that requires a flat, in-phase signal. Furthermore, simple analog summing is an insuffieicnt solution. The output signals from many factory systems include delay, which will cause comb filtering in the summed signal. Is that a big deal? Depends on how low the first part of the "comb" is. If it's in the midrange, then it may be a big deal. MS-8 fixes that by eliminating the relative delay.

Matt,
Obviously, I'd like you to have an MS-8 and you'll get an email this week from our office in Amsterdam, but I also understand that delivery timing is a big part of your decision. Over the course of the last 3 or 4 years I've helped several people here and on the carsound forum choose the best alternative because they couldn't wait any longer. If you can't wait any longer, I suggest choosing an alternative based on whether you have an RTA (or have access to one) and whether you're good at tuning cars. If you are, the BitOne is the right way to go. If you're not and you can't wait any longer, get the Alpine.


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## Tendean17

2DEEP2 : 
_Andy spoke like a true Product Manager, knows where his product is...
But someone can offer a short sell on product before it even hits the street from the OEM... Hmm.
You know China has some great engineers, they can copy just about anything 
It would not be the first time a Chinese firm committed patent infringement. 
Aren’t those fake Focals from China?
_
Andy Wehmeyer :
Not possible with this product. The DSP in this thing is a custom part built only for Harman. Additionally, some of the other components are seriously long lead items (120 days) and we've gobbled up the entire world's existing inventory. I can't say that there will never be a counterfeit MS-8, but I can say with certainty that a counterfeit unit won't be available first. 
______________________________________________________________

ibanzil : 
_When using imprint there was a way to open up the files audyssey used when calibrating the system. Will there be any way to see what the MS-8 did as far as adjustments to TA, eq, and such?_

Andy Wehmeyer :
Nope, at least not yet. Originally we were thinking about making that part of the code update downloader, but in the interest of getting the project finished, we scrapped that. I thought it would be cool to have a way for users to upload the files to JBL.com so we could provide a view of what had been done through some online tool and so we'd be able to help troubleshoot if necessary and collect data about cars. All of that is a pretty big piece of work and I haven't had time to make a business case for the investment in time that would require. 

Troubleshooting is turning out to be really easy, so far. For the 10 or 12 cars that have MS-8's currently, there have only been a couple of questions like, "Hmmm...the midrange sounds strange", but a 5 minute conversation about the speaker system, a suggestion or two and an another round of acoustic calibration (a 5 minute process) has fixed all of those quickly.

For example, one of our guys has a Dodge Durango witih the OE Alpine system. He had plans for an additional sub, since the factory sub is a little 8" in the back somewhere. He decided that to get started, he'd just put in the MS-8 and do the sub later. He called and said the midrange sounded strange and wasn't super happy with it and I asked if the tweeters in the front were actually tweeters or if they were those standard Dodge 2" high frequency speakers. Who knows? Anyway, the grille was too big for a tweeter and the mids are in the bottom of the doors. He had the crossover set at about 4k, so we moved it down to about 1k to take the mid out of the response before it started to beam and before the first big peak in the response (happens with all cone drivers). 10 minutes later everything was fixed and he's completely happy without adding an additional sub. Must have been 2" drivers...

I guess my point is that if there are so few people who can be successful in making their car sound great using basic audio tools and an RTA, what's the benefit in a print out of some complex series of impulse responses, except to take the techno-babble to a much higher level and expose our I.P to the public? If you want to know what MS-8 did and you have a PC based analyzer, there is a way to connect the analyzer to the input and output of the MS-8 to make a measurement of each of the output channels. In order to understand completely what's going on, especially for any system that includes "fixing" an OE head unit, each part of the process would have to be separated and displayed. When you set up MS-8, it'll be apparent that the process is a series of steps that have to be performed in a specific order. Correction filters for each step aren't saved in memory, but the correction for the end of each separate series is.

If you're technically astute enough to decipher the data, then you're technically astute enough to figure out how to make those measurments with any analyzer that does FFT and IFFT. A careful read of the manual and some careful thinking about the setup process will make that obvious.

Here's a challenge. The first person who figures out how to measure this using an audio analyzer wins a free pair of JBL 660 GTi components--on me. Send the documentation to me, be sure to send the data as screen shots or text files with an explanation of what you think is going on and tell me the equipment you used to make the measurements. Adam and I will look over it and determine whether you're a winner. I'd love to give away a set of these speakers and will give some serious benefit of the doubt in order to give them away.

What I mean is, get close enough and we'll send the speakers. I'm not looking for a loophole to prevent me from sending $2000 dollars worth of speakers--I'm not your health insurance company.

Oh, one more thing. Submissions have to be kept strictly confidential.
______________________________________________________________

Andy Wehmeyer :
Show me what the unit does to the signal for each of the output channels you're using and include what happens to the input signal too and you win a pair of the world's best car speakers. Think of this as a science experiment. You have to show your work or explain it and it has to be presented privately and not as a group effort for all to see on this forum. 
Have a GTG in someone's back yard, figure it out together and appoint someone to be the presenter. 
I'm not giving hints.
Oh, don't bother with Logic7. That'll be too difficult to decipher with the tools you'll have. Plus, I think I've explained it sufficiently here.
______________________________________________________________

kaigoss69 : 
_Andy, for a 3-series BMW (e90) with OE Logic 7, what is the recommended configuration if I am only interested in driver seat optimization? - Would you do exactly what you did with the 2006 325i or based on what you know now, would you make any changes?
_
Andy Wehmeyer :
As far as the speaker system goes, I'd definitely add a tweeter to the center channel. If you need the car to play loudly, you'll want to add amps, but if not, add a sub and use theunder-seat 8" for midbass. It'll work great.


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## Tendean17

michaelsil1 :
_Does the MS-8 save the settings if the power is disconnected?
_
AdamS :
It saves when
1. setup finishes
2. remote in is disabled (ignition off)

If you lose power and get it back, it will go back to 1 or 2, whichever is the newest
______________________________________________________________

rain27 : 
_Is there any way to reset the MS-8 to original factory settings without going through the display menu system??
Pressing the reset button on the unit itself does not reset all settings.
I was wondering if there was any other way????
_
AdamS :
There's one other way, but it hasn't been made public yet.
If you re-download the firmware, it is almost identical to resetting all settings.
The Reset button on the unit is the same as Remote In disable followed by Remote In enable
______________________________________________________________

kaigoss69 :
_The BMW OEM L7 systems are known for the "rear fading issue". I have experienced this myself. The music will sound normal and then suddenly, it would shift certain portions of the song towards the rear speakers. It would sound weird, of course, an not natural as the fading would go back and forth. For me, this happened mostly when listening to FM radio and not so much when using CDs or the iPod. So is this the same issue (phase) and what exactly is causing it? Will it sound similar with the MS-8? How much out of phase information is in today's music and is it dependent on the source?
_
Andy Wehmeyer :
This is why L7 has an "off" position. It's a matrix processor. It does what it does and with most music it sounds great. All kinds of phase shift happens in FM broadcast when reception isn't good. Additionally, FM is about as close to mono as a signal can get and the blend function in many tuners which is designed to make poor reception sound like good reception further monos the signal. 

FWIW, and as DS-21 has stated, all of the matrix surround processors steer according to phase. The difference between L7 and the others is that L7 does a much better job of keeping left and right rear separate. If you like it, use it. If you don't like it, don't use it. If you have a center channel and want to use L7 steering for the front (phase has no effect on front steering), then don't install rears or move the fader to the front. 

Listening to just the rears or the fronts only with L7 is an unintended use and will sound strange, of course. 

One day at CES, some of the EMEA judges got in my car (it was the demo one year) and after listening for nearly 2 hours, one of them jumped out and exclaimed, "I did it. I found something that breaks the code! Listen!" He put on some preposterous recording of a person speaking while pink noise rotated around the car. Of course, with no matrix, the pink noise won't rotate, but the combination of rotating steady state noise and a transient signal like someone speaking break the code. My response? "Dude, get out of here. It took you two hours to figure that out? You're the only one after four days who has cared that the code doesn't work with all songs and all recordings. If I were you, I'd throw that disc away.It won't work in any system. I also breaks stereo, since the noise is specifically encoded to rotate with a matrix."

I have a friend who works at an Italian car audio magazine who refers to those people as the "Car Audio Taliban". Seems fitting.


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## Tendean17

*Prepare your system design first
*









Andy Wehmeyer : 

OK, I'll try to clarify and to overcome my commitment phobia. MS-8 is designed to make a competent system sound great. It can't fix profound errors in system design. Speaker placement is still important, but not as important as it is with basic 2-channel systems.

1. MS-8 can autotune just about anything, but it can't put back what isn't there. There's a lot of boost and cut available, but if it runs out of boost, it runs out of bits and that will cause digital clipping. That sounds like ugly speaker distortion. You can help MS-8 do its job if you hear ugly-sounding distortion by making sure you don't have any huge holes in your response. This is why Adam is suggesting a bacis level matching of your system before the autotune. Some other installation mistakes that may cause MS-8 to run out of boost are:

a. Choosing bandwidths that your speakers are unable to play. Don't try to cross an 8" that's mounted off axis in the door at 3k, for example. 

b. A big suck-out caused by incorrect driver phase. Phase reversal may be a function of distance between a midbass and a mid or a mid and a tweeter. It can also be the result of improper wiring. If you hear distortion and it goes away when you change your crossover point dramatically, this may be the cause. 

c. Choosing too narrow a bandwidth for your midbass and having the gain on the amplifier too low. 

You can determine if the problem is that MS-8 has run out of boost by turning processing off. IF you turn it off and the distortion goes away, check these three things first. If you can determine which speaker makes the distortion, turn the gain on that amp up slightly and recalibrate. If that doesn't fix it, but moving the crossover point does, then try the new crossover point or try reversing the phase of the right and left channels of only that specific amplifier. 

We've only seen this a couple of times and it isn't an MS-8 defect, it's just that the system has too big of a problem for MS-8 to fix on its own. 

2. I don't think I've been noncomitttal on the center channel bandwidth issue. THe center channel should be the same bandwidth as the front right and left. In some cars this is possible and in some it isn't. IF you can only get a small speaker in the center, MS-8 will steer center midbass to right and left. If this is the case, then the location of the front midbass becomes more important. IF you can get your center down to 120Hz, that's great. If not, put in what you can and listen to it. The compromise will only be in matching the listening experience for both seats. the seat for which you choose optimization in the seating position menu will sound great. 

3. The center doesn't play L+R. It plays only what is common to left and right. That's like Left plus right minus the absolute value of left minus right. A mono signal that's the ssame in left and right will steer to the center and will be attenuated by 6dB in the right and left. A left only signal will NOT appear in the center and a right only signal will NOT appear in the center. 

4. Signals that are the same in the left and the right, but are out of phase between left and right will be steered to the rear by logic7. This is designed to help reproduce the ambience contained in many live recordings and the ambience that's faked using reverb or convolution reverb in many studio recordings. It works well, but some recording engineers reverse phase in studio recordings to create some other "effects". MS-8 doesn't know the intent of the engineer (and i don't either), so MS-8 will do what it does. If you listen to a multi-channel recording down mixed to 2 channels, MS-8 will recreate the rear using only the two channel mix. 

5. Rear speakers should be full range, above 100Hz. The high frequencies are helpful in recreating ambience, so they should play to 10kHz. I recommend that the don't play much of anything below 100Hz, because Logic7 reverses the phase of one side of the rear during front-steered sounds to anchor the image in the front. When sounds steer rear, the phase of the sides and rears is corrected to make the steering more appraent. THe reverse phase for front steered images mucks up the impaact a bit, so cross the sides and rears over at 100 Hz or higher with a steep slope. This reversal happens very quickly each time L7 samples the music. I don't remember the interval but it's short--too quick for you to hear. One thing that L7 cannot do is steer a transient signal rear, if a steady state signal is steered front at the same time. I have a recording that makes this easy to hear. Mono pink noise that steers center and a voice that rotates around the car doesn't work. Fortunately, there are very few recordings that are made this way. L7 doesn't work on every recording and recordings that have little stereo or reverse-phase info won't place much info in the back of the car. Live recordings and direct to 2-track will be awesome. 

6. I've never used MS-8 with horns. horns often require lots of EQ to sound right. Thay also require very little power. Be careful with the level of the sweeps, but I don't seeany reason why they wouldn't work. 
______________________________________________________________

Bikinpunk :
Oh, and to you dashmat guys… you can throw that sucker away.
I don’t use one. It was hard for me to get rid of smearing with my bitone tune.
The ms-8 does this perfectly. No ‘walking’ stages, no smearing of voices. Everything is focused and focused well
______________________________________________________________

Bikinpunk :
Yea, right after you go through the system setup, toward the end of that, there's the part where you can test the channels. If you look at video #1 and go to about 5:56, you can see where you're at the "output diagnostics" screen. You can toggle the left/right side on & off. You'll then be able to level match your speakers from this screen and you'll have the protection of the ms8 crossovers. 

You can do this by ear. You can put a mic in the car and do it with an RTA, use an SPL meter, or whatever you want. The other, a bit tougher, method to level match would be to use your drivers' specs, look at the sensivity and if they're all within a couple dB you could just level match at your amps' outputs (ie: set the output voltage to roughly the same). If they're not, then you'll have to do some calculations to give you approximate voltage needed to get xdB output per driver, then set your amps to that. It won't be dead on because the drivers' sensitivity will vary from mfg spec, but it should be close enough.

Another method, if you didn't want to do this at the setup would simply be to move your cd player's inputs (or any source inputs such as ipod) and hook up directly to each amp. Play pink noise, set the gain about where you want it, and then continue. If you do this, though, MAKE SURE that you're careful not to blow a tweeter since you're bypassing the ms-8 crossover. In fact, I'd really urge you to use the ms-8 to level match drivers. I mean, REALLY, encourage you. Not only for driver protection, but because it's just easier. 

Hope that helps.


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## Tendean17

Kkant : 
_When going active on the tweeters, on/off thumps are sent full-range to them. I've blown a few tweeters that way. If running them active, best to put a cap in series: a cap that is much lower than your xover freq, so it doesn't really affect the tweeter's active slope. Like say a 47 uF cap.
_
Andy Wehmeyer :
Yes, this is right. You shold ALWAYS protect your tweeters from damage with an additional cap. I've used 20uF, but 47uF will work too
______________________________________________________________

Andy Wehmeyer :
A passive network between midrange and tweeter is sufficient, but for midbass, i'd suggest an additional amplifier with an active filter. For this setup, I'd simply add a 4-channel amplifier and use half of it for the mid/tweeter and the other half for the midbass. If you're using a center channel, the time alignment for left and right is nearly inconsequential, since the left right and center steering nearly eliminates the need for the phantom center, which is what TA provides. 

The amplifier channels are designed to drive 2 ohms, but theyt are not bridgeable

Certainly crossing the mids over lower than 1k is fine--the idea is to use the drivers in their piston ranges (where dispersion is wide). I also think that the rest of your system plan is good. So long as the 5" you plan to put in the center has useful output down to around 100Hz, it'll be great. The bass management system will take care of the rest. 

As far as ventilation goes, if you'll use the 20 watt outputs, I suggest mounting this thing under the seat or somewhere that some air will be able to flow. The unit size is about what you've described--I don't have the info in front of me.
______________________________________________________________

cajunner : 
_you have to acknowledge that while the RTA is showing amplitude, there's likely some artifacts very near the same intensity but coming in at a small delay, such that by comparison with the original clock one might be able to determine what's reflection and what's decay....
_
Andy Wehmeyer :
This is a simple gated measurement compared with a non gated measurement. The gated measurement will give you the anechoic response (no reflections). The non gated measurement will give you the total. difference is reflections. This is how MLSSA and all the other analyzers that do this work. However, low frequency resolution depends on the size of the room. In a car, it wouldn't be possible to accurately differentiate between the two below the midrange. Equalizing above that point will be very effective in one tiny spot. None of this is necessary for good sound and is mostly an exercise in technology for technology's sake. Comb filtering isn't nearly as audible or objectionable as people think and that's what the phase dfferences between diect and reflected sound create.

Occasionally, if the stars are aligned, there can be some huge peaks caused by constructive interference, but without a head-tracker and a convolver, they are damn difficult to remove--moving the speaker is the best fix in those cases.
______________________________________________________________

SSSnake : 
_Care to elaborate on the 24 channels (seems like a LOT). 
_
Andy Wehmeyer :
Sure--
3-way in the front doors...tweeter, 3" mid and dual-coil 6"
2-way center...tweeter and dual coil 6"
2-way in rear doors...tweeter and dual coil 6"
2-way in the rear deck...tweeter and 3"
2 10" woofers in the rear deck (IB).

Hmmm...that's 23 channels. I guess I have an extra unused channel somewhere. 
Everything but the subs are driven by 20-watt ICs
______________________________________________________________

cajunner : 
_that's what I was thinking, pick a super high efficiency, ragged response driver and let the auto-eq fix that right up, no more worries about peaks and dips when the MS-8 has got your back...
no more choosing between lower sensitivity, higher cost product that is designed at high cost for smooth RTA, slap in a couple of Whip or Eminence 100db mids and you're sounding like Skaaning on the flip fo' show...
_
Andy Wehmeyer :
Of course, this is a valid method, and you'll likely see much more of this from the OEs as the popularity of electric cars and hybrids increase. It's much cheaper in terms of money and current to use high efficiency drivers than more powerful amps, but optimizing drivers for high efficiency always means reducing the useable bandwidth. You'll see more 3-ways and more small midrange drivers playing narrower bands of frequencies. All of this will be good for imaging too and will make cars sound better. The attendant help will come in the form of crossovers that keep drivers playing in ranges where their directivity is low (sound radiates in all directions). 

Fortunately, a driver has to be really crappy to have a ragged response in the narrower passband where it's most efficient. If you choose this high efficiency route, MS-8 will take care of most of the ugly peaks and dips, but beware of the big peak that you see in the on axis response of all moving coil direct radiating loudspeakers (the kind that have cones and domes). That high frequency peak isn't attenuated as much as the "non-peaky" response off axis. That's makes EQ less effective, because removing the peak in the on-axis response will help to create a bigger hole off axis--basically, the reflected sound won't sound like the direct sound. In a car, that's a bigger problem than in rooms. Crossovers should be chosen to take that peak out of band. This is a big issue for a 6" 2-way, but no issue for a 3-way that includes a little midrange driver. 

Wide bandwidth speakers are the OPPOSITE of the kind of driver that you'd need to implement this kind of design. Be prepared to cross woofers over a little higher and use low pass frequencies for the rest of your speakers that are a little lower than you're used to. 

Hmmm...this sounds like fun. I think I need to find a guinea pig at work and build this car with the cheapest drivers I can find.


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## Tendean17

kkant : 
_I didn't know that this was a fundamental property of all drivers. Could you elaborate? What causes it? And what characteristic of the driver is the frequency of this peak a function of? IOW, can I predict the frequency based on the diameter of the cone, for example?
_
Andy Wehmeyer :
Yeah, it is. It's a function of cone distortion and you can see it in the graphs above. These all appear to be really good drivers and someone has either paid careful attention to this or these measurements are made through a low pass filter. 

The worst of the peaks and the one that doesn't go away off axis is caused by the center of the cone becoming decoupled from the rest of the cone. This property is exploited in the use of whizzer cones, where a small cone is attached to the center to shape and extend the response of that peak. The reason it doesn't go away off axis, is because the actual radiator that emits the sound is a small part (smaller diameter) of the cone that has much lower directivity than the whole cone. The stiffer the cone, the higher the frequency and the higher the Q of the peak. If the cone is more compliant (like a polypropylene cone) the lower the frequency of the peak and the lower the Q of the peak (wider peak). The size and weight of the coil and former affect this too. A heavy coil will cause the center of the speaker to decouple at a lower frequency and a larger diameter coil will increase the size of the secondary radiator. This is one of the reaons that sometimes you'll find really high end 6" midranges have small coils. It's to tame this high frequency problem. The trade off is thermal power handling. So, is a big coil better than a small one? Not necessarily--depends on the intended application.

This is why so many inexpensive car audio speakers use PP cones. It's easy to make the speaker sound good, especially in cars, because the floppy plastic cone has a low-Q rise at high frequencies. It's easy to align a tweeter with the high frequency response of the woofer for a generally rising response. In a car, where we hear the power response of the speaker (average of the output at all angles) that rising response sounds pretty flat and it only requires one crossover component--a cap on the tweeter.

Flat response requires that we cross the speaker over lower--before the peak, but that requires a bigger tweeter or a small midrange and more crossover components.

If any of you remember the Infinity Prelude MTS speaker (a home speaker), this is a really good example of one way to get flat response from super-stiff cones. That speaker uses a bunch of 5" woofers a 2-1/2" mid and a tweeter in a sort of expanded MTM arrrangement. The super stiff cones push the peak to high frequencies and the steep crossover slopes eliminate it from the response. The result is really flat response and near perfect directivity index for rooms, but it's expensive because the crossovers have many components, the cones are ridiculously expensive and the additional midrange is required. The marketers decided that we had to use those same cones in car audio drivers but no matter how we tried, we couldn't make it work very well for big 2-way speakers. That series of Kappa speakers didn't sound great and weren't big sellers--the marketers learned a lesson. 

There are many things that can be done to tame this peak and a stiff cone isn't always the best cone. Many pro-sound drivers have concentric rings molded into the cone (see older JBL pro speakers). Those rings are designed to create compliance in the cones to cause the cone to distort in a way that smooths the response at high frequencies--important when you'll use a 15" speaker to make 5-or 600 Hz. This can also be accomplished by varying cone thickness along the profile.

Exponential curves for speaker profiles are also designed to tame this peak, when compared to flat-sided cone-shaped cones. Dustcap materials and shapes can help to tame the peak also. 

Woven cones tend to distort according to the pattern of the weave, and adjusting the weave or the resin used to stiffen the fabric can help to flatten response too. Incidentally, that resin (type and amount) along with the material and the coarseness of the weave is what is used to adjust the compliance of the speaker's spider.

All of this is why simple cone-material stories are often a bunch of marketing hooey, especially when they just indicate that the cone material is stiff. Polypropylene isn't stiff. It's the opposite of stiff and it's chosen specifically for that property (also because it can be made to last a long time in adverse heat and humidity conditions). Laminates can be made to be stiff, but something can also be laminated in between the outside layers to make the cone stuffer, alter the profile or provide damping for resonance. If you read about the bodies of many high-end cars--I think Lexus does this--the body is sometimes a laminate of two layers of thin metal with some damping material in between. This is designed to eliminate resonance and quiet the cabin. 

Finally, a laser interferometer can be really helpful in designing good speakers. We use one. Basically, the designer can take a prototype into the chamber and make a simple frequency response measurement. That will show peaks and dips. Then, he takes the speaker to the interferometer, excites it at the problem frequency and the machine makes a movie of the movement of the cone at that frequency as a wireframe and a heat map. Then, appropriate measures can be taken to stiffen or weaken the cone to eliminate the peak or dip. I have some of these movies from the development of the 660GTi speakers along with some made for some really high-end competing speakers. The movies are huge and I have no idea how I could post them so you guys could see them. The interferometer works on boxes too. You can watch the box flex and add a brace at the appropriate spot to stop the flexing. 

So the moral of the story here is that a light cone driven by a strong motor won't make much bass, but it will be efficient. If that cone is really stiff, it may have flat response in the passband, but it may be ragged at the top of its frequency range. If the cone isn't so stiff, it may have peaks and dips lower in the range of frequencies it plays, but the top end may be smoother. 

If you want to find out the quality of a driver and determine whether it's the right one for your system, look at the frequency response curve. It's the only way to tell. Reading about materials in marketing documents isn't helpful (and, in fact, it can be seriously misleading), unless you know what those materials may require in additional stuff. A speaker designer can look at a driver and tell in a few minutes whether the appropriate measures have been taken to provide flat response, but even he won't be able to tell whether the measure have worked without a response curve.

I know, I know...ask for a quarter, get a dollar...


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## Tendean17

DS-21 : 
_Audyssey claims, though, that their taps don't have a linear distribution. According to their website, the MultEQ XT has 8x the resolution in the bass than above the bass.
What that means, honestly, no idea here. I'll defer to you guys.
_
Andy Wehmeyer :
I'm not a DSP engineer, so I'm going to keep this on a really basic level so I don't get Lycan's hot poker of truth in the a$$ again. 

There is a fairly recent development that makes it pretty easy to divide those taps across frequency bands, perform separate convolutions and then connect the bands together again. If I'm not mistaken, it's often referred to as "Fast Convolution". We're working on another processor that would use this technique for an even simpler device. There's nothing inherently wrong with using multitap FIRs, so long as compromises are managed in a way that keeps cost and latency in line. To be blunt about it, the method doesn't matter so much as the result. For all DSP, the algorithm is much more important than the device on which it runs and on which tools are used by the algorithm. The IC is the hardware, the filters are the tools and the set of rules (the algorithm) by which the device decides how those tools are used are the real meat of any DSP-based solution. The best way to determine the appropriateness of the solution is to analyze the result of using it. If the result falls short, then an analysis of the algorithm, the the tools and the choice of hardware can be useful in designing something else or changing the design. 

The day that someone tells me that the pins on a TI 7xx have to be gold plated in order for the product to be considered high end might be the day that I look for work in another industry.

Hmmm...maybe I should be careful about what I write... 
______________________________________________________________

Andy Wehmeyer :
No fuss created. Thanks for the clarification. I'm happy that someone can provide better info when I'm wrong. Sometimes the long tail of information that never goes away is unfortunate because we can never be smarter than the stupidest thing we've ever written...
______________________________________________________________

rain27 : 
_Andy, What is your opinion on the lowest frequency a tweeter should play at when installed far from the midbass in a 2way set up? There is some debate that a tweeter should not be played lower than 4k if the mid is low in the door and the tweeter is in the sail panel, a pillar, or dash.
When setting the xover on the MS-8, I'd like to what limits to be mindful of.
_
Andy Wehmeyer :
Depends on how big the midbass driver is. If it's a 6", then 2kHz or even lower is helpful in trying to keep the low pass for the midrange as low as possible so it won't be used where the dispersion is narrow. That'll give you better similarity between the on-axis and off axis frequency response. If it's a standard 1" tweeter driven by lots of power, then that's not a wise choice because you'll probably blow it up. Choosing the crossover is a matter of driver safety first, directivity and a match to the next smallest driver second, and trying to shape the response third. IF you have an EQ, then that's the better tool for response shaping if moving the crossover around compromises the first to criteria. 

I think the winner of the debate mentioned above should be the person who has most vehemently argued against the suggestion.
______________________________________________________________

Andy Wehmeyer :
When you use MS-8, it may be helpful to adjust your perception of how best to use a crossover. In conventional systems, we often use the crossover to get the smoothest response possible before applying EQ. If you have an RTA, this is probably the first part of the tuning process. The most important part of choosing the crossover is to make sure that you set high pass filters so that the drivers are safe from too much bass. Then, it's a matter of choosing the precise frequencies and slopes to get the best blend between the speakers according to the microphone while setting the levels of the adjacent bands. 

With MS-8, you don't have to do all of that. Just set the crossovers for steep slopes to minimize driver interaction and choose frequncies that keep the drivers safe.

For example, a couple of days ago we put one in a 2000 BMW 3-series with the old amp that has analog filters built into the amp. All we did was add a simple capacitor to the tweeters in the front and rear and connected the tweeters and small mids to the MS-8. We used separate channels for the front midbass drivers and a pair of chanels for the subs. Worked great. No need for some complicated passives between the mid and the tweeter.

MS-8 won't fix a stupid system, though. If you use an 8" midbass in the door and a 1" tweeter in the top of the door, it won't fix the problem you'll have at the crossover point due to directivity issues, but neither will a huge collection of tunable filters or overlapping crossovers, no matter how cool the PC interface may be. Bottom line is if you build a competent system, MS-8 will make it sound better than 99 percent of the other processors available whether they have an autotune or whether you or a real acoustician adjust the EQ.
______________________________________________________________

michaelsil1 : 
_I have another question. 
I read in the manual that JBL highly recommends using 24db slopes would I run into any issues using (Phasing, SQ) 12db slopes?
_
AdamS :
I'll give you the beginning of the answer and then you can tell me if your eyes are glazed over or if you want to know more...
LR or Butterworth filters in the acoustic domain don't add well for 2nd order. In fact, they cause a null. This is easy to fix. Either the lowpass or the highpass signal needs to be flipped.
So let's suppose you have L/R (2-way), cutoff of 80Hz, 1K
and a center cutoff of 200Hz, 1-way
Then for L/R....
0-80 negative polarity
80 - 1K positive polarity
1K and up negative polarity
This in and of itself would be fine.
But now add in your center.
0-200 negative polarity
200 and up positive polarity
Now let's map these together.
0-80 L and R negative, C negative
80 to 200, L and R positive, C negative (this isn't good)
200 to 1K, L and R positive, C positive
1K and up all positive
So basically in this example from 80 to 200 you get out of phase stuff. 
If you have a 2 way system or if your speakers are all the same, this will be OK. We take the Lowest L/R driver as the positive reference and flip the rest as needed to avoid nulls.
Lesson here, unless you really have a need for 2nd order, try not to do it. It's the only way I really know how to make things sound poorly, with or without MS8.


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## Tendean17

Bikinpunk :
Alright, I did some more driver swapping tonight in my buddie’s car (he’s a member here so he can chime in if he sees this).

We tried wavecor tweeters, his PPI tweeters, and a set of h-audio trinity’s running full range from 300hz +. We swapped the drivers out, and tried them in different angles, re-running the calibration each time.
Every time, there was a different end result. With the PPI’s, the system was just too harsh and the imaging was crap. The trinities were aimed on-axis for their testing and sounded great. Imaging was much better and center was dead center. The wavecors were crossed at 3000hz and sounded great as well. I won’t get into the things we noticed. The point is that each change of the system resulted in a different system response. I’m not talking ‘critical listening’ differences; I’m talking driver characteristic differences and glaring response differences. Simply swapping tweeters and re-running the setup resulted in a better center image. 

What I’m trying to say here is simple:
Installation does still play a role in the final output even with the ms-8. Something I think many people who are using this unit may not realize. (ie: I hooked it up to my system and it didn't sound awesome like you said it would). The ms8 will not, and does not make every system “sound the same”. I thought it would. I experimented and found that to not be the case. It’s up to you to realize your car’s full potential: don’t rely on a processor to do it all. 

It only goes to show that install plays a huge role, no matter what processor you use. The ms8 simply makes it easier on you to hear the differences. You can’t have a shoddy install and expect the ms8 to be the only answer to fixing your problems. You’ll still need to play around with angle and location to see what works best. 

Take advantage of the ms8: use it to experiment. Try things. 
This whole idea of “yea, but you can’t tinker anymore” is complete BS. You can still tinker. I’d argue that it’s now much easier for someone to tinker and realize how the differences in install and drivers affect your system’s response. Because of the ms8, I’ve been able to have more fun with trying new drivers. Back with my old processors, it was much harder because you really had to re-tune everything. I can’t guarantee that the ms8 is going to give me the optimal tune everytime, but I think it sure takes a lot of the guesswork out. So much so, that I’m now switching things, running the setup, listening, taking notes, and switching again. 

To the people who own the ms8: realize and harness its potential! You have a great tool at your disposal. Don’t be complacent… take advantage of this toy to learn and experiment.

- Erin 
______________________________________________________________

Andy Wehmeyer :
OF course it can't fix everything. However, if you're finding huge differences when you switch out drivers, then the differences are most likely due to frequency response differences between drivers and sensitivity differences, which may cause you to adjust the levels of the sweeps. If the "image is crap", then the sweeps are too loud. Even the crappiest speakers should provide a decent image, so long as they cover most of the audible bandwidth. The differences between one driver and another shouldn't be big differences in frequency response, as this is what MS-8 fixes. Non-linear distortion, which includes bottoming, odd order distortion caused by coil out of the gap, and even order distortion caused by suspension non-linearities or dramatically different flux profiles above and below the gap or other stuff may be audible and will be the difference betweenone speaker and another. IF the frequency responses of the speakers vary so much that the differences are outside of the 40-or-so dB that MS-8 has to use in tuning, then those differences mnay be audible as well. VERY high-Q response anomalies may not be EQed either. So, yes, some differences will exist. What makes MS-8 cool is that it eliminates many of the inconsequential differences.

Erin, I didn't misunderstand your post. You're right on the money. Like you, I just don't want people thinking, "well, MS-8 didn't fixmy problem, so it must be defective" if the problem is one that can't be fixed by EQ and level matching.
______________________________________________________________

Andy Wehmeyer :
Yeah, you can't just throw some drivers in the car in a shoe box or two, hook up MS-8 and expect to get great results. One other thing to remember, especially for DIYers, is that speaker sensitivity makes a big difference in where input sensitivity controls have to be set. I keep writing that setting sensitivity to about 2V onall the amps is righ, but if you choose some midbass that's 93dB at a watt and a meter, a midrange with a giant peak at 2k with a sensitivity rating of 90dB and a tweeter with sensitivity of 82dB, then the gains will have to be set appropriately. 

The car contributes more to the system's frequency response than the speakers do, and the car doesn't change when you replace drivers. Basically, MS-8 has to scale everything to set levels. If your midrange has a 20dB peak at 2k and that's the tallest peak, everything else will be scaled as a result. The window is big, but it's an algorithm. It makes decisions based on a bunch of rules and those rules are written assuming a reasonable system. So long as the system isn't a basket case, MS-8 works great. If your system is a basket case, then it won't. The difference between a basket case with an autotune and a basket case with a toolbox and a tuner, is that the tuner can look at some huge problem and go after a fix that isn't EQ-related, like choosing a different driver, a different location for the driver or a differnt crossover frequency. Of course, MS-8 can't do that. IF it could, we might have named it "Midas". 

IF you're starting from scratch, just build a simple system and put the speakers in the stock locations, especially if you'll have a center channel. If you already have some custom thing going on, you may have to make some adjustments in the way you've managed compromises in the past to get great results with MS-8. Things like line drivers, additional EQs in the signal path, fiber optic signals, mono rear fill, 4-way all-active systems and balanced line connections are all things that may raise compatibility issues. That doesn't make them worng or make MS-8 wrong, it just means they may not work well together. 

I always try to be straight with you guys and one thing I can say for sure is that many of these things that are added as "features" to traditional gear often include outlandish claims of performance enhancement or some other benefit in the interest of distinguishing just another amp from other just-another-amps or just-another-speakers. Most of it has some technical merit, but the merit may never be experienced because the benefit appears outside the audio band, because the benefit overcomes a technical problem that isn't audible (and certainly isn't annoying), or because the benefit is BS but can't be adequately disproven because it's designed to appeal to one's emotions or to dupe you into believing that there is merit by making the signal louder and claiming to make it "better", "more transparent" or my favorite: "effortless". Anthropormorphization is damn difficult to overcome once people are bought in to the hogwash.


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## Tendean17

*The Target Curve for JBL MS-8
* 
Andy Wehmeyer :
The target curve for MS-8 is remarkably similar to the frequency response of a speaker with an ideal directivity index for listening in small rooms. So, if that means that it's designed for a reflective environment, then so be it. Horns don't eliminate reflections, but they do eliminate SOME high frequency reflections from boundariesadjacent to the horn's mouth. 

MS-8 is definitely designed to flatten the midrange and the transition from bass to midrange is designed to locate the bass in the front of the car. If you like tons of midbass, you can always put that back with the 3rd octave EQ.

One thing is for certain, if the sweeps are too loud, what you've described as no midbass will certainly be the case. If the first set of sweeps are too loud, there won't be a center image. The first set of sweeps set the channel delays. If the second set of sweeps are too loud, the system won't EQ properly. So, if you have a good center image, that indicates that the first set of sweeps (without the subwoofer) were at an appropriate level. If you have a good center image and a bad EQ, then the subwoofer sweep is too loud. This is a common mistake, because the sweeps shouldn't be loud at all. 

The attack that you like so much from horns is, in fact, usually a result of big, high-Q peaks in the midrange and better dynamic performance from the compression driver. There's nothing in MS-8 that will diminish the dynamic range--there's no compression used in the algorithm. MS-8 will tame those peaks, but depending on thier distribution, it may group some of them together and tame them with a single lower-Q filter. This may be what you don't like. Additionally, if you're not using additional tweeters with the horns, MS-8 won't provide the huge boost at high frequencies that is necessary to have highs in the car without additional tweeters. 

MS-8 was definitely NOT designed with horns in mind, since the vast majority of cars don't use them. Many horn implementations require a different solution to the standard compromises that are part of building good sounding cars. Depending on your setup and yor tuning abilities, a horn-based system may be better served by a manual EQ.
______________________________________________________________

Andy Wehmeyer :
The additional low pass filter at 90Hz that you use is a workaround for the fact that increasing the sub level increases the acoustic crossover frequency between the subs and the midbass. You've discovered this through hours of listening and tinkering. It's a one-time fix that you've implemented as a compromise. The shelf filter is also proprietary, and only available in MS-8 (although someone else could write the math to make it happen in another processor), and it boosts below 60Hz but NEVER above 160. The slope of the shelf is adjusted as the level is adjusted. It's similar in performance to your additional filter, if the filter were adjusted automatically when you adjusted the level to maintain your crossover frequency and overall response shape

The target response is fixed. The autotune EQs to match the target. If you don't like the target, you adjust the sound using the 31-band EQ. It's not exactly done the way Mike explained it, but the end result is the same. 

There's no need to plug in some high-end microphone. The reason that high end microphones still exist for measurement (and I'd be willing to bet they won't exist for much longer) is that before computerized test equipment, the accuracy was only as good as the flatness and bandwidth of the microphone. Now that analysis is done as software, the hardware isn't so much of an issue, provided the flaws are linear. The microphones that come with MS-8 are good panasonic-type electrets, which are the ones that are used in many other measurement microphones. MS-8 includes a mic correction filter, that makes them measure flat, despite their being mounted in a pair of headphones cases. Plugging in some high end mic is unnecessary and would result in poorer performance. The only advantage might be the ability to make the measurements at ridiculously high levels, but that's just not necessary.

Yes, you can tweak the crossovers if you want, but you MUST run the EQ again after making those adjustments. Fortunately, that only takes a few minutes. You'll find that there's less need to set preposterously low crossovers for midbass, midrange and tweeters with MS-8. 

I'll provide an ETA when the rest of the debugging is underway and when I have a date that we're sure not to miss

The EQ and the rest of the processing in MS-8 can't fix driver distortion and fixing non-linear distortion with DSP is still very uncommon in consumer devices (although many folks are working on it). Certainly, great Eq CAN make the difference between a good speaker and a great speaker much more difficult to hear, but there will always be room for great speakers--especially if they are to be driven with a lot of power. In my estimation, that's the first and best reason to replace speakers--so you can add more power. The opportunity for substantial improvement in most playback systems by replacing drivers with like drivers is coming to an end. So long as the system plays loudly enough, replacing drivers will soon be like using high-end wire...

BTW, I've done a Richard-Clark-Amp-Challenge thing with speakers in our sound room. The very small difference in the sound (similar sized woofers and tweeters, mounted on a flat baffle in the same way) once the speakers were EQed so they had the same response, wasn't easily perceived my most listeners--until we played them loudly.
______________________________________________________________

Tendean17 :
I think JBL MS-8 use the same target like this ..
http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/11579-flat-response.html



Andy Wehmeyer said:


> OK. Sorry for the delay. As a matter of review and to redirect this thread a bit, I've pulled the following from an earlier post:
> 
> _So, there are a couple of basic ways around this reflection thing in cars. One is to try to minimize them and the other is to "spread the chaos around". Minimizing them is damn difficult if you want to have a car that can be driven. Spreading the chaos around simply means that we try to make all the reflections have similar frequency response so we can EQ them and the sound of the speakers using the same filters. Using the speakers where the dispersion is wide is the way to do this. _
> 
> _Using horns and big diaphragms for "pattern control" is the way to minimize the reflections from adjacent boundaries, but those adjacent boundaries are responsible mainly for altering the frequency response and not the image. Image narrowing and causing the car to sound like a car is mostly caused by reflections of right channel information from boundaries near our left ear and reflections of left channel information from surfaces on our right. This crosstalk partially destroys stereo, as each of our ears hears both speakers and the arrival times are within 20mS. This is worse in cars than in rooms, because the surfaces are closer. That means the intensity (loudness) of the reflections is greater and our perception that they and the initial sound are the same is greater. This is what makes a car sound like a car rather than a much larger space. This condition is what "Ambisonics" tries to fix. _
> 
> _I've tried both of these routes to great sound and I find that the "spread the chaos around" method is the most straightforward and because the conditions in the car make this much easier. The cheesy drawing below makes this a little more obvious, if the car is compared to a room. _
> 
> _
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> _The first rule of equalization is that you can't put energy back into a null caused by destructive interference in the acoustic system. You can remove energy from a peak caused by constructve interference._
> 
> _The second rule is that high-Q (narrow) peaks and dips are less audible than low-Q peaks and dips. When we listen to music, our ability to perceive high-Q peaks and dips is further decreased because the chances that a particular sound will happen at precisely the right frequency, thereby energizing the high-Q peak or dip is reduced. In essence, this means that there may be no need to smooth the high frequency part of the comb, but the low frequency part of the comb, particularly the first (lowest-frequency null) is a problem. Plus, many listeners like the way the top of the comb sounds, because it adds a sense of width by screwing up the phase between the speakers and drawing our attention to the locations. This is very hard to hear in the frequencies that tweeters play, but a bit easier, lower in the midrange. _
> 
> Patrick's method is different than my method and both work. Patrick's goal is to control both frequency response and directivity (through narrow passbands and pattern control--(horns) and using speakers in the range where they beam) and the method I suggest is the opposite. The reason that they both work is because, as I've suggested before, we don't hear the reflections as separate events. Patrick attempts to eliminate adjacent boundary reflections, and I suggest simply EQing them along with the direct sound.
> 
> It's important to note, that neither method will eliminate the reflections from boundaries close to our ears, and those reflections are the ones that make a car sound small--those reflections contribute crosstalk (left sounds at our right ear and right sounds at our left ear).
> 
> OK, so if you're following me, the basics are that we have to have a right and left speaker system that covers the band of frequencies from the crossover point between them and the sub and 20kHz without huge holes in either the on-axis response or the off-axis response. Of course, the off axis response will exhibit gradual attenuation as frequency increases, but it shouldn't have big peaks or dips near any crossover point. Below is a nearly ideal frequency response and directivity index:
> 
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> 
> Obviously, the red curve is slightly better than the blue one. For the speaker in the graph above, we use a waveguide on the tweeter to match the directivity of the tweeter to that of the woofer at the crossover. A similar curve (a directivity index that's reasonably flat with no peaks or dips) can be achieved by using multiple drivers in the regions where they DON'T beam. This is why I suggest a 3-way system in the front doors.
> 
> The frequency response plot below is one for a 2-way component system that doesn't include any measures to match directivity between the drivers. The crossover point between the mid and tweeter is too high (the mid starts to beam off axis). There's no directivity index plotted here, but it would include a peak in the region where the off-axis response shows a dip.
> 
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> 
> OK, so now that we've placed a great deal of importance on getting the speaker system right to begin with, here's an example of why that's all good system design practice, but in the end, doesn't matter nearly as much as it might seem. It is important to be sure that the entire bandwidth is covered competently, because we can't put energy into a system if there's no source for that energy--if your speaker system has a big hole at the crossover, you can't get it back.
> 
> Below is the near-field respone of the OE speaker in the door of a Mini Cooper. The measurement was taken about a half inch form the grille. Despite the dip at 1k, the response isn't too bad. BTW, I didn't investigate the cause of the dip
> 
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> 
> If I were building this system, I'd add a 3" mid and cross the 6" at 1kHz. The OE system doesn't include a low pass on the 6" and includes a small tweeter in the top of the door. Anyway, if I close the door and place the microphone at the driver's listening position, this is what the response looks like:
> 
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> 
> Nice, huh? What's the difference? Reflections and a tweeter. Good luck trying to eliminate all of that--no matter what you do, you'll never get back to the previous graph. The stuff below 1kHz can't be eliminated by anything other than dramatically changing the shape of the interior surfaces and the size of the vehicle. Between 1kHz and about 10kHz, adjacent boundaries contribute to the mess. Above about 10kHz, adding foam and carpet here and there might tame this somewhat, but the benefit isn't worth the effort.
> 
> Fortunately (or unfortunately) the response above is what we hear and it can be adequately equalized. Below is the target response I suggest:
> 
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> the big problems at lower frequencies have to be fixed. It won't be possible to put energy back into the biggest hole, so the peaks will have to be reduced to match.
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> 
> At this point, looking at a lower-resolution graph may be helpful--we don't want to be distracted by all of that high-Q stuff at high frequencies.
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> . Here are the steps, including selection of a high pass filter frequency:
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> 
> Of course, this can't be done with a 31-band graphic EQ and that's why those aren't useful. It also can't be done by moving speakers, changing the aiming, swapping the speaker for something better, adjusting the crossover point between the mid and tweeter slightly, adding damping material to the doors, or anything else. EQ is the only thing that will help.
> 
> This is why I suggest the method I suggest.
> 
> TA should be set first, especially if you can align the tweeter and mid separately. After TA, set your EQ according to the process above. Once the left and right have been EQed so thay have the same response and the arrival times match, add the sub. EQ the right with the sub. Then turn the right off and EQ the left with the sub. Then, turn on both channels and listen. If you need to make further adjustments, be sure to EQ right and left equally--you're just shaping the response now and you can't equalize frequency reponse problems that appear in the measured response of both channels, measured at the same time (see the lengthy discussion of comb filtering in the previous post). In fact, what you see on the RTA won't even look like what you hear, so don't pay much attention to the RTA of both channels playing at the same time for any frequency above about 150Hz (the region where the sub contributes).
> 
> Also, moving the microophone around a head-sized area will help you determine whether to fix the high-Q peaks at higher frequencies. If they change or go away as you move the mic, don't worry too much about them unless they annoy you when you listen to music. Then, pick the annoying one and get rid of it.
> 
> BTW, we have a new 2-channel auto EQ algorithm that does precisely what I've suggested and it makes even this Mini Cooper with the factory speakers sound GREAT.


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## Tendean17

Andy Wehmeyer :
Oh, and for wat it's worth, the amount you turn your head will affect the high frequency EQ slightly. If you turn your head really far, there will be more high frequency masking (indirect path to the opposite ear and more off axis to the ear closest to the speaker being measured). There will be NO difference between the tuning below 1k. It's really not that sensitive to the head turning thing.

The most important things during calibration are the right crossover between bass and midrange and the levels of the sweeps.
______________________________________________________________

Trigg007 :
_I'm not overly concerned with response the curve options. However, what you claim is not clearly stated in the manual. It'd be nice to confirm though...
My primary concern is about the crossover options. What types (Butterworth/Linkwitz), available slopes & crossover range/setting options. I spent 20 or so minutes on the phone with JBL tech support in an attempt to have my questions answered to no avail. All they could offer was wording similar to the manual. No disrespect to JBL, but I'd like to know before making my purchase decision. All the tech person could offer was a "call back in 2 weeks". Maybe Andy can "chime" in 
_
AdamS :
1st order: Butterworth
2nd order: LR
3rd order: Butterworth
4th order: LR

LR doesn't exist for 1st and 3rd as it is a squared Butterworth.
Crossover frequency resolution is in resolution of Hz.
if you have a sub
subsonic : 20-50 Hz
sub/front: 20-200 Hz
if you don't have a sub
sub/front: 20-100 Hz
others
Front Lo/Mid: 100Hz-10Khz
Front Mid/Hi: 200Hz-10KHz
Center highpass: 50Hz-10KHz
Center Lo/Hi: 50Hz-10KHz
Side highpass: 50Hz-10KHz
Rear highpass: 50Hz-10KHz

There are restrictions... ie complementary lowpass and highpass must be at the same frequency. You can't equalize the system with crossovers by forcing bumps or dips. Use the 31-band for that.
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trigg007 : 
_great...what about a 3-way set-up?_

AdamS :
It's included. Here's an example. Suppose you have a left (3-way), right (3-way) and sub.
subsonic : 20-50 Hz 
sub/front: 20-200 Hz (between sub and front)
Front Lo/Mid: 100Hz-10Khz (between low and mid)
Front Mid/Hi: 200Hz-10KHz (between mid and high)
Visually (from a low frequency to high frequency perspective):
-Sub-Low-Mid-High
There are crossovers at each of the -.


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## Tendean17

trigg007 : 
_I hope you're right; can anyone confirm? 
Also, is there anything else available (literature) with more detail in what you can/can't do with the MS8. I've read both the MS8 manual and the Bit1.1 manual. To me MS8 seems like "set it & forget it" versus the BIT.1 being more of a nightmare to tune for those of us who just want to enjoy the music. Don't get me wrong, according to the manuals, the Bit1.1 appears to have substantially more processing power, or atleast the manual is considerably more informative (IMO). What are the crossover options? Can the time correction be tweaked/changed versus the autotune feature, etc...
_
Andy Wehmeyer :



Andy Wehmeyer said:


> Yes, you can't change the target function but you can retune with a second 31-band EQ. Since the channels will already have been matched and tuned separately with the auto EQ, there's no need for separate right and left channel EQs for retuning. You can simply draw the adjustments you want to make and those adjustments will be applied equally to all channels. It works great.
> 
> I just remembered I have some documentation on the EQ 31-band EQ that you may find interesting.
> 
> Most graphic EQs don't give you what you may think you're getting. depending on the Q values that are chosen for the filters, the sum of adjacent band adjustments may be flat or they may have little dips in between the boosts. Many of them have qs that are wide enough not to produce those little peaks and valleys, but then the sum of the adjacent filters produces far more boost or cut that you might expect. Here's an example below.
> 
> In this EQ, boosting one band provides an expected response:
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> If we continue boosting adjacent bands, this is what you get:
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> In this example, boosting a bunch of bands gives you twice the boost when the results are compared to the slider controls.
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> In the example below, clearly what you get is not what you may have intended:
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> So, when you choose an EQ and try to use it, it's helpful to know something about the design. This detail isn't always provided and it can make tuning a real pain in the butt. A graphic EQ can be designed with higher Q values to make the adjustment bands narrower, but there's always some error.
> 
> MS-8's 31-band graphic works differently. When you adjust bands, the EQ adjusts the adjacent bands automatically to match the response to your intended response. In the three examples below, the little green circles represent the slider controls. the red line represents the output of the EQ and the automatic adjustment of the adjacent bands is represented in the top graphs.
> 
> The three examples below are response shapes that are very difficult, if not impossible, to make with any graphic EQ I've ever used--digital or analog. I can't even imagine the amount of time it might take to implement these with an analog EQ.
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> In this one, there's a little wiggle between 200 and 500 Hz, but it's less than 1dB.
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> So...with the autotune that "fixes" the car, and this EQ which is a pretty accurate drawing tool, you ought to be able to make the car sound great easily without a bunch of hassles.


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## Tendean17

AdamS :
Andy's data is a little old. We reduced the minor ripple > ~12 KHz even further.
http://www.diymobileaudio.com/forum/1044261-post2659.html
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quality_sound : 
_Exactly. The MS-8 is going to his it's target curve every time. It might change slightly, but it's better to run it once and then draw in YOUR target curve and let the MS-8 make it's changes and be done with it. With the MS-8 all you really need to know is the final curve you want.
_
Andy Wehmeyer :
Right. The curve that MS-8 hits is one I've used for 25 years to make most customers happy. the beauty of the deal is that the hard work of eliminating peaks and dips, getting TA right and balancing the crossover vs. EQ is done for you. Then, all you have to do is fiddle with an easy tool designed to make fine tuning easy, rather than using that tool (31-band) do do the hard stuff. 31-bands isn't sufficient for the hard stuff.
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Andy Wehmeyer :
There are two ways to eliminate the peaks and dips that are caused by reflections--comb filtering--from the measurement: spatial averaging and spectral averaging. We use both. The measurements are averaged spatially and then the response is averaged spectrally when the EQ filters are applied. The differences between the different head angles are small, but if you turn your head so far that both speakers (weeters mostly) are far off axis in measurements 3 and 4, you'll have more high frequency in the resulting curve. A big difference in the placement of the mic for all 4 measurements (tall person vs. very short person) will result in different listening experiences. We remove comb filtering from the measurement because we don't hear it and EQing to remove the high frequency part of the comb is unnecessary and results in bad sound. 

Through the course of developing MS-8, some of the DSP guys have developed a spectral average that performs almost as well as the spatial average (95% or so), and that alogrithm will appear in a much simpler product one of these days. It only requires a single measurement and is designed for a very specific (but very popular) use case.
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Andy Wehmeyer :
The auto EQ is separate left and right for front, sides and rear, separate for center and sub also. Then, the 31-band changes the curve for all, since they're already matched.
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cajunner :
_something I'm still fuzzy on, is what frequencies are targeted for manipulation by the auto tune, and whether the addition and subtraction of magnitude-related filters, is also then treated to time alignment for proper phase, or vice versa. I believe this is how MS-8 does it, but the Pioneer might not, relying on filters only?

also, if you use an equalizer function that picks more frequencies in the bottom and middle of the spectrum, (you've only got 500 or so bands of adjustment, so out of 20,000 different frequencies...) will it lead to better control of the frequencies that control width(ITD), and leave the height manipulation(IID) underserved?

so, depending on whether your install needs help more in one area than another due to relative speaker placement, one might be more useful than the other?_

Andy Wehmeyer :
MS-8 uses 8 filters that can be any shape (not bound by the typical frequency, magnitude and Q values common to standard parametric EQ) and the entire frequency range is divided into 8 sections. This is applied to a spatially averaged and smoothed curve. Rather than the resolution of the EQ being defined by the number of filters, it's defined, basically, by the spatial averaging and the smoothing. For typical FIR (512, 1024, etc) multitap filters, the resolution is defined by the number of taps (512, 1024, etc) While that might sound like really high resolution, the taps are often distributed over the frequency range in a linear fashion rather that logarithmically. That means that half of the filters are applied between 10K and 20K and half below. That's a problem because a 512 tap filter only provides 40Hz resolution and you need better resolution in the bass and midbass. Without a spatial or spectral average, however, the FIR filter just fills in dips and attenuates peaks. This is great for speaker EQ, but not so great for room EQ in a really reflective environment, EQs that operate this way often attempt to fill in high-Q nulls caused by reflections. This is a no-no and it's one of the reasons that building a great room EQ isn't as easy as just adding resolution to a standard multi-tap arrangement. 

There are tricky ways around this and the tricks all have different names. One way is to divide the spectrum into several bands and apply FIR filters of different lengths to the various sections. A low-power 256 tap filter applied to frequencies below 200Hz would give better than 1Hz resolution for the bass, for example. Then other filter lengths could be used for other ranges and then the signal could be combined before the output. 

I have no idea what method Pioneer uses for their autotune. The Audyssey algorithm has some form of redistribution of the taps for better resolution at the low frequencies. The quality of the EQ's performance isn't necessarily related to the KIND of filter that's used. Rather, it's related to HOW the filters are used. All have their benefits and drawbacks


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## Tendean17

*Phase and Frequency Response*

Andy Wehmeyer :
OK, the sound we hear in cars and rooms includes reflections, and those reflections also create comb filtering, 
which change the frequency response and change the image, just like the two independent speakers in the screenshots above. We can't time align reflections to get rid of the constructive and destructive interference. For the rest of this, remember that reflections from nearby surfaces have short PLDs and from far-away surfaces have longer PLDs when compared to the initial sound fro the speakers which cuts a direct path to our ears. 

For an even more detailed picture of what happens, it's important to consider speaker directivity. Adjacent boundaries will produce reflections for speakers at frequencies where the dispersion is wide, but not where the dispersion is narrow. The angle of incidence equals the angle of reflection, and that's anpther thing to take into account when considering how all of this interacts. We don't have to be concerned with reflections until the sum of all of them reaches our ears, because that's the only place where we hear their sum. 

So, there are a couple of basic ways around this reflection thing in cars. One is to try to minimize them and the other is to "spread the chaos around". Minimizing them is damn difficult if you want to have a car that can be driven. Spreading the chaos around simply means that we try to make all the reflections have similar frequency response so we can EQ them and the sound of the speakers using the same filters. Using the speakers where the dispersion is wide is the way to do this. 

Using horns and big diaphragms for "pattern control" is the way to minimize the reflections from adjacent boundaries, but those adjacent boundaries are responsible mainly for altering the frequency response and not the image. Image narrowing and causing the car to sound like a car is mostly caused by reflections of right channel information from boundaries near our left ear and reflections of left channel information from surfaces on our right. This crosstalk partially destroys stereo, as each of our ears hears both speakers and the arrival times are within 20mS. This is worse in cars than in rooms, because the surfaces are closer. That means the intensity (loudness) of the reflections is greater and our perception that they and the initial sound are the same is greater. This is what makes a car sound like a car rather than a much larger space. This condition is what "Ambisonics" tries to fix. 

I've tried both of these routes to great sound and I find that the "spread the chaos around" method is the most straightforward and because the conditions in the car make this much easier. The cheesy drawing below makes this a little more obvious, if the car is compared to a room. 

The first rule of equalization is that you can't put energy back into a null caused by destructive interference in the acoustic system. You can remove energy from a peak caused by constructve interference.

The second rule is that high-Q (narrow) peaks and dips are less audible than low-Q peaks and dips. When we listen to music, our ability to perceive high-Q peaks and dips is further decreased because the chances that a particular sound will happen at precisely the right frequency, thereby energizing the high-Q peak or dip is reduced. In essence, this means that there may be no need to smooth the high frequency part of the comb, but the low frequency part of the comb, particularly the first (lowest-frequency null) is a problem. Plus, many listeners like the way the top of the comb sounds, because it adds a sense of width by screwing up the phase between the speakers and drawing our attention to the locations. This is very hard to hear in the frequencies that tweeters play, but a bit easier, lower in the midrange. 

FWIW, this delay between the channels is used by music producers to provide a sense of spaciousness or a separation of the sound in right and left channels. 

I use impulse response measurements for setting delays. It's important to turn off low pass filters during the measurements, if you do it that way. No need to time align to the sub. 

I usually use 4th order slopes to minimize interaction between the drivers, which are seldom mounted close to each other and to protect them from too much bass.
______________________________________________________________

Andy Wehmeyer :
The out of phase information will steer rear. If you have no rear speakers, it'll disappear. 
L7 works great with stereo recordings and recordings designed to reproduce a space. If the mixologist used a bunch of processing because he fancies himself an artiste and wanted to create some cool effect, then that cool effect will be made even cooler by L7. 
If you want to test this for yourself, download audacity and make a pink noise track. Then, reverse the phase of one channel in the track, burn it onto a CD or load it onto your iPod and play it back. The noise will steer rear. 
Then, record your own voice (or someone else's) and switch the phase of one channel. The voice will appear in the back. You can build a track where the voice will rotate around the car. You have enough info to do that. 
Or, if someone has a place i can upload a track like that, I'd be happy to.
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Andy Wehmeyer :
MS-8 hates one speaker out of phase, especially one of the front midranges or midbass. 
In about 90 percent of cases where people have contacted me about bad sounding MS-8s, especially "no midbass", "center image with no focus", or "near-side bias" this has been the problem.
One of the installation schools and plenty of people who claim that EQ is the devil tout the advantages to running one midrange out of phase. They claim that this improves the center image. It's BS. In most cars with door mounted midbass or midrange, the difference in distance from each of the doors to your ears puts those two speakers out of phase at about 200Hz and at multiples of 200Hz. 200Hz is right in the middle of the vocal range, and singers are often recorded in mono, so they seem to be located center stage. Putting one midrange out of phase when the speakers are mounted in the doors puts 200Hz back in phase, but moves the first out of phase frequency to double the original frequency and multiples thereof. 
The reason that MS-8 hates this is because it uses time alignment and signal steering to overcome the out of phase problem for center steered sounds. Because there's a center channel, equal pathlengths aren't a big deal because the mono information doesn't have to be created completely by the acoustic sum of the left and right speakers. It's sent to the center speaker and attenuated by 6dB in the left and right. An out of phase door mid won't KILL the center, but it will screw it up. Out of phase speakers don't sound the same with MS-8 as they do in a simple stereo system, so they're harder to detect when you listen for imaging, but they have a huge detrimental effect on frequency response. 
In a L7 system. left of center and right of center images are created by the acoustic sum of left and center and right and center. A sound that should appear in between left and center is attenuated by 6dB in the left and in the center, so that the sum appears between them at the proper level. If either speaker is out of phase, it screws this up too.


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## Tendean17

Andy Wehmeyer :
Phase shift only matters in the acoustic response that you hear. At the crossover frequency, it's sufficient to choose slopes that provide a smooth transition in that region. If there's a deep and narrow dip in the response when you measure it with n RTA, then you should choose a different slope or reverse the polarity of one of the speakers (you'll also have to reverse the polarity of the same speaker in the opposite channel)

Right, phase in the passband doesn't matter, so long as no other speakers are playing the same signals. As I wrote above, phase at the crossover matters only if it affects the frequency response and an acoustic measurement is the only way to tell. Don't sweat the WinISD plot for the woofer. Build the box, put it in the car and EQ it. 

The 50 degree difference won't present a problem. IF the yellow trace is the high-frequency driver, it's also important to consider that the output level from that driver ought to be reduced in level, so the sum of the two will be mostly the output form the woofer.
______________________________________________________________

Andy Wehmeyer :
Well, all of that is true and it matters most when we're summing electrical signals. The electrical signal only matters for acoustic purposes since it modifies the acoustic signal. The phase that Adam is referring to is measured on the electrical output. 

The phase between two drivers that must combine acoustically to provide the appropriate response at the listening position also depends on the distance between those two drivers and the listening position. If you have an RTA, you can sort this out so long as you have some way to adjust the phase---hmmm...don't know of any aftermarket processors that allow this to be done manually. So, my suggetsion is to use steeper slopes which minimize the need for all of this work, because the range where the drivers have to be in proper phase alignment is minimized--less overlap or a smaller transition band--call it what you want. 

For speakers mounted close together on a flat baffle (like a home speaker), the rule about electrical filters that Adam has explained loosely translates to acoustic responses because of the position and the proximity of the drivers and the fact that they can often be filtered in a range where their response is flat. In cars, this is rarely the case and the benefits of mounting the tweeters high in the car and the woofers low in the car where they fit outweigh the crossover phase crapshoot mitigation that might be achievable by mounting the speakers closer together.

Use a 4th order setting between speakers and lower orders on the top or bottom of the entire band you're reproducing. There's no need for a 4th order subsonic filter unless your subs are small. I suggest a 2nd order there. If you're using rear speakers, set them at 100Hz 4th order for other reasons that I can explain later. That's a L7 deal and my suggestion will preserve midbass impact and the illusion of bass up front. 
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Andy Wehmeyer :
The out of phase voice should steer to the rear. That's what Logic7 does. 

MS-8 isn't going to get rid of the bass you feel, but it will get rid of bass that's more than 9dB above the rest. This is why I keep saying to turn the bass amp down during calibration and then turn it back up. MS-8 is designed to make it sound like the bass comes from the front, if possible. That can't happen if the bass is 20dB above the rest of the system. If you don't care about the placement of the bass, but you want a ton of it, then take my suggestion. Turn the gain down, run calibration, turn the gain up.
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Andy Wehmeyer :
Out of phase information in the recording will be steered to the rear. In acoustic or direct to 2-track recordings or recordings designed to recreate a live event, this information will mostly be room reflections. Steering those to the rear works pretty well in terms of creating good ambience. The algorithm is similar to PL2 in the steering of signals to the rear, but L7 has some other goodies that make it possible to resolve rear left and right (something not done very well by other algorithms) and another feature that helps to plant front steered images in front. The difference between rears and sides is an additional few milliseconds of delay.
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Andy Wehmeyer :
I just checked out the owner's manual for the DCX 730. In a very basic 2-channel system, the EQ is pretty similar. The 730 allows 7 bands of parametric EQ per channel. MS-8 uses 8 per channel. The difference is that the 730 allows you to use standard frequency, gain and Q adjustments. The MS-8 doesn't allow you to manually adjust the parameters of the filters, but the 8 parametric bands can be ANY shape. That means that MS-8 isn't bound by the traditional frequency, Q and gain parameters. 

MS-8 uses an impulse response measurement to determine the location of the first big peak in that measurement. Then, it backs up until the response is 12dB down and sets the delays for that point. This better approximates the arrival time of speakers that don't provide much high frequency response compared to just picking the top of the peak. The amount of high frequency in the measurement determines the slope of the line, and more high frequency makes the peak more pronounced. Any of you who have tried to determine arrival times with an impulse response measurement have undoubtedly seen this, especially for subs. The impulse looks like a big hump. The initial arrival of sound from low-passed speakers is NOT the top of the hump. Delaying the rest of the system to meet the top of the hump of the subwoofer is unnecessary and just chews up processing power. In fact, it isn't necessary to consider the arrival time of the sub in a car. However, if your sub amp includes some additional DSP that introduces a delay, adding delay to the rest of the speakers manually can be beneficial. 

Since both processors operate at 48k, the resolution of the delay adjustments is the same--that's determined by the number of samples per second. A one sample delay at 48k is .238 inches.

MS-8 follows a set of rules to tune the car. If you tune with the 730 (or any other manual processor) you're still bound by some rules (consider the frequency, Q and gain example above), but not by others. If your system includes something that MS-8 can't deal with, then tuning manually may give you better results. Putting one midrange out of phase to "fix" the center image is one of those things. MS-8 HATES that and will sound terrible if you do this. There won't be any midbass, but the delay adjustment will provide a decent center image, anyway. If you don't like MS-8's target curve and the 31-band EQ doesn't provide enough range to change it to something you do like, then manual tuning may make you happier.
______________________________________________________________

Andy Wehmeyer :



Andy Wehmeyer said:


> OK. Sorry for the delay. I don't use True RTA, but they're all pretty much the same and include the same tools.
> 
> We'll start with a few basics here and most of this isn't my opinion. Rather, it's stuff that can either be verified and has been written about by various people who get paid for this stuff because they're scientists. Some of them are people with whom I work and some is available at the LIBRARY.
> 
> Anyway, cars are full of reflections and there are all kinds of opinions about what to do with them. Since the dimensions of the car are small, the car doesn't create a reverberant field--all reflections arrive within 20mS of the initial sound.
> 
> Second, when the same sound emanates from a particular source and is also reflected from a nearby source, the difference in arrival time and frequency responses of that sound create comb filtering. At some frequency and at multiples of that frequency, based on the difference in distance from the two sources to the listener, there will be destructive interference. The lowest-frequency null is the widest and each subsequent null (as frequency increases) will be narrower than the one that preceeded it. Hereafter, we'll refer to that width as Q--low-Q is wide and high-Q is narrow.
> 
> Here's a screen shot from an RTA to illustrate this. To simulate this, I've set the RTA to show the sum of left and right, and I've delayed the right by 1mS which is about equal to a foot--1.132', to be more exact.
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> In the third screenshot, I've reversed the phase of one channel and it's plain to see that I've moved the null back up, but I've killed the bass response. Switching the phase has put the sound from the two channels back in phase at frequencies where it was out of phase. It's also put the sound from the two channels out of phase at other frequencies.
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> Also remember, that in order for two sources, in this case a right and left speaker, to produce a phantom image in between the two speakers, they must both be in phase. If you sit equidistant from a pair of speakers that are in phase, there's an image. If you swap the polarity of one, there's no image, less bass and you hear the speaker locations. If you're not equidistant, and the two speakers are in phase, then you'll hear a phantom image at frequencies where they are in phase, and no image for frequencies where they are out of phase. In the case of the third screenshot, --a pair of speakers located where the PLD is about 2.5' and one speaker's polarity is swapped, there won't be an image at low frequencies and the bass will suck, there won't be an image at 500 Hz and at multiples of that frequency. The comb filtering causes this image "problem" as well as the obvious frequency response problem.
> 
> For right and left speakers mounted in the doors, the first and lowest Q null happens in the vocal region. Swapping the phase of one channel can dramatically improve the image for a vocalist, but screws up the bass and screws up the image at higher frequencies.
> 
> In the fourth screenshot, I've simulated time alignment by putting the channels back in phase and delaying the other one by 2mS so they match. See, flat response.
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> OK, now that we're clear on this, let's think a little more carefully. When we minimize pathlengths, we simply move the null to a higher frequency. Shorter PLDs place the null higher and higher until when the PLDs match, there's no null. This exercise also shifts the frequency where we begin to hear the speaker locations to higher and higher frequencies. Hmmm...this means that for a sound that includes midrange and high frequencies that should appear in the center, if the PLDs are close, we'll hear MOST of it in the center and we'll hear the high frequencies in the right and left speakers. When we listen to lots of events all playing at the same time, some of it will appear in the center and some on the right and left.
> 
> We're all so used to listening to small PLDs that we hear those errors as stage width, even though it doesn't exist in the recording. It's kinda nice, because small PLDs don't screw up anything for the fundamental sounds in the recording, but do screw things up for harmonics. That condition adds this sense of space --or width.
> 
> OK, the sound we hear in cars and rooms includes reflections, and those reflections also create comb filtering, which change the frequency response and change the image. For the rest of this, remember that reflections from nearby surfaces have short PLDs and from far-away surfaces have longer PLDs.
> 
> For an even more detailed picture of what happens, it's important to consider speaker directivity. Adjacent boundaries will produce reflections for speakers at frequencies where the dispersion is wide, but not where the dispersion is narrow. The angle of incidence equals the angle of reflection, and that's anpther thing to take into account when considering how all of this interacts. We don't have to be concerned with reflections until the sum of all of them reaches our ears, because that's the only place where we hear their sum.
> 
> Finally, in all of this talk of reflections, we have to consider that the sound from the right speaker will be reflected off the left side of the car and sound from the left speaker will be reflected off the right side of the car. This crosstalk partially destroys stereo, as each of our ears hears both speakers and the arrival times are within 20mS. This is worse in cars than in rooms, because the surfaces are closer. That means the intensity (loudness) of the reflections is greater and our perception that they and the initial sound are the same is greater. This is what makes a car sound like a car rather than a much larger space.
> 
> The first rule of equalization is that you can't put energy back into a null caused by destructive interference in the acoustic system. You can remove energy from a peak caused by constructve interference.
> 
> The second rule is that high-Q (narrow) peaks and dips are less audible than low-Q peaks and dips. When we listen to music, our ability to perceive high-Q peaks and dips is further decreased because the chances that a particular sound happen at precisely the right frequency, thereby energizing the high-Q peak or dip is reduced. In essence, this means that there may be no need to smooth the TOP of the comb, but the bottom of the comb is a problem. Plus, many listeners like the way tht top of the comb sounds, because it adds a sense of width.
> 
> FWIW, this delay between the channels is used by music producers to provide a sense of spaciousness or a separation of the sound in right and left channels.
> 
> OK. I'm clicking "sumbit reply" here and I'll continue in another post--this too much work to lose by pressing the wrong key.


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## Tendean17

*Center and Rear Channel
*
Andy Wehmeyer :
Left and right speakers don't have to match the center. that's what the EQ is for. Putting a 6x9 in the center is a great idea. Center channel has to include high frequencies. Yes, tweeters aren't the devil.
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Andy Wehmeyer :
Logic 7 is great in small cars, but rear speakers are required.
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blownrunner :
_I have mids and highs in kickpanels and midbass in my doors. Would it be advantageous SQ-wise to use four outputs (1 to each of the speakers) or two outputs (1 to each side/mids and midbass pair)?
If I use the latter, I would have two additional outputs that I could use for different locations such as side AND rear speakers in addition to subs. Thanks
_
Andy Wehmeyer :
Use four channels for the front. If you decide to do sides and rears, you can run them off of two outputs.
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Andy Wehmeyer :
In my experience there are two important factors in choosing a center speaker and processing in a car. The processing has to be something other than a simple mono signal which is the sum of left and right. That narrows the stage and there's no happy medium between a center that's loud enough to provide a canter image and one that's quiet enough to maintain stage width. 

The best algorithms are those that extract the information that's common to left and right, but that doesn't place distinct left or right sounds in the center speaker. For discreet recordings that's easy. Center is center. For deriving a center, left and right from a 2-channel signal Dolby PL2 or Logic7 can be really helpful. If you'll use a processor that includes either of those, a center channel that is as close to full range as possible is important. A center channel should have a tweeter and ought to be able to go at least down to 200Hz. 100 is better. 
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Andy Wehmeyer :
In any system that uses some active center channel processing, whether it's discreet or a matrix or any other extraction method, the center channel becomes the primary front speaker. Most of the music in popular recordings is placed in the center and it needs to be able to play as loudly as the rest of the front speakers and hopefully with the same or similar frequency response. 

Midbass speakers tend to be less efficient than midrange and tweeters and always need more power. Plus, if you look at the frequency distribution in most popular music, you'll find far less high frequency info than low frequency info. The midbass frequencies are pretty critical and that would be a nasty place to run out of power.

My suggestion? Use plenty of power on the fronts and use the on-board power for the sides and rear. 

20 watts and a small sealed enclosure dn't go together for midbass. You'd be better off installing a seriously efficient instrument speaker and crossing it over with a steep slope at 70 or 80Hz. If you have 5" or 6" speakers in the front, don't bother with a separate midbass. 

It's always better with a center and I'd go with a 4" rather than nothing, unless you don't care at all about the passenger's seat. Then no center is required. I prefer the surround speakers in the sides. That tends to widen the stage a bit, but rear is fine too. 

If you want to bi- or tri-amp the front or center, you can always use outboard amplifiers that include crossovers to achieve that. Side and rear speakers can be driven in parallel from the rear outputs of the MS-8. 

The BMW is set up that way, sort of. The front mids and highs use a pair of pre amp outpus ad a 4-channel amplifier. THe 8's under the seats are used as midbass and are driven by another amplifier connected to two outputs. THe sides and rears are fed by two channnels of MS-8 through another outboard amp. The center uses a passive network, an outboard amp and an output channel from MS-8 and the sub uses the last one. It works great. 
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Andy Wehmeyer :
If it were my car, I'd move the display to the front of that hole and mount the center in the top firing into the windsheild. In either case, I think that's an unnecessary number of drivers. Go with the largest single midrange you can find and add a tweeter (half of a 5" component system would be great). If that's not an option, use a 4" or a pair of mids and a tweeter. If you have a bunch of extra amp channels and an external crossover, biamping is OK. If you don't, I suggest a passive for the center.

I find that the best use of MS-8's 8 channels in a car is:

Biamped front (4)
Center (1)
Sub (1)
Sides and/or Rears (2) 

If you do sides and rears, run them in parallel.

If you use a 2-way speaker system in front, use separate channels for mids and tweeters. If you do a 3-way, use separate channels for the midbass and a pair of channels for mids and tweeters, together with their own crossovers (passive or active). If you do that, cross the midbass as high as you can stand--1k works well so long as they are 6" or smaller. Our ears aren't good at determining the location of sounds from 1k to 3k, and above 3k, level is the most important criterion. This arrangement provides accurate delay measurements and settings for the midbass and will fix the mids and tweeters using EQ. 

Since you'll be using a center speaker, the steering and that speaker will reduce the importance of time alignment for frequencies above the center-channel's cutoff and TA will fix it for lower frequencies using the midbass in the doors

Oh, if you have the additional 3" speakers already, put them in the doors in front of the door handle and cross them over at 1k and 4k. Then put the tweeters in the sail panels and the woofers in the bottom. I've done this in my last two cars and it's great...great, great, great


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## Tendean17

Andy Wehmeyer :
I find rear speakers to be an important part of a system that sounds believable, so long as there's some processing to make them something other than front speakers mounted in back.---Hmmm...wait...the processing currently use makes them front speakers, mounted in back...and some other wacky stuff.
Anyway, yes, use rear speakers. No need to go nuts, though. They shouldn't play anything below 100Hz
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Andy Wehmeyer :
It only matters for UN-EQ during setup. The signal on the setup CD is an MLS. MS-8 "knows" the sequence on the disc and the algorithm is triggered by a pattern of silence, then noise in one channel, then noise in the other channel. In order for it to figure out precisely what the difference is between what it would see if the response was flat between 20Hz-20kHz and what the response really looks like, it has to see the right number of samples. If the clock is wrong and the sample rate isn't 44.1k, the correct number of samples doesn't appear. MS-8 freaks out and part of the algorithm gets confused. We'll have that fixed soon.

Also, I suggest nothing below 100Hz in the rear for Logic7, because the rear channel polarity is part of how signal is steered to the rear. When the signal is steered to the front, the rear channels aren't in phase. Keeping the bass out of the rear channels preserves the placement of mono low frequency signals in the front center. The highpass filter frequency for the rears can be chosen at a frequency below 100Hz, for those who won't use L7

I always suggest splitting up the channels in a three-way front speaker system--a pair of channels for the midbass and another pair for midrange and tweeter. If you'll use a 2-way in the front, then there's no need for that, unless you have the extra channels. 

The system in the BMW included all the stock speakers in their locations. We added tweeters to the rear doors and to the center channel. The tweeters in the rear probably aren't absolutely necessary, but the tweeter in the center channel is. All of those useda simple capacitor on the tweeter--nothing fancy. The rear and side speakers were run by separate channels of a 4-channel amplifier, but were fed with the side outputs of MS-8. Separating side and rear is nice, but we opted to use the under-seat subs as midbass on separate channels instead of doing a full 7.1. It worked great. Subwoofer is a pair of W12GTi woofers in a box in the trunk. 

We defeated the factory Logic7 in the dead unit's menu and used MS-8s L7. THey are tuned a little differently--mosty with regard to the level of the center channel and steering angle computation. I believe the MS-8 version is better for folks who are used to aftermarket systems. The primary goal of L7 in MS-8 is to provide a rock-solud center image in the CENTER of the dash and a sense of ambience (rear) depending on the recording. For those who find the center to be too "center", we've included a level control so you can it turn that down a bit. 
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Andy Wehmeyer :
Left, Right and Center steering helps to minimize the need for generating a phantom image in the center, but it can only work for frequency ranges that are included in the L, R, and center. If you have a big midbass driver in the center and in the left and right, then time alignment of the midbass drivers is less important. If you'll use a smaller center speaker and depend on the left and right midbass drivers to generate a phantom center in those frequencies, then it will be helpful to be able to time align those speakers for a particular listening position. That's the reason that we opted to use the separate channels in Gary's BMW. The center speaker is only a 4" and left and right midbass are 8" speakers under the seats. It works great. Because the center speaker is small, the midbass image is better in the seat for which the optimization is selected, but the compromise between the front two seats was good enough to win IASCA. 

The cure for mystery is investigation. I've spent 25 years investigating this. If you'd like to benefit from those 25 years and additional technical contributions from real scientists who have turned the benefit of those years into a product that works, get an MS-8 when it comes out and just follow the instructions. If you'd prefer to figure out how and where to bury a bone through trial and error, rejecting the canon of knowledge that exists for humans who can read and share information, buy an MS-8 and throw away the installation manual and do a thousand experiments. Or...buy another processor and throw away the manual and do a thousand different experiments. MS-8 won't allow as many experiments as some of the others that don't include any automation, though. If installation and constant tweaking are the "end", then you may be happier with a car PC. If installation and tweaking are the means to the end, then MS-8 and its instruction manual will be the right product for you

If I could find more than 4 installers anywhere in the world who could actually tune a car to sound good, then auto-tune wouldn't be so important. Plenty of folks from other companies have tried (and so have I) to teach installers to make cars sound great, but there's just no way to make it possible for consumers to get the right experience predictably. I'd say that if you really want a useful evaluation of the value of any auto-tune, then the comparison shouldn't be between a car tuned by someone who knows how to do it and an auto-tune, but between an auto-tune and a car tuned by someone who has no clue.

In any case, I'm a damn good tuner and I can do a better job than MS-8 for ONE seat, but I have to have a hundred bands of parametric EQ, separate channels for every driver, time alignment and a fully adjustable logic-7 implementation, all pas filter capability, a microphone array a mic preamp with a multiplexer, A PC and two weeks. MS-8 does it in about 2 minutes. 

I can't do what MS-8 does for both seats simultaneously no matter what equipment I have in less than a month. 

Hmmm...maybe I don't know how to tune cars


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## Tendean17

thehatedguy : 
_Andy, you may have mentioned this to me before, but how important is timbre matching the rear speakers to the front? Do the rears have to be the same quality of speakers as the fronts? And finally do the rears need to be the same size as the fronts? 
_
Andy Wehmeyer :
The rear isn't critical, but it's really helpful to have something back there. The level that the rears will play with Logic7 will depend entirely on the amount of out-of-phase information in the recording. -180 degrees between left and right steers rear. It's great at steering room ambience in direct to 2-track recordings. Most pop recordings mixed using simple panning won't produce much rear information. Spacey sounding stuff, live recordings and anything you play back as a 2-channel downmix from a discreet multichannel recording may have lots of rear information. If you plan to do much of that, pay at least some attention to getting a decent pair of speakers back there and mount the tweeters at ear level.

The rear speakers should always have a high pass filter to keep them from playing anything below 100Hz. I usually use a 100Hz 4th order filter. So long as the rears can play between 100Hz and about 15kHz, MS-8 will correct the response well enough
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Technic :
_What the Logic7 in the MS-8 can do that the OEM Logic7 in BMW is not doing? 
_
Andy Wehmeyer :
Some of the steering settings are different but the fundamentals are the same. The MS-8's L7 is designed to provide a center image located in the center of the dashboard. Some of the OE systems are designed to provide a center image in front of each listener
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perfektj : 
_Was there ever a post of a detailed wiring diagram for the system in the BMW? I count a total of 14 speakers and 2 subs. I assume that the front three channels with the 4" and tweets are using one channel a each and the same for the two 8" midbass. Are the subs using one channel? Are the rear and side speakers on the same channel? I am trying to plan a similar set up for my Suburban, and need to figure out how the eight channels are allocated. Thanks 
_
Andy Wehmeyer :
Precisely. 4" and tweeters in the front left center and right use passive crossovers. The 8" under the seats use 2 channels. Sub uses one and the sides and rears are driven by the same 2 output channels also with passives between the 4" and the tweeters
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hallsc :
_Andy, In reference to a 3-way setup with rears, you concurred with western47 that the left and right front speakers must have a passive crossover between two of the three speakers each. Is the MS-8 capable of producing a mono (L-R) output? 
I have a vehicle that I am only interested in setting up for driver's seat; I don't carry passengers enough to care about how it sounds from other positions. My desire for final setup is three-way in the front, two speakers in the rear wired in series with an (L-R) output as described in the huge L-R thread, and a sub. If the MS-8 could output the (L-R) with the one channel, it would be possible for this whole setup to be active, which I would greatly prefer due to intened location of the front speakers causing TA to be a factor. Is this possible? 
If not, is the processing sent to the rear channels from the MS-8 much more advanced than the traditional (L-R) illusion? More importantly, if the above setup is not possible with the MS-8, under which setup would I get more out of my system (tuned for only the driver's seat) through the MS-8:
a). going 3-way partially active (2/3 speakers share passive crossoveron each side), a center channel (possibly), two rear speakers, and a sub, or
b). going 3-way fully active, center channel (again possibly), no rears, and a sub?
Thanks Andy for putting so much time and thought into keeping us well informed of this project!
_
Andy Wehmeyer :
My suggestion is to do a 2-way in the front and use two channels for the rears. Since you only need one seat optimized, this will work great without a center. Connect the mids and tweeters on one output (per side) of MS-8. The crossover between them can be outboard active or passive. When you do the acoustic calibration, (the first of the 4 sweeps), disconnect or cover the tweeters so the time alignment will be set of the location of the mids. The tweeter balance will be set by left and right level matching and EQ. 
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perfektj : 
_Andy, I have a set of convertible components that I am going to install in the front and rear doors of my 2005 Suburban, do you think that it would be better to leave them as a point source or to place the tweeter higher up in the A and B pillars? I am planning on fabricating a center channel by either making a speaker pod that sits on top of the dash or placing the midrange down low and the tweeter on the center of the dash. Do you think that it would be best in this application to go 7.1 and add speakers in the D pillars because of the size of the Suburban? Your help and input will be greatly appreciated. Thanks
_
Andy Wehmeyer :
Front tweeeters on the dash on separate MS-8 channels and combine side and rear on two channels. If you can put the whole center on the top of the dash, that'll be best. Use a passive network between them and use a single channel for the center. 

Or, put the front tweeters on the dash, use the passive that came with them, use 4 channels for sides and rears and one for center. If you choose this option, use the suggestion above for covering or disconnecting the front tweeters so the time alignment will be set for the front midrange location. 
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Andy Wehmeyer :
Where are the right and left speakers going to go? If you can get a 5" in the center and don't need the car to play super loud, the 8" and the center woofer are overkill. If your center can get close to 100Hz, it's fine and there's no need for more difficulty. There's also no need for a sub crossover at 50Hz, so this whole midbass thing is kinda overblown for MS-8 based systems. See your reposting of my post above and think carefully about the sub bass control. That's the key. Boosting the bass doesn't add a bunch of midbass contribution from the woofer.


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## Tendean17

fish : 
_Say I have 4 midbass drivers - one in each door - two midbasses in parallel to one channel. Will the MS-8 be able to do it's thing with time correction since the two drivers on the same channel are in different locations?
_
Andy Wehmeyer :
I assume you meant 2 in each door. Yes, MS-8 will work with this configuration. It'll time align accourding to the nearest speaker--it searches the impulse response for the initial peak--which will be fine.
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fish : 
_I had asked you the question about dual midbass in EACH door about a year ago, & you said it would work. 
This question is in regards to 4 midbass, 1 in each door of a sedan. 
I know this would probably be stretching it, just wanted to know for sure before I was past the point of no return.
_
Andy Wehmeyer :
Sure, it'll work. If you're going to use L7, I'd cross the rears over at about 100Hz 4th order, but even that's no big deal .. Oh, wait. If you mean a midbass in the front door and the back door connected to the same amp channel? I wouldn't do this.
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thehatedguy : 
_Andy, what about 2 seat with no center?
_
Andy Wehmeyer :
2-seat with no center works like any other system with time alignment. Great in one seat, not so great in the other, as far as imaging goes. The "Front" optimization will have frequency response balanced for both listeners but won't image. 
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thehatedguy : 
_Even with kick mounted mids that have a 6" PLD?
_
Andy Wehmeyer :
Yes, it'll be better in one seat than the other in "Driver" or "Passenger", but in "Front" there won't be any left/right delay. 
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Thaid and Bound : 
_From this can we also assume the rears should be able to play full-range?
_
Andy Wehmeyer :
Don't use the rears below 100Hz and above 10k isn't necessary.
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doitor : 
_Andy, I just bought an MS-8 from an authorized dealer in the US and should be here by Friday.
It will be the first one in Mexico. 
Got a question about the rear channels.
Would I get better results with the rears on the rear doors or if I put them in the D pillars?
I have a Mazda CX-7 with HAT Legatia L831-3 up front, JL 13 tw5 on the hatch and can put either L3's or L4's on the back. Thanks. Jorge.
_
Andy Wehmeyer :
Either would be OK. I prefer to have surrounds mounted at ear level, so I might be inclined to do the D pillars.
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Se7en : 
_Andy, is this based on general principal or specifically how the MS8 would respond to tweeters at different height locations in the car.
With my tweets in the kicks, stage height is very good with the MS8 managing things. Would having a center-dash mounted tweet mess things up? Thanks!
_
Andy Wehmeyer :
With the steering, we don't have to be worried about generating a phantom center, so we can use the tweeters to raise the stage and add width--that's what A-Pillars do. If you have good stage height already, mounting speakers in the top of the dash certainly won't screw things up.
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Andy Wehmeyer :
If yo have no center or rear speakers, turn L7 off. It won't do anything for you. If you have rears or a center, L7 is pretty helpful.


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## Tendean17

yuri : 
_i have post this question on erin's review tread ,but maybe i should of posted here ,,soorry. erin , andy or anyone know if its possible to run the ms-8 .
3way (6ch) up front ,mono sub(1ch) and use the 8th channel for a band passed mono rear fill ? maybe even you could use the on-board amp on the ms-8 to power the rear fill .. if possible it would be interesting to see if it added ambiance to the sound stage depth ?
_
Andy Wehmeyer :
Rear fil has to be stereo. That's how L7 works. If you don't have enough channels, combine the front tweeters adn midranges and use a passive. That works fine.
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Andy Wehmeyer :
Rear speakers don't need to make any bass, but they should include a tweeter. Coaxials are great for rears.
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jimbno1 : 
_You don't plan on a sub? If so you are a channel short. Same kind of boat I am in._

Andy Wehmeyer :
Use a passive crossover on the center channel. 
All 8 input chanels are summed, so no retaining of the factory fader control.
With L7 off, front and rear are the same. With L7 on, the rears and sides play ambient sounds contained in the recording (defined by the phase relationship between right and left channels) only. 
Sides and rears are assigned in pairs. There's no mono rear supported as one of L7's benefits over other matrices is that it can resolve left and right in the back. 
You can only define rear channels after you've defined sides. If you have 2 speakers in the back, they are sides. If you have four, you can enter the ones in the rear doors as sides and the ones in the rear deck as rear. Don't sweat the difference. There's very little performance advantage of 7.1 over 5.1. 
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Andy Wehmeyer :
Yes, MS-8 fixes the relative delay between channels on the input. It can't fix PLDs through passive crossovers, but PLD's for high frequencies can be adequately compensated using level (EQ and gain). Covering the tweeter during the first set of sweeps will cause MS-8 to locate and align for the mid and the tweeter can be fixed with the Auto EQ.
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Andy Wehmeyer :
The sub channels are mono and are treated together as one. The sub isn't stereo and those two channels aren't EQed differently. The two channels are simply there to make it easy to run two amps. Don't use the single under-seat woofer.
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AAAAAAA : 
_It's cool but I find the stage to be vague without the center channel.
Over all sound is better then anything I have had in the car but the stage isn't particularly good in my experience with just front and rear sides. (my comments reflect stock door mount locations, results should be better with better aiming\kickpods).
_
Andy Wehmeyer :
If you're running a 2-way in the front with passive crossovers, try covering the front tweeters during the first set of sweeps. That will cause MS-8 to tie align for the mids and should firm up your center image.
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hallsc : 
_Andy, Say we are going the route of 3-way front with rears, center, and sub, with a crossover between the mids and tweets. If we have the mid/tweet close to each other (less than 6 inches edge-to-edge), I am assuming covering/disconnecting the tweet is unnecessary?

_Andy Wehmeyer :
Right. This tweeter trick often helps with a 6" in the bottom of the doors and the tweeter in the sail panel.
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xr4tic : 
_I tried it both ways, but I liked it better with Logic7 turned off (2-way no center), I thought that was the consensus anyways.
_
Andy Wehmeyer :
If you don't have rears or a center, don't use L7. If you have rears and no center, try L7. If you have a center and no rears, add rears and use L7.
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Andy Wehmeyer :
The horizontal dispersion will be narrow but the vertical dispersion will be wide. Reflections from the dashboard will contrbute more to mucking up the response than lobing, but there's no way around that. Is it optimum? Probably not, but it'll be better than ANY alternative using those drivers. Using one will reduce the potential bass output, which is much more important than any of the other considerations. The tweeter is also important. 

Just stick the drivers in there, make sure the baffle is well sealed to prevent bass cancellation and let the EQ do the rest. There's only so much you can do with speaker placement, considering that the whole dashboard is the baffle. It's a car. Everything is a trade-off. Bandwidth from the center is the most important consideration. Second is placement in the dashboard. Of course, all of those take a back seat to cosmetic integration, in this case.


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## Tendean17

Niebur3 : 
_Anyone else? I have one person saying 3-way with mid in the pillars and 1 saying 3-way with mid in the kicks. I read what was written by Andy about Logic7 that was posted above and the way I read it, I should put my MB in the kicks instead of doors, or possibly not even do MB up front and just do Midrange? I am so confused at this point!
_
Andy Wehmeyer :
Don't make this more difficult than it has to be. The biggest center you can fit is best, but so is not having a big box on top of the dash or mounting the center channel in the back of the console. 

MS-8 is designed to send what can't be reproduced by the center channel to the front doors. Obviously, you want the center to do as much as possible, and the image for lower frequencies that the center can't reproduce will depend on time alignment--it'll be a little better in one seat than the other. 

Use what you have and use the 4 in the center. Be careful not to try to make the center play lower than it can. Start with a 200Hz crossover frequency on the center and 80 Hz between the doors and the sub. 80-200 that's steered to the center will instead be sent to the doors, so you won't lose anything. It'll be fine. Changing the doors won't have any effect on the center. 

Finally, speaker matching for center and doors isn't necessary. Frequency response matching is, but that's what the auto EQ does. 

What will SUCK is if you cross the center over at 80 Hz if it can't reproduce those frequencies, because the steering of the low frequency center information depends on the crossover point you choose, not on the acoustic response of the speaker.
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Andy Wehmeyer :
Sure, there are advantages of a three way, but they hav nothing to do with the performance of the center channel. They DO have something to do with dispersion and making up for the near-side off-axis response of the bigger driver. I use a three-way in my car and won't go back. 

The reason i suggested what I suggested is because I seem to recall reading that a stock appearance was a primary concern for the poster. 

I suggest hooking up what's in the car now. Tuning it, making an evaluation of the shortcomings and fixing those once they are known.
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BigRed :
if you don't have a center, don't use logic 7. the rears will sound too loud in this configuratin so you will have to adjust the fader. this has been my experience
the rears are worth it if you have a center and logic 7. 
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Andy Wehmeyer :
I suggest turning L7 off if you DON'T HAVE REAR SPEAKERS and using it IF YOU DO. The level setting algorithm is designed to match the levels of the front, center, rear and side speakers and to set the subwoofer level about 3dB louder than I like it. That means that when you turn off L7, you'll have to adjust the fader toward the front if you want front stage and a little sound from the rear without L7. 

For those of us IASCA peeps who are used to front with no rear, the rears will sound too loud without L7, but to a non-competitor who likes to have sound from everywhere (my dad), this will sound great. For those super-technical bonus-point-scooping competitors, adjusting the fader a few notches to the front ought to be a pretty simple adjustment, but it sounds better with L7, so why not just turn it on?
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OSN : 
_My understanding from Andy W's posts is that some of the signal is steered to the rear channel that would just be missing from the playback if no rear channels are used.
_
Andy Wehmeyer :
Correct. Just install a pair of rear speakers.
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Andy Wehmeyer :
MikeF, The calibration disc is ONLY for input setup. If you're not using a factory head unit, you don't need it. If you're having trouble getting a good center image, the sweeps are most likely too loud. If MS-8 is powering the speakers, start with the MS-8 volume at -20. If you have additional amps, start at -30. If you have a sub connected to an additional amp, turn the gain down. If you're worried that the sweeps aren't loud enough, then that's about the right level--especially the sub.

The first set of sweeps set the time alignment and the last three set the EQ. Time alignment mostly determines the center image position, but bad EQ can screw it up too. Try acoustic calibration again. Just do the driver's seat to start, until you find the right level for the MS-8 volume control. 
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Andy Wehmeyer :
Rears are really helpful. Center provides good imaging in all seats at the same time.
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Andy Wehmeyer :
Logic 7 steers the entire signal to the left, right and center speakers. Bass below the center channel's crossover frequency is sent to the right and left speakers and bass below the right and left speakers' crossover frequency is sent to the sub. You can use a small center speaker, but it's important to cross it over in a range where it still provides god output, because the bass management depends on the crossover frequency you select. 

Put the biggest speaker you can get in the dash for your center, but it MUST include a tweeter and a midrange. Installing ONLY a tweeter in the center is a mistake. Someone will chime in here and tell you that a "widebander" is a good idea. It's easier, but the "no tweeter necessary" pitch for wide-band midranges is marketing hooey. 
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Andy Wehmeyer :
Yes. there is no such thing as a fullrange 3" if off axis response is important. In a car, it's important because there ar so many reflecting surfaces. For near field listening in a room (say, while you're sitting in front of a PC), where on-axis sound dominates by a wide margin, then you can get away with not having a tweeter.
Someone will do their best to refute this, but they'll be wrong.
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Duper : 
_What volume are you doing the sweeps at? You might be running them too loud and clipping the mics in the headphones.
_
Andy Wehmeyer :
That's what this sounds like to me too. Choosing "Front" instead of "Driver" will essentially shut off time alignment for left and right, so you'll hear the speakers instead of an image. 

If you have a good center image with the unit in "Driver" then the first set of sweeps aren't too loud. And the midrange and high frequency sweeps probably aren't too loud for sweeps 2-4. I suspect the subwoofer sweep is too loud. Turn the sub amp way down and try again. Alternately, try configuring a system without a sub until you get the hang of tuning MS-8. Then, add the sub and make sure the sweeps are quiet--especially the sub.


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## Tendean17

*Aux Input, Signal Level and Preout Voltage 
*
Bikinpunk :
i leave my h/u volume at about 30 (keeps the internal fan from going crazy). I max out the ms8 volume. I don't need more than this.
Thing is, we're used to the system telling us when it's too loud. With a clean setup, you have to be smart about the volume because there's no issues with the FR from the system. A good home stereo is a perfect example. I have a friend who's setup you can listen to at full friggin' tilt and it doesn't break up. It's MUCH louder than you need to listen to on a daily basis, but the artifacts of speaker breakup/distortion aren't there to tell you this. 
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ItalynStylion : 
_Erin, have you tried using your headunit volume instead of the MS8 volume control? What effect does this have?
_
Bikinpunk :
I have. I haven’t noticed any ill effects, really. In fact, I ran some sweeps on it using my headunit volume control and the results were the same (linear).
Probably has a lot to do with how I set my system up, too. You can do it a lot of different ways depending on the volume you set your ms-8 to when doing the setup.
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JoeDirte : 
_Erin, couple of questions:
Do you feel like you lost any headroom as far as volume? I'm at close to max volume on both my head unit and the MS-8 and, with the volume fluctuations of mp3's, feel like I need a little bit more on some tracks. I've read in the MS-8 thread about ways around it, but was wondering if you experienced this as well.
2. Have you used your BT phone functionality since installing the MS-8? I called my wife once and she said the echo was so bad we had to end the call. My theory is that the time delay of the MS-8 was messing up the noise cancellation algorithm of the BT module. (I have an Alpine BTW) 
Thanks.
_
Bikinpunk :
Nope. In fact, I’ve gained more headroom. I think I mentioned it in one of my posts somewhere… probably the bit about noise in the 2nd post here. 
It’s all dependent on how you set things up. I found that setting the ms-8 volume at about 30 during the setup gives me plenty of headroom. 
2. Yea, my wife said the same. I’m thinking this is probably an effect of using L7 with no real center. As I’ve said, and as Curtis has said above, weird things happen when you run L7 without a center. 
Have you tried it with L7 off? If so, was it the same? I’m thinking it probably won’t be.

i leave my h/u volume at about 30 (keeps the internal fan from going crazy). I max out the ms8 volume. I don't need more than this.
Thing is, we're used to the system telling us when it's too loud. With a clean setup, you have to be smart about the volume because there's no issues with the FR from the system. A good home stereo is a perfect example. I have a friend who's setup you can listen to at full friggin' tilt and it doesn't break up. It's MUCH louder than you need to listen to on a daily basis, but the artifacts of speaker breakup/distortion aren't there to tell you this.
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less : 
_I'm very sad to learn that JBL continues to insist on making products for the masses when a little extra investment could have made their product useful at all skill/knowledge levels. I guess the assumption is that there are already products out there for people who need digital inputs though, and if that puts your product at a lower price point by avoiding the extra expense of dealing with digital inputs... well then your product may well serve its intended market.

Still a shame though =)
_
Andy Wehmeyer :
Less, I'm sorry that MS-8 won't meet your requirement for a digital input. We didn't remove that from the spec because of the cost of the input, we removed it because the inclusion of a digital input would have caused a bunch of confusion for many consumers who use that as a qualifier, but who are unable to understand its use. MS-8 runs at 48k. PCM is 44.1. Alglrithms that are designed to provide spatial processing don't freak out because the samples don't match, but digital EQ does. The real benefit of digital input is noise immunity and we've chosed to deal with that in other ways. 

Because the device doesn't include a feature YOU require doesn't mean that it's a low-end POS designed only for neophytes and the rest of the unknowing mainstream. It means that we've made a conscious decision to provide a device that does what it does and provides a high quality experience for those who wish to build a system for it. There are far too many "technology" devices that include every option and attempt to appeal to every use case and every consumer. Those devices often do many things poorly and notthing well at the expense of cost and complexity of setup. That sounds like a bad deal and one that I'm not signing up for. Building a device that does what it does well is the most important criterion for a succssful MS-8 and that's why it's taking so damn long to finish it. Sorry about that, but getting it right and providing clear instrucions for being successful in using it are the right decisions. 

The fact that MS-8 doesn't meet your criteria simply means that your use case falls outside of the use cases that we are determined to satisfy with a high quality experience. That doesn't make it a low end piece of gear or indicate that the brand made a decision to not to appeal to skilled users. Your criteria set the bar for your purchase decision, but not for all skilled users. 

I'm pretty knowledgeable and I'm eager to purchase an MS-8. 

The autotune in MS-8 is designed specifically to do cars, where there is no reverberant field and where all reflections are early reflections. In a car, there's no need to distinguish between speaker response and room response, because we hear it as one response. EZ-SetEQ, which is a feature of some of the higher-end HK receivers is based on the same basic process and uses a similar algorithm. but includes a near-field measurement designed to correct speaker response and an additional set of measurement designed to correct room modes. Unlike MS-8, it's already available.


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## Tendean17

Weightless : 
_Andy, Without having to re-read the entire thread, I have two questions:
1. Are there still going to be aux inputs?
2. Will there be the ability to eq the inputs?
_
Andy Wehmeyer :
Yes, there are Aux inputs. No, there's no EQ for the inputs. Why would you need EQ for the inputs? If it's to make up for supposedly bad frequency response of a media player, just EQ the output and save it as a favourite
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Andy Wehmeyer :
You should only choose "Skip input setup" to avoid the input processing if you're using the 2-channel full range outputs of an aftermarket head unit. If you're using a factory head, you should run input setup. As a general rule, if the front speakers include a midbass driver, that's enough of the signal for MS-8 to figure out what it needs to figure out. If the mids are little (BMW 3-series, for example), then hooking up the output of the factory subwoofer amp may be necessary.
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Andy Wehmeyer :
IF you're having trouble getting a good tune and the bass is what doesn't sound right to you, turn the sub amp gain DOWN.
If the mids are inaudible and the bas sis too loud, there are two possible problems. 1. Midrange speakers are conected out of phase, 2) all the sweeps are too loud. What volume setting are you using on MS-8 during acoustic calibration and is there an additional amp driving the mids and tweeters?
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Gary Mac :
_Well forum muscles, if you notice, my question was asked in this thread as a follow up for clairification of another member's statement.. Are you implying I should seek clairification of a person's statement in a thread different from where it originated? Anyway, regarding the loudness of the calibration tones for set up, I dont think 85db was the right number, here is why: I searched through the main ms8 thread, the only post that really references loudness of the tones was 3565, and the follow up posts never really mentioned an optimal db level. I think 85 is too loud because when I measured the loudness with MS8 volume at -30, the tones were at like 67db, now my gains were kind of low @ about 1/3, but even after I set my gains higher to about 1/2 and put the ms8 volume @ 20, the tone's level was about 77db or so. So Im thinking 85db would be too high because Andy consistently recommends set up to occur between -35 and -20 and uses the statement "if you think its too low (in terms of volume), its probably correct," 85db would be pretty loud and I dont think anyone would percieve that as being too low. 
The good news is, my midbass and low end of my mids was much improved with the increased gain and higher volume calebration over the lower-volume calebration, however the front image is less focused.
_
Andy Wehmeyer :
that's an iindication that the sweeps are too loud--time alignment isn't set roperly because of aclipped mic. I'm sorry guys, I haven't had tiime to determine the appropriate level of the sweeps. 
All of this midbass discussion suggests to me that the target curve may not include enough midbass for people who compete or who are used to competition cars. Just add some with the 31-band EQ. 
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Andy Wehmeyer :
Hmmm...there's no mystery to "Signal Level Low". That just means not enough voltage. A line driver will help, but putting the stock amp back in and tapping the speaker leads after it will accomplish the same thing. Since the factory amp is already out, a line driver may be easier. Are you planning to use the factory volume control or MS-8's? IF factory, make sure the output of the head isn't fixed-level.

The inputs of MS-8 are differential--speaker level and line level. the difference is voltage sensitivity. Do be sure you're using the RCA inputs if you've taken the signal before the amp (at least in this car).
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eviling :
_alright i have a 7200 mkii (being replaced later) and i'm adding an ms-8, but the ms-8 is going in first as the deck is twice as much anyways, my concerns are here. now i understand the ms-8 is a stock integration unit intended for integration into stock systems or mild after market units, but since my 7200 mkii has 8v preouts (at max of course) i understand i have to find where 2-4 volts are with the volume, and keep it their at all times? or can i just not go above that point once i set it? will the ms-8 adjust accordingly like that, or will i need to set it at the 2-4v range and keep it their always and use the control unit to adjust the volume? just some logistics im trying to figuire out before i get this unit i mean if i have to store the unti till i get the new deck so be it but i would like to install it right away 
_
Andy Wehmeyer :
The difference between 4V and 8V is 6dB. No big deal. You'll discover that you can turn the head unit control up farther with some music than with other music. This depends on crest factor and the amount of dynamic range compression in the recording. Just install the stuff and enjoy it and don't worry so much about all the specs.
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USC_GameCock :
_So what you're saying is you don't recommend allowing an input greater than 2V into the MS8? I mean, clipping is something that we try and avoid at all costs right? For example, if the head unit has 8V pre-outs, then set the head unit volume around 20 - 25%, then use the MS8 volume control, right?
_
Andy Wehmeyer :
If the head unit has 8V preouts, use the high-level inputs.


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## Tendean17

Swagger :
_I’ve read that you don’t necessarily need to use the MS-8 volume control if you’d rather opt for stock volume control. With the changes that have been made to the MS-8 since it was originally announced, has that changed? If it hasn’t, and the use of stock volume is still possible - will there be noticeable degradation in sound quality by leaving MS-8 volume fixed and controlling the level with the OEM head unit? 
_
Andy Wehmeyer :
No, you don't have to use MS-8's volume control. During setup, the display will help you determine what the maximum volume control setting on the head unit you should use to avoid clipping the inputs or sending a bunch of distortion through the processor. Many of the dynamic EQs included in cars are designed to overcome ambient conditions and those don't change when you install aftermarket gear--like road noise, etc. Bass cut provided by some Delco systems can be annoying because the EQ setting for high volume may be bass heavy at lower volumes. 

The short version of the answer is, "Sure, it'll sound fine if you use the OE volume control."

The long version is that in that car, it'll be fine and you probably won't hear the difference. There's no reduction in bass response provided by the OE DSP at high volumes, like there is in some other cars, especially GM. One other point that I'll explain in the interest of completeness but that won't be audible is that the inputs to MS-8 feed a/D convertors almost directly. They're designed to recieve some maximum voltage. Ideally, best resolution can be had when the signal peaks match that voltage. During setup, MS-8's display will ask you to turn the volume up until the level of the test signal meets that condition. If you want to use the MS-8 volume control, that's where the head unit's control should be kept. If you use the OE control, it's best not to turn the volume up higher to avoid clippping the A/D's input. Turning the volume down, just means that fewer bits are used to describe the audio signal. It's no big deal and I've been listening to and competing with a system thhat functions similarly. Deatil and resolution are definitely not the weak points in my system and any one who has heard it can attest. If you get hung up on the whole audiophile thing, then using the MS-8 control preserves the resolution of the analog to digital conversion, but the reality is that the convenience of using the OE control outweighs the need to satisfy some technical goal that can be measured but that doesn't degrade the experience. Fortunately, MS-8 includes both options.

We deserve all the ridicule you guys can dish out. It's no fun, but it's deserved.

Anyway, the EQ in MS-8 isn't a multi-tap filter (like the Audyssey), nor is it a standard parametric EQ or a graphic EQ (like Cleansweep). It's something far more bizarre. It works great, and with 8 biquads per channel can do more work than 512 taps. It doesn't EQ phase separately from frequency magnitude, but in my experience, that isn't necessary so long as you have a center channel and a matrix or some other center signal extraction method or time alignment. MS-8 has both. 

One thing that's important to remember when you're setting crossovers with conventional gear is that what appears to be a gap may, in fact, not be a gap. Here's an example (but without pictures, because I'm lazy today).

Let's say you cross your subs over at 100Hz and your mids over at 200Hz. Both slopes are 12dB/octave. When the output of the subs is precisely the same level as the output of the mids, the subs are down 3dB at 100Hz and the mids are down 3dB at 200 Hz. At 150Hz, both are down 6dB. Now, adjust the input sensitivity of the sub amp, so it sounds like you have bass. Let's say you boost it by 12dB. Now, the sub is up 12dB at maybe 80Hz and below, up 9dB at 100Hz and at 0dB at 200Hz. Now where's your crossover point?

200Hz. 

MS-8 avoids this problem by providing one crossover frequency setting for the sub and the midbass, adjusting the final slopes and frequency automatically using the acoustic EQ and then providing a bass shelf filter as a subwoofer level control which is applied to all the channels through the crossover. That way, the midbass and the subwoofer get the appropriateamount of boost at the right frequencies to add bass to the system while maintaining the proper crossover point so the bass doesn't become boomy and direectional. It works great and I have that process running as a VST plug-in in my car now. 

We're still working on the last two software modules, but there significant progress. We'll have some samples one of these days. Sorry for the delay and continue flaming us all you want.
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Andy Wehmeyer :
Gain potentiometers, clipping indicators and all things like that are specificaly EXCLUDED from the definition of the product. We don't want users to have to fuss with all of that. Here's how it works, described as simply as I can do it. 

If you have speaker level outputs from your radio or factory amp, you connect them to the speaker level input connector. Factory amplifiers (the vast majority of them) us the same kind of output amps, so MS-8's speaker level inputs are designed specifically to work with them with no additional adjustment. The line level inputs are also fixed and designed to work with most head units. Line drivers shouldn't be used--the idea is to make this easy. 

The setup CD is not pink noise. It's a specific collection of tones and it's different in the left and right channels. The UN-EQ is designed to look for CORRELATION between the incoming signal and what it's expecting to receive (it knows the signal it's looking for). Linear changes to that signal--like a different frequency, phase or delay allw that correlation and are things that can be fixed. Non linear distortion--like clipping--prevent that correlation. A a bunch of nasty noise will too. No signal will also fail to correlate. Clipping from the head unit will also cause it to fail to correlate. When you're adjusting the volume during setup, the display will tell you whether the signal is too high, too low, too far right or too far left. Once it gives you the OK, then you know the level at which there's clipping--whether that's from the head unit or the inputs of MS-8. You make a note of that level on the head unit and that becomes your new "max volume"--if you're playing a signal with all high bits. For quieter recordings, you can use more volume control. For the most precise playback possible, you'd set the head unit volume there and leave it. Then, you'd use the MS-8's remote control for volume. That isn't necessary, though. You can use the head units volume control all you want, provided you can live with the occasional clipping that may happen if you turn the control up too far.

The benefit here is that you don't have to adjuct a bunch of imprecise potentiometers and the unit can determine the point of clipping regardless of which component is clipping


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## Tendean17

t3sn4f2 :
_Andy, a question about higher voltage balanced sources.
If I have a soundcard that can either put out 2 volts RMS unbal or 7.7 volts RMS bal. signal and I want to use the balanced option in order to squeeze out the extra .8 from the MS-8 that I can't get by only sending it 2 volts unbal. Then where do I connect the balanced signal? The speaker level inputs?
If so, is there any degradation of the signal by that MS-8 using that input compared to RCA the line level inputs?
_
Andy Wehmeyer :
Yup. Use the speaker level inputs.
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TPMS : 
_Andy, back to technical questions, I have one more if you're still available..
just wondering if ms-8 will help with the low signal level I have now from pre-outs of the HK audiogateway. for example, at front it is something less than 0.5v and after dividing it to feed 2 different amps (one for mid lows and one for midr and tweets) I think it gets still lower and I have to turn the gain to max. further, also the sub signal is very low ..
so, I am hoping that after feeding only front signal to ms-8 he will manage things better and help with all these problems ..
_
Andy Wehmeyer :
Voltage in a parallel circuit is constant. What that means is that if the output of your head is .5V, then all the amps connected to it also get .5V. Of course, there's a practical limit to the amount of current the head unit will provide, so connecting a bunch of amplifiers might drag that down a bit if the current requirement became too high, but the input circuits of amplifiers are designed not to have that effect for practical systems. 

In any case, we've left a pretty wide wiindow for input voltage that will work and I think you should be OK. 
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CraigE : 
_What is the advice for HUs that exceed the MS-8 max. line input voltage of 2.8v ?
In my case the Kenwood DNX 9140 line output voltage is 5v.
With the volume control at 33/35 it is just under 5v, when checked with an O-scope.
_
AdamS :
Use 'Skip Input Setup' during calibration.
Keep the Kenwood under 2.8 V (~ 5 dB from the top).
Keep the MS8 Volume at -10 dB or less. This gives some headroom for the bass part of the target curve.
Control volume with either Kenwood or MS8.
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michaelsil1 : 
_Adam, Do you have a HU Volume recommendation for the Clarion DRZ9255?
_
AdamS :
A quick look at the spec:
http://www.clarion.com/us/en/MungoBl.../DRZ9255,0.pdf
says 8V Max.
This means you would need to be ~9 dB down from max.
With stepsize of .5 dB, that would be ~18 steps
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Andy Wehmeyer :
The head unit voltage thing is outta control.

Here's the deal--we always want to be able to clip the input of our equipment. If you can't, then good recordings that don't include a bunch of dynamic range compression won't sound loud. If you have an aftermarket radio, skip the input setup and calibrate the system. Put in your favorite CD. Turn MS-8's volume control down to about -20. Turn the head unit volume control up until you hear distortion that you find annoying. Turn it down until you're no longer annoyed. That's the max volume setting. 

If that's not good enough, then put the setup CD in the aftermarket unit and run input setup. Then the unit will tell you where the level is right. you can write that volume control position on your hand as though you were Sarah Palin so you'll remember it. You can then either finish the input setup, which will run the un-EQ/un-Time alignment routine or you can select "quit" and go back and choose "Skip input setup".

Center channels need tweeters--or they need to be able to reproduce 10kHz over a fairly wide dispersion.
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Se7en : 
_Andy, I have a question about the MS8 processing. I've had mine installed for a few hours now and feel like I've lost an enormous amount of system gain/headroom.
Using the line level outputs from my factory HU, the MS8 is telling me that the signal is too low until I've turned the volume up to 70% or so. 
I'm assuming that the EQ is is bringing everything way down, but am not sure what it would do in the case of a null. It seems like I have to turn the system up almost to the point of clipping to get it to a reasonable/loud level when driving at regular highway speeds.
Thanks for any insight you can offer.
On a side note, the staging is excellent, very focused, very high and centered. Tonality seems to be good as well.
_
Andy Wehmeyer :
There are a couple of things you can do. The first is turn your head unit's volume control up higher while you listen. Depending on the recording, there will be lots of crest factor or not so much. You can deterine the max volume setting with music by turning MS-8's volume down to -20 or so and turning up the head unit until you hear distortion that annoys you. Then, turn it down a bit. 
If you're usiing additional amplifiers, turn the input sensitivity controls down, re-run acoustic calibration and then turn the input sensitivity up on all the amps by the same amount. That ought to fix it.


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## Tendean17

Se7en : 
_Andy, I have a question about the MS8 processing. I've had mine installed for a few hours now and feel like I've lost an enormous amount of system gain/headroom.
Using the line level outputs from my factory HU, the MS8 is telling me that the signal is too low until I've turned the volume up to 70% or so. 
I'm assuming that the EQ is is bringing everything way down, but am not sure what it would do in the case of a null. It seems like I have to turn the system up almost to the point of clipping to get it to a reasonable/loud level when driving at regular highway speeds.
Thanks for any insight you can offer.
On a side note, the staging is excellent, very focused, very high and centered. Tonality seems to be good as well.
_
AdamS :
The input and output calibration are decoupled. When the input goes from LOW to OK, that's a few dB below the clipping point of the input. As Andy said, you can probably go a bit higher than this.
On the output, you can always crank up the gain on your amps before acoustic calibration, but then run calibration at master volume -48 dB (an example). This is like turning a 21 bit calibration -20 dB) into a 16 bit calibration. This will still work well. Then, when calibration is complete, crank the master volume back up.
There's more than on way to do this. I'm just trying to give you more options.
Somewhat related...
Another way to save some dB in the output stage... if you have a position selector in the car already, put it in Front or All instead of Driver. MS8 will have less level matching to do and thus save that headroom.
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rain27 : 
_Andy, Could the huge midbass peak be due to having large midbass drivers (8 to 10 inches)? Or is this due to having the gains turned up too high for the midbass drivers?
_
Andy Wehmeyer :
It'll be an acoustic condition--that could be because the drivers are big and efficient or because the gain is up on the midbass channels. In any case, too much midbass or midrange will definitely be fixed by MS-8, but a huge and broad peak at about 600Hz is pretty common and makes the car sound really loud. Once that's fixed, it won't sound so loud. If you like a really thick midbassy sound, use the 31-band EQ to put it back.
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Andy Wehmeyer :
xr4ti, What did you use to measure the output voltage? I'm curious because I can't find any documentation that the radio in that car was ever intended to drive speakers without an amplifier. If that's the case, then the output voltage ought to be sufficient if it really is 5V, but if the outputs were never intended to drive speakers, the radio may not be built to deliver much current. Connecting it to a pair of speakers (which would be a load it was never intended to drive) would ask it to deliver more current than ever intended and that lact of current would cause distortion. 

What percentage of the volume control is "22"? Is that most of the way up?

Connecting the 5V output to the RCA level input will work fine, but before you do that, I'd like to better understand how you've determined the output voltage. If it's 10V peak to peak, then it's 5V peak and about 3.5V RMS. MS-8's inputs will take 2.8 V RMS before clipping, so there should be no issue connecting to the RCA inputs and even Adam's suggetsion about resolution won't really come into play unless you like to listen to sine waves recorded at 0dB with the volume of your head unit all the way up . I guess that's my way of saying that you should just hook up to the RCAs and it'll sound great.
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cubdenno : 
_Could you run a 3 way up front using mid/tweet with a passive crossover? If they were next to each other say on the dash? T/A differences would be minimal and with what the MS8 does, I would think it could compensate.
That way you could have your cake (3 way up front) and eat it too (rear fill/surround).
maybe it's been covered... or as asked above, run it all active just have the external crossover instead of the passive.
_
Quality_Sound :
Like Jorge above, it's what I'll be doing as well. 
T/A between the mids and tweeters is pretty much a non-issue since T/A doesn't work at frequencies that high anyway. You just disconnect the tweeters when you run the T/A sweeps and then reconnect for the FR shaping and you're good to go.
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bikinpunk : 
_I don't think you'd want to do this.
I'm pretty sure the algorithm the ms-8 uses is much more complex than a simple t/a calc.
Leave the two connected via passive. Let the ms8 do it's thing. 
The one thing I would worry about, however, is level matching. I wonder if the ms-8 has a shelving filter function that allows for level matching via passives. I'm sure it does. Otherwise, I don't see how it would be able to give adequate results to those running passives.
_
Hallsc :
iirc, I think that's excatly what Andy told me to do in a post maybe 30 pages back when I asked him this same question. With a 3-way using passive crossover between mids and tweets, unplug the tweets during the time alignment part of the tuning. Then plug back in for rest. Andy is welcome to correct me, but that was what I took from his solution to the 3-way plus rears plus sub plus center (optional) problem. For level matching, the passive crossover should level it enough to allow the EQ to take care of the rest, I would think, provided the crossover would have a +/- 2dB or whatever setting for the tweets. Maybe even without.
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BigRed : 
_running passives works fine. my experience is based on the mid/tweet being fairly close to one another.
_
AdamS :
Yes. If they're close together, you can use passives. If they're far apart, MS8 will choose the higher frequency driver and this might cause an issue. If using an external digital crossover, turn off the higher frequency driver during the first set of sweeps at each position. Then turn it back on for sweeps 2,3,4. This will localize to the mid instead of the tweet.


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## Tendean17

xr4tic : 
_I'm still having the same issue, no bass.
I've got my sub amp gain cranked to full, but when playing music the mid/bottom end is real faint, and it just sounds like crap.
If I turn processing off, it's all there, but of course the phantom center is gone.
_
Andy Wehmeyer :
MS-8 is designed to provide bass that's 9dB above the rest of your response. If you like a lot of bass, that's probably not going to be enough for you. When you do acoustic calibration, turn the sub bass amp DOWN. Then, MS-8 will boost the bass a bit. Then, after you've finished, turn the gain on your sub amp up. During the sweeps, if the sub sweep rattles the trunk, it's too loud. If you can feel the sub during the sweeps, it's too loud. 

There is one other possibility, especially if you have a little sealed box and you're using a really low crossover point--if that's the case, MS-8 is trying to get rid of the HUGE peak in your response.
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Andy Wehmeyer :
Between 85 and 90 dB is good. 

You should unplug the mic when you're done, just like you shouldn't play football in a busy street. Can you play football in the street when there's no traffic? Probably, if I was your father, would I tell you it's OK? Probably not. Can you drive your car as fast as it can go all the time? Sure. When you run into a flagpole or a streetlight, will the warranty pay for the damage? Probably not. My point here is that listening to MS-8 with the microphone plugged in is an unintended use and I can't guarantee great performance if you leave it plugged in. If the sweeps are at an appropriate level, the tuning will be remarkably consistent, so calibrating and recalibrating all the time shouldn't be necessary. That's why we provide a 31-band EQ. Time alignment doesn't change, speaker placement, the shape of the car's interior doesn't change and unless you're installing new speakers, they don't change either. If you want to calibrate every time you listen, then install something that will allow you to disconnect the mic easily.

This is a DIY forum, right?
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AdamS :
FYI - The level is based on the loudest speaker in the 300 Hz to 3KHz range. If the loudest driver is completely in that range, then the level is based on that driver. Otherwise, if your crossover is in between these two numbers, your reference level could be based on 2 or more drivers.
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Andy Wehmeyer :
If you're connecting to a factory system that includes a subwoofer and you're connecting the subwoofer output to the input of MS-8, the sub output of the factory system should be connected to MS-8's input 7 or 8. In order for MS-8 to sort out the right and left and mono channels and to remove the factory time alignment, it has to see a high-frequency channel before a low-frequency mono channel as it samples the incoming signals. 

The outputs of MS-8 can be connected in any order or configuration that's supported. That means there have to be right and left front at a minumum and that rears and sides are stereo. Front can be maximum of 3-way...etc...that's all in the manual.
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Andy Wehmeyer :
For those of you who are having trouble integrating the bass with the midbass, here are some tips:

1. The Subwoofer level control in MS-8 isn't a gain control for the sub output. It's basically a target curve adjuster and boosts or cuts bass with a filter that mimics the low-frequency end of the target curve. The target curve includes 9dB of boost below 60Hz with a smooth transition to 160 Hz. The subwoofer level control is a shelf that boosts or cuts below 60 and never above 160 (the slope of the filter changes with the amount of boost or cut. Use it to adjust the level of the bass before going after it with the 31-band EQ.

2. If you're using a factory head unit and your factory system has a subwoofer, disconnect the subwoofer output of the factory amp from MS-8's input and re-run input setup. This will work great if your factory midrange speakers are 6", but not in BMWs with 4" midrange drivers. MS-8 includes enough boost to put the bass back in so long as the factory crossover is near about 80Hz. The reason that this is important is that in many cars with factory subwoofers, the front speakers and the sub crossover aren't well aligned and the electrical combination of the two create a huge dip in the response that MS-8 tries to fix with boost. MS-8 can't determine if the dip is caused by a big "underlap" or because the two signals are out of phase at the crossover (because of alignment of the crossover frequencies and slopes). 

3. Reverse the polarity of the subwoofer and re-run acoustic calibration. 

4. If any of the first three don't do the job and you're using a little sealed box and your sub amplifier also has a crossover, set the amp's crossover to about 60 or 70Hz. This will change the overall response of the sub by reducing the boomy midbass it makes (which is picked up by MS-8's mic and used to set the sub bass level). Then, run acoustic calibration again. 

And, if you're having trouble getting a center image, the sweeps are too loud or one midrange/midbass is wired in reverse polarity. Verify the polarity by plugging a source directly into the amp that drives those speakers and playing a mono signal or use a 1.5V battery and check to see that the speaker moves forward when the battery + is applied to the speaker +. Simply checking the wires may not be sufficient, especially if you're bridging a 4-channel amp to drive the two speakers. If you used the B.S. "put one midbass out of phase to fix the image" trick for two-channel systems, you have to eliminate this for MS-8-based systems. It's a B.S. fix, anyway.
______________________________________________________________

jrsmiles : 
_During initial setup, the MS-8 is asking for a pretty highly cranked level out of my stock HU. I max out at 40, and the MS-8 gets an OK level at 35. 
Following the rule of thumb where you should top out at 75% of your HU volume, this puts me at about 87.5%. Is that normal?
_
Andy Wehmeyer :
Sounds about right to me. 

Start by setting the gains on the amps to the 2V setting. When you do acoustic calibration, start with MS-8's volume at -40. Don't do the volt meter thing

If you're getting the OK OK OK at 80-or-so-percent of the volume control, then you're fine. If you put something else in there to boost the voltage or do something else that makes MS-8's input max out at a lower setting of the factory volume control, the car will play louder with less "volume control" but nothing else will be gained. Nothing. I swear.


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## Tendean17

jrsmiles : 
_Maybe I've been reading too much, but I've confused myself. I've set my gains to about 25%, HU volume at 35/40. MS-8 volume at -40. Now I've run the acoustic calibration, and the listening volume is too low. I want maximum clean gain for each set of speakers, and a high sound level from the system. 
How do I increase my gains now to get the output voltage I'm looking for? I'm planning on using a multimeter per JL's instructions on how to verify gains, but I need to know I'm hitting the inputs on the amps with the high end of the limits in order to get an accurate gain output reading. What should the MS-8 level hitting my amp input be? -40? -20?
Thanks for the help, I've read through most of this thread and haven't seen any detail about verifying amp gain with accuracy, just some quotes about "turn it up from there". I'm sure there is a fairly simple answer.
_
Andy Wehmeyer :
Too much has been made over the years about gain and level setting. Some years ago, systems were made up of a head unit, an EQ, separate electronic crossovers and then amps. Setting levels in these kinds of systems was important, but we no longer use so many analog components in a lengthy signal chain. In a system like that, each component should be driven with the highest level possible before the outputs OR the inputs are clipped. and the signal sent over the wire should be maximized to maximize the signal to noise ratio. The reason for all of this was noise. Too much INPUT sensitivity and too little output voltage would result in system hiss and would boost the level of engine noise, which would be amplified by every component in the chain. 

We no longer have to be so concerned with all of that because systems now are often a head unit, a signal processor of some kind and some amplifiers. Additionally, components now often have differential inputs, which are designed to eliminate the possibility of engine noise.

So, with MS-8, the analog signal from the source is converted into a digital signal in the unit before anything else happens and we've designed the unit to make setting this level as easy as it can be. The RCAs are fixed input sensitivity and are designed to work with all aftermarket head units without any user intervention. Just plug them in and go. The unit, without EQ, is designed to provide unity gain up to 2.8V, which is plenty. That means if you put 1V in, you get 1V out. If you put 2V in, you get 2V out. If you put 9V in, you'll get 2.8V out but it'll be seriously distorted. When you turn the output of your radio down so that you send 2.8V, you'll get 2.8V that isn't clipped. 

Now, one of the reasons that all of this input sensitivity setting procedure was developed and that many of us suggest things like 10dB of gain "overlap" is because a system that can't clip doesn't sound very loud, especially with recordings that have a high crest factor and little dynamic range compression added to the final mixdown. You want your system to clip, but you want to balance that with the amount of noise (hiss) you allow the system to produce. You don't want much of this clipping to be digital distortion, because that sounds bad. 

If you're using a 4V head unit with MS-8, that provides 3dB of gain overlap. You won't hear much distortion unless you listen to sine waves recorded at 0dB with the volume control turned all the way up. With normal music and the head unit's volume control all the way up, only the transients that are recorded at 0dB will be distorted, but only by 3dB. You won't hear that and if you do, simply backing the volume control of the head unit off by a couple of notches will take care of it. 

Since the MS-8 is designed to provide unity gain, it's sufficient to set the input sensitivity of the amplifiers to the same setting as the output of your head unit for 0dB of gain overlap between MS-8 and your amps). This will ensure no input clipping of your amplifiers and will ensure the least noise possible. Double the input sensitivity will result in an additional 6dB of gain. So, if your head unit is a 4V unit, you can set the input sensitivity of the amps to about 1V, which will give you a total of about 9dB of "overlap". Precision isn't required.

Because MS-8 also has a volume control, you'll have to manage how you use it. You don't have to use the MS-8 control if you'd prefer to use the one on your radio. If you choose to do this, then you'll need to set the MS-8 volume control at some level that allows the right amount of "input sensitivity" but also allows enough digital headroom for the EQ inside of the MS-8 to operate without running out of bits (that causes digital distortion). I suggest setting the MS-8 control at -6dB to -9dB during listening, unless you boost the bass in MS-8. If you boost, then you should set it lower by about the same amount as you boost and then use your head unit's volume control. 

If this in't enough "gain" for you, then turn the amplifiers up after calibration by the same amount to maintain MS-8's "tune". 

You can determine the point at which your radio outputs about 2.8V by putting the setup disc in your aftermarket radio and running input setup. The point at which you get OK OK OK is the point at which your radio outputs about 2.8V. You can continue to run input setup and MS-8 will Un-EQ and remove any channel delay. If you're using an aftermarlet radio, none of that should be necessary so all of the EQ filters will be set to unity. That means what comes in goes out. If you choose "skip input setup", all of the filters will be set to unity. 

When you run acoustic calibration, MS-8 will set all of the output levels according to the acoustic response in the car. This takes into account the sensitivity of the drivers and their frequency responses. Some outputs will be increased in level and some may be decreased. So long as there's no hiss, the output level and the input sensitivity control of your amps don't matter. Let MS-8 do what it does. 

When you run acoustic calibration, the output of the system can't clip the mic, or things will be ugly. If the mic is clipped during the first set of sweeps, the unit won't be able to locate the initial peak in the response and it won't set time alignment correctly. You'll know this is the case, because there won't be a center image. This is all the volume control setting for acoustic calibration is doing--making sure the system doesn't clip the mics. To ensure this, turn MS-8's volume control DOWN. If you use MS-8's internal amps, -20dB is the highest setting you'll need. If you're using additional amps, you'll have to turn it down MORE. -40, maybe. This setting doesn't matter too much in terms of the final outcome, but the level does change the way MS-8 will boost and cut, because everything has to fit in a "window". The window is big, though.

This is no different than tuning with a regular EQ. If you boost all the bands to fix holes, you'll have a super loud car and you'll probably have lots of clipping and noise. You'll also probably boost in the interest of filling holes cause by acoustic cancellation, which may overdrive your speakers and cause additional distortion. MS-8 tries NOT to do this, but it can't know for sure. If your response has big holes because you're using an 8" midbass and a 1" tweeter and the wrong crossover point, you may hear distortion because MS-8 is boosting as much as it can to fill a hole that can't be filled. Fix the speaker system. MS-8 can't make gold out of crap. 

If, when you're tuning with a manual EQ, you cut all the bands to remove peaks, then you'll reduce the output voltage of the EQ at frequencies where you've cut and you'll probably want to readjust the input sensitivity of all of the amps to increase the level of the whole system to make up for it. If you think about it, this is how we all tune systems anyway. So long as you don't introduce a bunch of system hiss, this is fine. Cutting a lot and boosting a little is the best method. This is how MS-8's algorithm is designed to work. It works well, but GIGO still applies. 

Once acoustic calibration is complete, if you want to use your head unit's volume control, set MS-8's volume control to -6 and go crazy. If you boost a bunch with MS-8's EQ or sub level control, you may have to turn MS-8's volume control down to leave more digital headroom for the boost. This isn't a defect. This is how digital EQ works. Some digital EQs normalize the response. That would result in everything else being reduced in level as you boost the bass (or the EQ). We didn't do this because it adds complexity to the system and the result of boosting with these systems when you reach the level at which there are no more bits available is counterintuitive. 

If you want to use MS-8's control, do this: Put in a music disc, turn MS-8's volume control DOWN to something like -40 or -50 (so you know you're not clipping the outputs of MS-8 or your amps) and turn up the head unit's volume control. When you hear distortion, you'll know you're either clipping the output of the radio or the inputs of MS-8. Turn the head unit's volume control down until you don't hear any more distortion. This is the maximum usable output of the head unit for MUSIC and for that particular disc. If you listen to another disc with more or less dynamic range compression in the recording, you may find a different volume control setting produces audible distortion. This is related to our ability to hear distortion on transients, the length of the transients and how often those transients are repeated. The idea here is that you have control over the amount of clipping you allow. It is what it is and balancing the two volume controls will help you get the most from your system. I think the vast majority of systems will be fine. 

The bass can't clip the mics during sweeps 2-4 either, because the EQ doesn't know what to do. Be sure that the level of the bass is LOW during the sweeps. If you have twelve 15" woofers and you want to wake the neighbors, turn the amp gain WAY down during calibration. The bass should be heard during the sweeps, but you shouldn't feel it. Then, after calibration, turn the gain of the amp up until you're happy. You can't wake the neighbors and have 40dB more bass than mids and highs and maintain the illusion that the bass is in the front of the car, which is what MS-8 is designed to do. You'll have to adjust the gain of the amp to get what you want, because MS-8 tries to eliminate what you want. Let MS-8 do what it does, and then make your adjustment afterward. 

Finally, if the system doesn't play loudly enough, adjust the amplifier input sensitivity control to increase the overall system level. There's no need to use a meter or a scope. Just adjust them all up or down by the same amount to maintain MS-8's EQ and relative level settings. The VMM method won't work because there's a bunch of EQ applied to the signal, which increases and decreases the output voltage at different frequencies. BTW, the VMM method is only slightly more accurate than just setting by ear.

Don't be confused by all of the "this has to be precisely set to get the most from your system" garbage. If there's no noise (or the noise is low enough that you're not annoyed by it) and your system plays loudly enough, then things are set appropriately.


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## Tendean17

Ibanzil :
The ms-8 has an input setup you run. Put the setup disk in your cd player, play it and watch the ms-8 screen to say input over, turn down youre cd player until the ms-8 says the input level is good. Any headunit will work but you have to know where the input level is too high from the setup process.
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eviling : 
_well people want sound processing with out low level inputs from stock decks too :| i knew it had been speced at liek 2 volt in, and i havnt checked out the thread since before release and wasn't about to read 2000 posts lol, but anyhow, sombody said something about the software being able to figuire out where the voltage is on your deck at what levels and just not to exceed that and to use the MS8 head unit to ajust the volume?
_
Andy Wehmeyer :
Who has an 8V deck? Before you chime in, please check to be sure that the deck has a DC/DC power supply in it somewhere, 'cause that's the only way you're gonna get that. Unless it's 8V peak to peak that they're calling 8V. In that case, it's 2.8V RMS and that will work fine with MS-8.
______________________________________________________________

Andy Wehmeyer :
Guys, If you're using an aftermarket radio, there's no need to use the additional 6 RCA inputs on the unit. If you're using a factory radio, then you should use the speaker level inputs and connect to as many chanels of the factory system as is required to provide the MS-8 the entire front right and left signal plus the output for the sub, if there is a sub. We left the additional 6 RCA inputs intact in case there are cases where the output of the factory system doesn't provide enough voltage to register during setup or in case there's a need to sum speaker level and RCA level.

The owner's manual and the quick start guide are written as instruction for installing the system and making it work. They aren't intended to explain WHY everything works. If we had written that, it would be hundreds of pages long and itseems that even a relatively concise quick start guide is too much to read and follow.

Get this, we had a local (soCal) dealer install one for a reviewer. Took the veteran installer 16 hours to install it incorrectly for which the dealer charged us $1700. Finally, Gary Biggs had to fly out here while I was overseas to check it out and ultimately, turn the volume down during calibration.
______________________________________________________________

Andy Wehmeyer :
Wow...I can't believe all the focus on the digital signal thing. I think my car converts digital to analog 3 or 4 times before it reaches the speakers. I can't imagine being able to hear much of a difference. I supose if EVERYTHIG else was perfect or close, it might be the icing on the cake, but I doubt it. 

I'm also not sure that there's much of a comparison to be made between the Pioneer Head unit and an MS-8. Both have a room correction function. I know how the MS-8 works, but I can only surmise that the Pioneer uses some form of FIR filter. None of that matters. All that matters is that the target curve is right and that the algorithm comes close to hitting the target. 

No matter how good a tuner you are, you can't do what MS-8 does with a 31-band graphic EQ. Even if you don't like MS-8's target curve, tailoring it to your taste with the 31-band EQ after the autotune is still way more powerful and far more likely to actually fix problems than an RTA and a 31-bander by itself. 

I'm certain that the time alignment algorithm in the Pioneer is nearly identical to MS-8's. There's really only one way to do it--by measuring impulses and picking peaks. So long as the device can reliably pick the first peak, it will work. Sorting the near side reflection from the original impulse can be difficult because there's often more high frequency content in the reflection than in the original impulse. We have our own secret sauce and a pair of mics to do this. I don't know what the Pioneer does.

Oh, and line drivers are possibly the biggest waste of money ever invented--well, now that head units have more than 100mV outputs and amps have differential inputs. If you want to know where the real signal degradation happens, use a tool that will help you see it. Look at the waveform of a .wav file. then convert it into MP3 at 256k and compare. Hmmm...damn close. then convert it into analog and back into digital. Hmmm...pretty damn close. Then, send it to an amplifier and look at it again. Hmmm...nearly identical to the input signal. Then, measure it at the end of a speaker wire. Same thing. Then, put your mic in the driver's seat and measure the response at the listening position. Hmmm...looks nothing like the original. 

For my money, fixing THAT is far more important than worrying about the D/A and A/D.


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## Tendean17

*Measurement and Setup
*
Bikinpunk :
2-Seat and Passenger Experience :
When you switch the seating position over the the passenger's seat the effect is the same as if you were sitting in the driver's seat: excellent imaging, staging, tonality, etc, etc... basically nothing changes from the viewpoint of the listener. When you switch the seating position to 'front', it gives the best overall sound to both seats. This means staging and imaging drop off, but the overall system sound is still very nice, as one would expect. I couldn't imagine how long it would take to get these extra two benefits if you had to do it all manually. 
______________________________________________________________

Bikinpunk :
Yea, once you set your crossovers you are taken to a screen that allows you to test driver output. You can turn them on/off as many times as you like. At this point, it's a great time to check the output of your drivers and see how well they match, then fix the ones that don't match up so well. 
As Chadillac found here, if you don't get this right, you can cause all sorts of problems and chase your tail. 
After that, you're done. Just fire up the auto calibration and you should be set. 
______________________________________________________________

Bikinpunk :
A friend and forum member came by last night to test it out. We set it up for him. After he left I noticed that something sounded different but can't say for sure what it was. I re-tuned it anyway. As I said in our previous conversation, the results change depending on the user and how he/she goes through the setup (ie: angle they turn their head). I noticed a difference just by turning my head to 90* each side rather than the ~30-50* it takes to view either side mirror.
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Bikinpunk :
I notice the biggest difference when I turn my head further than the mirror location by about 20+ degrees. I'm not certain my head has been in the exact same spot everytime I've re-cal'd to see if the results are the same; I'm sure it varies by a small bit.

Now, if you're talking about another person getting in and cal'ing, then yes, there's a change. Especially if that person is of a different physical size. But, for my own testing, anytime I've tried to repeat the results it's been the same to me.

^ it's about equal stage width, to me.

flat out no way to get equal width from left/right and a center image in front you in the car when you're physically sitting left or right of center unless you do an asymmetric install. the nearest side will always be the weakest link. so, if you center is in front of you, in most cases you can bet that you're either going to have unequal width or you're going to have a squished (narrow) sound stage. I've never heard a car that had a center image in front while still retaining a wide stage. it's just a trade off.
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Andy Wehmeyer :
When you choose "driver" the correction filter determined using only the driver's seat measurements is loaded. When you choose "front" the correction filter is based on an optimization using measurements in the driver's and passenger's seats. When you choose "passenger" only the passenger's seat measurements are used to determine the correction filter. So the multi-seat measurement only matters if you choose an optimization that takes into account more than one seat
______________________________________________________________

Diffeomorphism :
_Okay, I follow that and I understand that the MS-8 is unable to store auto correction filter settings for "driver" and "front" and does not allow switching between the two. But is the benefit of having that apparent?_

Andy Wehmeyer :
No, that's not correct. If you measure all the seats, all correction filters for all available optimizations are stored. If you measure only one seat, then only one set of correction filters is stored. You're asking for the unit to store measurements so you can choose to measure all seats or one seat and switch between the two. I'm saying that you can have the result of what you're trying to do by simply measuring all the seats. 
Think of it this way. I could give you directions for getting from your house to the grocery store on one sheet of paper and then I could give you directions for getting from your house to Home Depot, which is 5 blocks further on another piece of paper. However, we only have one piece of paper, so I've given you directions for getting all the way to Home Depot and indicated where the grocery store is along the same route. Now, you only have to remember to take one piece of paper with you when you go and it includes directions for both destinations. 

Get it?


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## Tendean17

Diffeomorphism :
_I understand what you're saying, but I still feel there's a disconnect here. 
My question was; Will it sound different for the driver if only calibration is done in the drivers position versus the sound for the driver if calibration is done for multiple positions?
From what you said earlier, it will not sound different for the driver. I don't understand how this can be when taking into account more measurements for other positions. Thus a kind of 'average' of the two.
For example (conceptually):
Calibration from driver seat applies delay on the front left speaker because it is closer.
Calibration for 'front' (both driver and passenger) takes into account the above and the delay needed because the front right speaker is closer to the passenger. 
Wouldn't the 'front' calibration shift the soundsage/imaging from what it was for the single driver seat calibration?
_
Andy Wehmeyer :
No, I'm certain I've understood the question. Measurements taken in the passenger's seat do not affect the driver's seat calibration because they aren't used for determining that correction filter. All measurements aren't averaged for all seating positions. 
Let's try again:
When you measure the driver's seat, those measurements are stored during setup. When you measure the passenger's seat, those measurements are stored during setup. When you measure the rear seats, those measurements are stored during setup. When you press "done", MS-8 calculates separate correction filters for each of the seating positions using only the measurements that pertain to that seat or combination of seats.
For the driver's seat optimization, it uses only the driver's seat measurements. For the passenger's seat, it uses only the passenger's seat measurements. For the "front" optimization, it uses the measurements taken in the driver's and passenger's seats--and so on and so forth. For "all" it uses all measurements. Obviously, the more seats that have to be averaged the less "opitimal" the sound will be in any one seat when the optimization for more than one seat is chosen. "Front" won't be quite as good for the driver as "Driver", but it will be the best it can be for both front seat passengers simultaneously. 
You have exactly the benefit you're after, we just provide it in a way that's different than you expect
______________________________________________________________

Diffeomorphism : 
_Right, which is why I would like the ability to switch between optimizations; amazing for when only I am in the car and pretty damn good for when I have passengers. 
I really appreciate your persistence and willingness to answer questions regarding the MS-8. I wish I could interface a little more with companies like this. I feel like I've kind of hijacked the thread; sorry about that. 
_
Andy Wehmeyer :
Right. As I've written before, the "driver" optimization is NOT compromised by the other measurements because they are not used in computing the correction filter for "Driver". Storing that correction filter by itself or storing it on the same shelf with some other correction filters doesn't change the correction filter. 
I give up on this one. The unit provides exactly what you want, just not in the way you want it provided.
______________________________________________________________

RangOH : 
_auto eq. on top of the calibration. to tune for your individual hearing tastes. it could give you a series of different sound shapes that you choose from. and you choose the one(s) that sounds best. like the way a eye doctor finds your lens prescription.
_
Andy Wehmeyer :
Just draw the curve you want using the 31 band EQ. That's precisely what it's for
______________________________________________________________

Bikinpunk :
You eq/tone controls settings never change. And, you have 5 settings you can save.
you can save your settings but it's only for one tune. it's actually quite simple, however, to get the original settings back since all you have to remember is crossover points.
the autotune is very consistent. I've not had it give me different results unless I changed something (head angle, or amp gain). I've tested this function quite a bit.


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## Tendean17

Andy Wehmeyer :
The curve drawing comes after the Auto EQ. You can make changes to the sound AFTER the machine does its work. Setup goes like this:

1. Input Setup: Calibrate the input signal by inserting the setup disc and adjusting the volume until you get the level and balance "OK" indication. Then you press OK and it runs the auto Un-EQ. That whole procedure takes less than a minute.
2. Output Setup: You tell the machine via a menu what system you have. 

a. Whether you have a sub and whether it uses 1 or 2 of MS-8's outputs and then you choose a subsonic filter frequency and slope and then a low pass filter frequency and slope. 
b. Whether your front system is a 1-way, 2-way or 3-way. The high pass filter frequency is chosen when you choose the sub low pass filter. Then yo choose crossover filter frequencies and slopes for the midbass to midrange and midrange to tweeter (if you have a 3-way). If you only have a 2-way, then you choose the crossover frequency and slope between the mid and tweeter.
c. Whether you have a center channel and whether it's a 1-way or 2-way. Then you chosse the center high-pass filter frequency and slope and the crossover filter frequency and slope between the center mid and tweeter (if yo have a 2-way center).
d. Whether you have surround speakers and whether they are 1-way or 2-way. THen you choose the HPF and slope and the crossover between mid and tweeter (if you have a 2-way).
e. Whether you have side surround speakers. Then you choose the HPF.

MS-8 counts the number of channels you use and eliminates choices you can't make because you've rin out of channels. You MUST have at least a front stereo system. Then you can add speakers to make up whatever system you have.

f. Then you tell MS-8 which output channel is connected to the various speakers you identified in the previous steps. This whole procedure is pretty quick too, especially if you have any clue about what you're doing. You CANNOT input overlap or underlap between the sub and the midbass/midrange, midbass and midrange, and midrange and tweeters. Before you freak out and decide that the whole unit sucks because you can't input ridiculous crossovers, know that all of the crossover slopes and frequencies are adjusted when the Auto EQ runs. It works. Plus, the usual need for underlap of sub and midbass crossovers is handled another way--which works much better, anyway.

Once you've set up the outputs, an output diagnostic runs and you can output pink noise to each of the outputs (FR, FL, C, RS, LS, RR, LR and S) to be sure you've set things up correctly.

3. Acoustic calibration: You put the microphone on and press "Go". The unit makes 4 sets of sweeps in each seat (you must do one seat, but you can do all 4 if you wish) and prompts you to turn your head between the second and third and between the third and fourth to get a spatial average. The first set of sweeps sets the channel delays and the second through fourth are for frequency response.

4. Press "done" and enjoy.

Once those steps are complete, you can turn logic 7 on and off, adjust the center, balance, fader and sub levels, adjust bass midrange and treble and draw a new curve with the 31-band EQ. Since the channels have all been matched by the auto EQ, you only need to draw a new curve and it's applied to all the corrected channels.

THe subwoofer level control is a shelf that's applied to all the channels rather than an output level control for the sub amp. That's why no overlap or underlap is necessary in the crossover. This works great too.

Once setup is done, you can use MS-8's volume control or the control on the head-unit
______________________________________________________________

t3sn4f2 : 
_Just to be clear, Logic7 off with center active turns off the center output?
And if we have no rears/sides and have Logic7 on. Does the fade position matter? 
_
Andy Wehmeyer :
Yes. Logic7 Off is just Multi channel Stereo. Left is broadcast to Left Surround and Left Back, Right is broadcast to Right Surround and Right Back.Center disappears.
Even more general, if you have no rears/sides, if you fade to the front it has no effect. If you fade to the rear, it will attenuate all fronts
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Houstonshark : 
_Man I really wish the controller were small and slender like the Bit1 and I've never understood a remote in a car. Why weren't the controls built into the display?
_
Andy Wehmeyer :
So the remote control can be used in the back seat during setup if you measure in all seats and in cars where people are driven rather than driving themselves. The display was designed to be easily installed even when there's no din or half-din pocket. I'm sure it doesn't suit everyone.

This is a DIY forum, right? Make something custom...The screen can be removed for the housing pretty easily and the remote comes with a flush mounting cup. Additionally, the remote is RF rather than IR, so line of sight isn't necessary.

I think Biggs mounted the display in his rear view mirror--seems easy enough.


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## Tendean17

Andy Wehmeyer :
Here are a few rules that will hopefully set some folks at ease.

1. If you have a big center channel, time alignment doesn't matter. 
2. If you have a small center channel, time aligning the midbass in the doors will be helpful for one-seat optimization. When "Front" is chosen, the midbass may be slightly biased toward the near side. This depends on the crossover point, but won't be a big deal.
3. If you have no center channel, the sound will be great in one seat at a time--like all TA-based systems.
4. Ambient noise isn't an issue during INPUT calibration. It isn't a big issue during acoustic calibration. You don't need to kill all the mice in the building. but it's probably not a good idea to calibrate next to a railroad track unless you can wait until the train has passed.
5. READ THE OWNER'S MANUAL. If you'll use a factory head unit, you MUST run input setup. If you'll use an aftermarket radio, you can skip that part. 
6. If the sweeps are too loud, you'll clip the mic inputs and the unit won't be able to determine arrival time coorectly and it will screw up the TA settings. USe a volume level (on MS-8) of -20 for the sweeps if you're using MS-8's amplifiers. If you're using outboard amps, it should be lower than that. If, after calibration, it sounsd strange and there's no center image, the sweeps are too loud. Recalibrate (acoustic only) at a lower level. The sweeps don't have to be loud. About the same volume as someone speaking to you while seated in the passenger's seat.
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Gearhead Greg : 
_So, if someone was to want only "Driver", then they could use the "done" option after the first set of measurements were taken, correct?
_
AdamS
Yes, and I highly recommend it. This will ensure that your baseline setup is OK.
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michaelkingdom : 
_Hi everyone, I've got the MS-8 running and I am very happy with the sound. It is excellent!! The only issue I am having is that the back speakers sound strange. With Logic 7 on, if I use the fader to play only the back speakers, the sound continuously gets louder and quieter, back and forth like a wave. It sounds like the speakers are being cupped and released. This can best be heard when I isolate the back speakers but when the system is balanced, it is not detectable.
When I turn the Logic 7 processing off, the back speakers work perfectly, with no volume stability issues. It only occurs with Logic 7 on.
I thought it might be the amp so I changed my amp and had the same exact issue through another amp.
Is the Logic 7 processing doing this on purpose?
Michael Sarasota FL
_
Andy Wehmeyer :
That's what Logic7 sounds like. There's nothing wrong with your system, but listening to surround speakers only isn't much fun. Think of it like this, you're only listening to the "echo" without hearing the sound that produces the echo.

That's not exactly what happens, but it's a good analogy. I think I posted somewhere the whole "how logic 7 works" diagram and explanation, but I can't go find it today.


----------



## Tendean17

james2266 : 
_I am curious of the answer to this as well. My plan is to upgrade my front comps and then move the current ones to the back likely. Don't know if I can get a center in my dash without some serious carving (not going to happen on a brand new vehicle under lease). My original thought was to just use the MS-8 power for the rears but i have heard others complain of a serious loss of output with this kind of setup. Is this the case and I should round up another amp or will the MS-8 power not cause this issue. I have 160 w rms going to midbass and 50 w rms going to tweets from an LRx 5.1k.
_
AdamS :
This is what I would try. During the pink noise sequence where you verify the channels, turn down the L/R amp until its close to the MS8 amp level.
Run setup, listen, make sure it sounds good, just not loud enough.
Increase the master volume until the L/R distort and then back it off. This is where you might think you're stuck, but you're not.
Next, fade to the back almost all the way (say 9 dB, we don't want to turn the fronts off).
Increase the master volume by the same amount. This will bring the fronts back to where they were almost clipping, but bring the surrounds/rears up.
Lastly, turn up your front amp up by 9 dB to compensate for the fading effect.
You have just regained 9 dB.
You might be able to increase your amp by even more than 9 dB, but you'd have to experiment.
______________________________________________________________

Andy Wehmeyer :
OK... the rears in L7 play loudly or not so loudly depending on what information in the track gets steered to the rear. On some tracks, there won't be much output on others, there may be a lot. Ideally, the rears would be able to play as loudly as the fronts for those times when the recording dictates that they should, but this isn't super critical. 
When MS-8 does the calibration, it looks for the rears to be about as loud as the fronts--it level matches them. If you amplify the front and not the back, MS-8 will reduce the level of the fronts. That means that if you've paid for 1000 watts for each of the front speakers and don't want to buy an amp for the rears, you won't experience Logic7 as it's supposed to be experienced. If this is an acceptable compromise because you don't want to buy an amp and you want the front speakers to be loud, then do this:
Turn the gain down on all of the channels that are amplified by outboard amps. Run calibration. Turn the gain on all the outboard amps up by the same amount until you're happy with the overall level. Listen to music. Adjust the fader towards the rear until you get a level of ambience that you're OK with. Listen to lots of different recordings. If you have to move the fader most of the way to the back in order to be happy, thereby attenuating the front, then you'll need to buy an amplifier for the rears to get the level you require from the front and still maintain the front/rear balance that you like. 
That's the best way to manage the compromise and to figure out how much power you need for the rears. Think of the output of the rear speakers as a condiment for your sandwich. The Front right and left are the two slices of bread and the center channel is the meat and cheese. If you're a vegetarian or a vegan, this analogy doesn't work for you, so you'll have to do a bit of interpreting.


----------



## Tendean17

Bikinpunk :



bikinpunk said:


> alright, here a few things I noticed tonight:
> 
> 1) Setup is unbelievably easy. I did the input setup to find a good headunit volume to set things up at, which wound up being around 32 out of 40 on my pioneer z110bt and set the ms-8 output volume to 35, iirc.. Within 5 minutes I had already ran driver setup, and acoustic calibration for both front seats. The on screen directions make it kindergarten easy.
> Additonally, volume is not a problem. I re-ran setup with the headunit volume a bit lower, and with the ms-8 volume set at about 25. Plenty of volume and no audible distortion, at least that I can hear.
> 
> 2) When the setup tells you to look at x mirror, do it. I tried toying around with this and the further away I looked out (past the mirror), the more the center was skewed. If you look exactly at the mirror, as told, you get a DEAD center phantom.
> 
> 3) Andy was talking a mean game about this whole subwoofer integration thing. I honestly thought the man was full of it (no offense, Andy). He speaks the truth. The initial setting leaves some to be desired for me, so I up'd the bass output. It NEVER pulls to the rear. Not even at full friggin tilt. Sub/midbass crossover is at 80hz, 24dB/oct. I'll try 60hz later for fun. But I like 80hz for the safety of my drivers...
> 
> 4) Speaking of which, everything sounds great. Rap, rock, jazz, whatever. So far everything sounds very nice. I've only bumped the 'bass' up about 3 notches. Still solid impact.
> 
> 5) System Noise: None. Although, I had very little with the bitone. I did have some noise floor. I can't hear anything of the sort now with the ms-8. Maybe it's magic? Who knows. I do know that I can get to the same volume (actually, a bit higher now) as I could with the bitone when it's outputs were max'd so that tells me that _something_ in this stream has a higher output and even with that, I have no system noise (crossing fingers for when I turn the alt on... in the garage, can't check tonight).
> 
> 6) Alright, my music collection varies and I use a lot of stuff to demo systems (not very traditional stuff either, but so be it). Here are my thoughts on the ms-8 5 minute auto-tune vs. my own bitone manual tune which took a few months to get to where I was really happy:
> 
> Rage Against the Machine "Take the Power Back":
> Kick drum echo! woohoo, baby! It's there! Do you know how LONG it took me to get ambience of that kick with my own tune? Seriously! wtf!
> Bass guitar/kick: Very easily identifiable as separate. This is tough to do. A lot in the midbass/subbass has to be right to get this separation because both are centered right up front. If the system you're listening to isn't set up well, you'll get the two instruments confused (ie: why does that bass guitar have so much punch?! )
> 
> Dire Straits "Walk of Life":
> The beginning of this track has cymbal taps that have different tonality. I've worked really hard (and listened to some higher end gear in a local recording engineer's house) to make sure this is right. The ms-8 does it perfectly ... or as perfect as I can tell. The taps walk about 2-3" apart, as I believe they should, and have a distinct tonality. I've rarely been able to tell this and I listen hard for it in other systems.
> 
> Norah Jones "Chasing Pirates":
> At the beginning of this track there are (what I call) the sound of bubbles... yea, horrible description, I know.
> Anyway, typically this is very faint and, in my car, they sound to be coming to the left of the stage. With the ms-8 they're closer to me but yet _still_ further outside of the car. I was left  as to how it got this, but hey... I'll take it.
> 
> Eric Clapton "Layla (Unplugged)":
> Pretty well known song, I believe. The guitar at the beginning has a lot of picking going on. I could hear detail in the picks that I hadn't heard before such as: resonance of the strings themselves - hope this makes sense, because resonance in the strings is how we get the sound, but I'm talking about abruptly stopped strings - and they have more body to them. Never noticed that with my other tune.
> 
> P.O.D "The Messenjah":
> This song has a lot of stuff going on it. Not a reference track, by any means, but one I really love.
> Sonny's voice shines clear through and you can almost _feel_ the passion when he's screaming through the chorus. The music breaks down a lot in this song and everytime it does, the system does an excellent job of keeping up (transients). I've been listening to this song on HEAVY rotation the past week and hadn't noticed it before. Not saying the ms-8 is doing it, but it's something I've never noticed before.
> 
> Peter Gabriel "Sledgehammer":
> About 22 seconds into the song, right as the flute (presumably) stops and right before the music really kicks in, there's a bit of silence. In this bit of silence, I've never heard anything. But, now I can hear the song's intro _right before_ it really starts. Sounds crazy, I know. I've listened to this song about a million times... or so... and I've NEVER heard this before. Ever. Scary!
> 
> Natalie Merchant has never sounded so wonderful. The stand up bass in "Carnival" is the best I've ever heard it.
> 
> Last but not least... the thing that made me literally say 'WTF' to myself as I was listening..
> Alison Krauss & Union Station "Man of Constant Sorrow (Live DVD Version)"
> I know this performance well as it's a favorite song of mine, so I've heard it on many different systems. Having said that, I've always heard the singer as being centered and singing outward. Alright...
> About 15 seconds into the song I thought I heard his voice shift as if it was facing the right side of the stage. He says "I bid farewell to ol' Kentucky" and I SWEAR I thought he was singing to my passenger. I couldn't believe it... I came inside to check the DVD and sure enough... he's facing the right side of the stage (his left). I about crapped a brick. I heard his voice shift around as he was moving his head. I've NEVER heard that before. I'm sold.​
> 8) Stage width is at least as good as I was able to get on my own. On a few tracks, I noticed it was clearly wider.
> 
> 9) Stage depth is a little bit better, but not a whole lot.
> 
> 10) Stage layering (front to back instruments/singers) is better by far than it ever was. It is very evident when a musician is behind another or back and to the side. My previous tune didn't do this too well. There was a lot of blending. Now there is clear separation.
> 
> 11) Finally, to you guys who like to drive looking at the car next to you: you can turn your head a full 180* and the stage stays put. There's NOTHING I've ever heard that would do this. :thumbsup:
> 
> 12) The remote is very nice. Ergonomic, it is (/yoda). Getting around the options, etc on the screen via the remote is very intuitive and extremely easy. However, I've noticed some minor lag, but nothing major at all... barely worth noting (seriously) but for full disclosure, I'm noting it. I associated it with RF (as I assume it's not IR) lag. I get that inside my house with my TV remote, lol.
> On the plus side, you can pretty much point it anywhere and it works. +1. I love remotes.
> 
> 
> I'm going to do some listening from the passenger's side tomorrow. I plan to also take some measurements on the preouts and system FR via RTA so I can see what the MS-8 has done to the signal that has worked so well.
> 
> I'll try to get a review up sometime in the coming days. I guess now that this is installed and tuned, I don't have anything to do tomorrow.
> Which actually brings up a rant. I imagine, now that I no longer have to manually tune my car a few hours ever couple weeks, that I'll now have to start actually doing something else like doing laundry or cleaning dishes. Man, this sucks.
> Of course, my wife will probably be sending JBL a personal thank you letter.
> 
> Edit: Added a few last minute things...
> 
> *Cliffs:*
> This thing really is the bees knees.


Bikinpunk :
as someone said, you can see my extensive install thread, full of wins and fails. I document it all in hopes someone can learn from me.

Anyway, here's my setup:
Headunit: Pioneer AVIC-Z110BT
Tweeters: Hertz ML 280 signature on dash
Midrange: Scan Speak 12m on dash
Midbass: Scan Speak 18w in kicks
Subs: Acoustic Elegance IB15
Tweeter/Midrange Amp: JL Audio HD600/4
Midbass Amp: JL Audio HD600/4 bridged
Sub Amp: JL Audio HD750/1
______________________________________________________________

Tendean17 :
Bikinpunk's Review at :
http://www.diymobileaudio.com/forum/product-reviews-erin-harrdison-bikinpunk/83066-jbls-ms-8-a.html


----------



## Tendean17

npdang :



npdang said:


> I didn't have a chance to play with this for more than two afternoons, but I did manage to come up with some quick impressions of the device. Unfortunately I didn't have rear speakers so I wasn't able to test Logic 7. My experience with BMW logic 7 is that it sounds terrible, but I'm sure that's more to do with overall system setup and equipment than logic 7 itself.
> 
> 1. Like many others here I'm sure, I don't mount the display unit as I prefer to keep a stock interior and I wouldn't be looking at it anyway unless I was tuning. That being said I would have preferred to have an integrated display/controller device that can tuck away, rather than a separate remote control and display. I'd find myself sitting there holding the display in one hand and pushing buttons on the remote with the other, which feels a bit odd.
> 
> 2. The size of the unit is problematic for me and I'm sure for others as well. I could not find anywhere discreet to mount it, and ultimately no matter how much I might have liked it I couldn't keep it because of this fact.
> 
> 3. No independent channel/driver level output controls. I found that I still needed this to achieve the level of tuning I prefer.
> 
> 4. Auto-tuning appears to be very gain sensitive in my experience. If you're running your sub or mid gains a bit higher like most of us tend to do, I believe it messes up the auto tuning big time. I'd get a really off centered stage with almost no ambiance to the left. Also, if your gains are set too low (say to avoid hiss), you might lose a lot of output after auto-tuning is done. There might be other situations as well where the ms-8 for whatever reason doesn't like where your amp gains are set, and you will tend to lose significant system output.
> 
> If the auto-tune doesn't sound right to you, chances are playing with the gains will fix the problem. Just make sure that after auto-tuning is done, the gains are set back to the same relative position for each channel otherwise it will obviously screw up the level balancing for each channel. Easiest way to work with the gains is to find what works before auto-tuning, and leave it there.
> 
> 5. Tonally, I believe I can still do substantially better than the ms-8's auto tune over time. Can you? I don't know. To me, it sounded like a good stock system tonally but with better drivers and more power. Which is high praise indeed don't get me wrong, but for me I had that tiny hope that it could surpass what I was capable of (I know unrealistic).
> 
> 6. Staging and imaging is stable and locked in. I think this is the best part of the auto-tuning. You're pretty much still limited by driver location and vehicle acoustics, but the ms-8 will pretty much do in 1 minute what I can do in a day or a week and I'm sure better than what most people could achieve on their own. I didn't try testing for more than one seat though. Also, some people like myself prefer to have the image centered in front of the driver. It would be nice to have that option. Playing with the l/r fader controls can move the stage, but it seems to mess up the auto-tuning a little bit and you lose output.
> 
> 7. Bass is upfront and well blended without missing holes or peaks in the response. I didn't find it to be too anemic, although I'm sure 99.9% of the people out there will. This is really where your bass should be if you're a purist. Completely invisible and no sense of resonant bloom, overly strong undertones or exaggerated midbass kick/punch. Just seamless, close to perfect bass. No adjustments needed here.
> 
> 8. Treble is generally unoffensive although I found it to be a bit forward in the upper treble region. Working with the EQ took quite a bit of time, but eventually I could get it ~90-95% where I wanted. See #3 above as well.
> 
> 9. Midrange is where I was disappointed. The ms-8 removes significant lower end midrange resonance which is good (because most people suck at doing this right), but tonally to me it sounded "hollow" and kind of clock radio-ish. You can play with the 31 band EQ to tweak to taste, but after a few hours I still couldn't get it close to where I wanted. Maybe after a few months I could have gotten it exactly where I have it with my PPI DCX730, but again the PPI setup also took several months of tuning to achieve. The PPI obviously has quite a bit more tuning control, but whether the ms-8 could eventually achieve the same result I don't know. I'd like to think it could, but obviously there are some response shapes that you simply can't draw with a 31 band EQ that you can with an independent 7 band PEQ. What I really liked about the ms-8's EQ however, was that you could change the system tonally without messing up the staging/imaging like you would with traditional EQ.
> 
> For most people though, I'm willing to bet that the auto-tune is a significant step up in tonality.
> 
> 10. Bluetooth functionality. Appears to work fine for me. But I recall seeing that it doesn't work for some people. Just thought I would mention it.
> 
> Conclusion: Big thumbs up to JBL. For most people, after learning some of the quirks of the device (gains, tuning limitations) I think would be very happy with it. So far it is the best auto-tuning processor I've heard and is relatively straightforward and easy to use. If you're a picky/expert tuner, and you already have a setup that has been tweaked to perfection there is really no reason to buy the ms-8 unless you want to try logic-7.
> 
> **P.S. Bikinipunk you will probably recognize the ms-8's auto-tuning stimulus signal to sound very similar to Praxis's "chirp." Very fast and robust, and beats listening to a long ass MLS sequence or worse a swept sine.


______________________________________________________________

Tendean17 :
npdang's Review at :
http://www.diymobileaudio.com/forum...t-comparisons/84287-jbl-ms-8-impressions.html


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## Tendean17

Buzzman : 
_In order to "test" the MS-8 against the BitOne.1, and do so fairly, you will have to at least replicate the EQ executed by the MS-8's auto tune. ...If you read Erin's (Bikinpunk's) review, I think he makes it clear that more than anything else he is attributing the results of his listening experience to the MS-8's tuning capabilities, which he has concluded are superior to his.
_
Bikinpunk :
Initially I was going to get the ms-8's curve to reflect my final, manually tuned, curve. Then I thought about it a bit and realized "whats the point". Right?
For one to TRULY give an apples comparison you'd have to mimic, to a 't', the DSP effects. When you're talking about phase, t/a, etc there's so many ways to get the same overall curve. A simple example is to take your setup, change the crossover slopes, and then EQ to get the same response. It will not sound the same: period. There's just about no way for me to do the exact same thing since I don't have access to the t/a or phase... and that's just the minimum things I'd need.
I mentioned that I might throw the ms-8's outputs on my RTA and measure the FR of the preouts, but I'd only do so just for my own curiosity to see what the EQ curves look like.
Although I don't have the knowledge most do of how DSP's work, I do have a basic understand of the relationship of phase to t/a, crossover slopes, and EQ bands. I know enough to know that I can't replicate my bitone settings. So, there's no point in bothering. Therefore, there's NO way I can say that the ms-8 is better than the bitone. I can only give subjective opinions on it's ability to auto tune a system vs. my own ability to tune.
______________________________________________________________

Buzzman : 
_I have heard 2 MS-8 based set-ups. One I would characterize as a work in progress because the MS-8's capabilities were limited, in my view, by speaker placement choices that adversely affected the auto tune process.
_
Bikinpunk :
This is where we'll just have to see how it plays out. I tell you one thing, I've re-tuned my system via the auto-tune 8 times now. I've been experimenting with head position, having a second person in the car with you, and a few other things to see just how much the tune changes, if at all.
Right away I can say this: the degrees you turn your head during the 'look toward x mirror' will effect the staging. 
The great thing about the ms-8 is that it allows you to try these kind of things on your own VERY quickly due to it's ability to auto-tune in less than 1 minute for a single seat position and it'll keep the user applied curve if you choose to do any after-EQ. So, you can compare 'oranges to apples' with apples only. Wait... does that make sense? 

What I'm getting to is this: I'm realizing that the odds of everyone's car sounding 'the same' is hardly realistic. User 'error' will dictate results just as much as vehicle acoustics. However, there's surely a line where all cars exhibit the same type of response if they do the auto-tune and leave it alone. I'm willing to bet that all the cars would have the same type of sound (ie: laid back) although they'll achieve it differently and there'll be different details/nuances to each. This is only a guess. I hope to be able to use my ms-8 in a few cars just to test this out for myself, which leads me into...
______________________________________________________________

Buzzman : 
_But, the vast majority of music lovers just don't have the patience, time, or capability to optimally tune their systems, and based on what I have heard the MS-8 offers the easiest path to maximum enjoyment of our music and systems.
_
Bikinpunk :
Now, at the risk of having an ego (which, anyone who knows me knows that I do not), I have to say that I was very, very happy with my system with the bitone. I thought the tune was great. In this regard, I was a bit prideful, meaning that I wanted to do all the tuning work myself. Therefore, I did. My buddy Andrew helped me tune it last October for about 2 hours after I got the install set up the way I wanted to, finally. After that, I've only had people give feedback. No one else has manned the controls. Why? Because I wanted to do it myself so I'd know what to listen for and how to correct it the best I knew how. This has helped me immensely. In fact, this is my only real 'concern' about the ms-8 and future renditions being the new 'it' factor. I'm a bit worried (how condescending of me) that people will not really know what to listen for if they're not learning what exactly a certain change to X does. IE: You can hear phase 'click' into place when using t/a, but this is only for certain bands of response. When you don't do this yourself, you don't have the knowledge of what to listen for. Of course, it's great for those who don't care, but for folks like me who have gained a better ear because they tuned their own car manually, I feel that the ms-8 could serve as a disadvantage. It's a huge leap and likely not a big concern, but as I said... I have my reasons. *and this is NOT to say I have golden ears... it is to say that I've learned what to listen for because I had to*
I felt I was about 90-95% 'there' overall with my system. The only issue I had lingering was the midbass/subbass which I would have fixed because it was an install problem (thus my new IB wall this weekend). This should only go further to show just how good the ms-8 is. And with the EQ features, one should easily be able to tune their system to their liking. The way the ms-8 handles phase relationships is, IMO, going to be the wave of the future. It's not about EQ. It's about phase. I may be the only person who believes this, but given what I've learned the past year, I'd put my money on a processor that has the ability to adjust phase correctly. I honestly don't think a human can do it better in a car. Very bold statement, I know, and don't PM me with your hate mail, but what I mean is simply this: given a proper measurement/DSP system, a computer should be able to handle the ability to evaluate and correct phase issues. Besides, when we adjust EQ, we're adjusting phase anyway. 
It's hardly been touched on, but the way the ms-8 does it's thing - the binaural mics and spacial averaging - is the way we all need to be taking measurements in the car (and home). I'm just now getting on this train of thought; Geddes wrote a paper on it many years ago and a few of the vets here have been preaching it (or did when they were still here). This is, IMO, where the ms-8's enormous capabilities is rooted. 
What I would like to see is actual FR, phase, THD, etc plots of the ms-8 outputs and compare that with the bitone. That would be some really cool and interesting things to see for my own technical knowledge... which leads me to...


----------



## Tendean17

Buzzman : 
_In order to "test" the MS-8 against the BitOne.1, and do so fairly, you will have to at least replicate the EQ executed by the MS-8's auto tune. There will be a rash of efforts comparing the MS-8 to the BitOne.1 (and a lot of interest in such comparisons), but they will be of little merit if they are not apples to apples comparisons. I asked Andy in an earlier post whether the results of the MS-8's auto EQ can be determined by the user, and his response indicates that it can be done, though it will require a good deal of work. If you read Erin's (Bikinpunk's) review, I think he makes it clear that more than anything else he is attributing the results of his listening experience to the MS-8's tuning capabilities, which he has concluded are superior to his. I have heard 2 MS-8 based set-ups. One I would characterize as a work in progress because the MS-8's capabilities were limited, in my view, by speaker placement choices that adversely affected the auto tune process. I was very impressed with what I heard in Big Red's truck, and he too has given kudos to the MS-8's tuning capabilities. I love my Bit One, and don't have any plans to dump it. I am one of those (soon to be turned into dinosaurs by the MS-8) who enjoys the hands on experience (and education) of hearing what changes in filters, crossover frequencies, slopes, phase, etc. have on what I hear when music is played back._

Bikinpunk :
I'm right there with you, man. In fact, it's the major contributor to why I change gear so often. It's not that I'm disatisfied with my system, or expect to be able to do better with certain gear (not always the case). It's mainly just that I want to toy around with something new, play, and learn (thus my quote). 
I don't do well sitting on the sidelines. I don't like taking people's 'word for it', though that's not to say I don't appreciate reviews and factor in those opinions on some purchases. 
I don't do this stuff to be an 'internet hero' as I've been called. I do this to learn and to contribute what I learn. I work with many people who can read a book or instruction manual and know exactly how something works by doing that alone; I don't do that. I've tried. I get distracted and start thinking about cookies and milk, or how I need to cut my toenails... whatever. I have to get hands on to learn something. I buy new gear to learn and sometimes put my own thoughts out there hoping others can get something useful from it.

However, in this case, my skepticism is what lead me to desire the ms-8. I didn't want to take someone's word for it (no offense, guys). I didn't think it could do what I did and no way could it be better. I was wrong. But don't think that I won't stop fiddling with things. I've already got plans for future listening.

As I said earlier, my door is open to anyone just about all the time. I'd be more than willing to let anyone demo my car or possibly arrange for you to demo the ms-8 in your own car. 

Thanks, Buzz, for reminding me of some of these topics. I saw a frog on my garage wall earlier and forgot everything I intended to remember. I took pictures of it, too. 
______________________________________________________________

Andy Wehmeyer :
Is an apple better than an orange? It is for me because I can't eat oranges. 

The lesson I learned in developing MS-8 is that there are basically two kinds of audio nuts--those who love to listen and those who love to tinker. This site is for audio nuts, not regular Joes. In order to build a great product for you guys, I have to make it appeal to regular Joes too, because there aren't enough audio nuts.

When we started, I told the engineers that I required a back door to the filters because I knew I could do a better job. That was crap, but only partially. Can I do better? Yes, but I have to have a lot of time, a serious analyzer, 10 times the processing power and a bunch of tools that MS-8 doesn't require and that AREN'T AVAILABLE IN THE AFTERMARKET. So, is MS-8 better than me and those tools? As a product that can be sold and implemented by a normal person in a reasonable period of time and for a reasonable cost? Absolutely. 

The second thing I learned and am still learning and am hoping to help others learn is that much of the audio babble that so many in the industry spout isn't useful. Is .0000001% THD better than .1%? Yes. Does it matter? Not really--it's damn difficult to hear. Are uber-high-end DACs more accurate than run-of-the-mill DACs? Probably. Does it matter? Not really--it's damn difficult to hear. Are $10,000 speakers that are driven with a measly 50 watts more accurate than $100 speakers driven by the same amp in a car? Probably. What about after EQ-ing for room correction? Does the difference in the speakers matter? Not really--it's damn difficult to hear. 

Do I believe that "Good-Enough audio" is good enough? Hell no. But the average experience isn't even close to good enough. 

In my 25 years of working in this industry, I've listened to thousands of cars and I can count the ones that sounded great on two hands. Most of them have serious problems and some of the worst ones are IASCA winners. In fact, I'm in China doing a 4-day audio training for a bunch of dealers. Many of them have brought their cars, so we're having a tuning session each afternoon. 50% of these guys have plans to change all the equipment in their cars because they don't sound good. In every case so far, none of the equipment has been the cause of poor performance. In every case, it's the installation, the adjustments or the system design. All of these cars have cool fiberglass boxes, amps, components with tweeters mounted in reasonable locations, but they all sound like ASS except for one. THe one that sounded great was the simplest system of the bunch but the guy had actually set the crossover points correctly. 

Can I fly all over the world constantly teaching everyone that they have to turn the knob and listen? No. Can I build a product that allows installers to do only what they want to do and to still build cars that sound good? I can't, but with a team of others, we can...and we have. That pays the bills and makes it possible for us to incorporate at least some of the things that audio nuts require. 

I've explained a thousand times the differences between BitOne and MS-8. One is a toolbox and the other is a carpenter. Thankfully, there's a choice because if the audio industry only caters to audio nuts, there won't be much of an industry left and the only companies that will be able to afford to continue selling gear will be the ones that can't afford to innovate. Making outlandish claims about passion and high-quality parts isn't innovation. If those are the only companies left, you won't even have a toolbox. You'll have a bone chisel and a rock.

Sometimes you feel like a nut...sometimes you don't.

Here's the deal. In less than 2 weeks, we've sold 473 MS-8s and 25 have been to DIY people. I love you guys and you make this fun for me. The other 450 make this possible.


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## Tendean17

Boostedrex : 
_So, out of those guys who are currently running these... Were you pleased with the staging/imaging in your car after the quick auto-cal from the MS-8? Or did you feel it needed further tweaking? Just curious as the few guys I've talked to sounded like they LOVED what the auto tune did.
*And yes, I'm purposely trying to steer this back on course. Please take the hint everyone.
_
Bikinpunk :
did you even read my review? LOL! 
Here's the deal: the center (without a center channel in my car) is dead center. I can turn my head to the side and it stays put. I can move my body about 1.5ft forward... well, actually all the way up to the dash (and you know how far back I keep my seat as you've sat in it) and it stays centered. Only when I move about a foot to the right does the center start to move with me. 
I love this thing. Seriously.
______________________________________________________________

Andy Wehmeyer :
If the staging sounds strange after running acoustic calibration, the sweeps are too loud. Turn down MS-8's volume control and run calibration again.
______________________________________________________________

kaigoss69 : 
_So the internal amp channels are not well suited for use in active set-ups I take it.
_
AdamS :
The recommendation is to either run all of the Fronts (L/R/C) off of the internal amps or all off of external amps.
If you mix and match, you will possibly have EQ limitations and will definitely limit your potential output power.
That being said, you can easily run the sides and rears off of the internal amps and the fronts off of external amps.
______________________________________________________________

kaigoss69 : 
_So the internal amp channels are not well suited for use in active set-ups I take it.
_
Andy Wehmeyer :
The internl amps are fine for active or passive setups, but they're 20-watt channels at 4 ohms. Driving front midbass and midrange speakers with 100 watts each and using 20-watts on the tweeters just doesn't make a whole lot of sense, unless the tweeters you choose are 7 or 8 dB more efficient than the mids and really are 4 ohm tweeters. I have a car full of these same chip amps--24 channels, to be exact and it's 100% active.
______________________________________________________________

Bikinpunk :
_I had messed around with logic 7 a bit at first at didn’t notice anything really different so just left it on. 
Then…
Answer: Logic 7. 
Listened to a Madonna track today titled “Live to Tell”.
MySpace Player

At different parts of the song, there are (what sound like) key that play. You hear them at the beginning of the track @ 0:23 seconds and a few other times throughout.

With logic 7 on the keys don’t sound right. It’s like they’re being cut out.
With logic 7 off it sounds fine.
_
Andy Wehmeyer :
Logic 7 steers out of phase information to the rear and it samples the music every few fractions of a millisecond. The only channels that are affected by the front and rear steering are the rears and sides. IF you have a center, leave L7 on and fade to the front if you don't like the front and rear steering. L7 isn't perfect and there will be some songs that break the code, but on balance, I think the effect is better than not having it.
______________________________________________________________

Andy Wehmeyer :
Oh, several of you have asked about the effect of diferent mic angles on the result. 

Here's the scoop. The first measurement in each seat is for TA. The processor uses the average of the two mic placements, essentially the point midway between your ears. You should look straight ahead for that measurement. 

The second through fourth measurements are for frequency response. The difference in the response between the mic that's closestt to the speaker that's being swept and the one on the other side of your head is head masking of high frequencies. If you turn your head really far for the third and fourth sweeps, there will be less high frequency content in the measurement and MS-8 will EQ the treble accordingly. At much lower frequencies, there won't be much difference. If you're using tweeters in the sail panels, you'll notice a difference between different head angles, as frequency response from the tweeeters affects localization at high frequencies. If your tweeters are in the KPs, there will be less difference.


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## Tendean17

Andy Wehmeyer :
The Microphone MUST be unplugged after calibration is complete. The microphone is multiplexed on channels 4 and 8 and there's some leakage at low frequencies. This isn't a problem, unless you leave the mic plugged in. This is why the display reads "Unplug the microphone" after calibration is complete. Or at least I think it does.
______________________________________________________________

Andy Wehmeyer :
Guys,
My mistake. The display doesn't say to unplug the mic. The manual and quick start guide do, though. In every instance (3) of jet engine noise, the mic was plugged in and the subwoofer sweep seemed to be WAY TOO LOUD. Our verification team is now on this and I expect they'll find the cause soon. We're also working on the bluetoth issue.

Regarding the microphones: They are WM61 clones (since Panasonic no longer supplies those mics). THe reason that those are so popular is because they are so closely matched without a bunch of additional work. The correction file does correct for an average of severalmic capsules, but it also includes correction for the shape and size of the headphone plastic. Using another binaural microphone won't improve the results because the calibration file is designed for our plastic parts. The only difference between the headphone style and an in-ear style would be at very high frequencies. To be absolutely correct, the target curve would then have to be modified to account for that difference. 

Developing a binaural microphone, a correction filter for it and a target curve that takes all that into account and achieves a desired result is no small feat and has taken months of work in correlating listening tests, measurements with standard micropones and microphone arrays using a dummy head in the car and in a chamber. I'm not inclined to make that work public or to make modification easy, because we won't be able to assure good performance if we do. 

In all of the emails and PM's Adam and I have received, there's one theme that is consistent--that the target curve is good for the vast majority of people and that the autotune, which is the most important feature, provides great results when a few rules are followed. 

I can't reiterate often enough that if the sweeps are too loud, the results won't be good. The sub sweep should definitely NOT be loud--no rattling of the trunk or bass you can feel. Just a simple low-volume sweep. If you want more bass than about 9dB above the rest and you have the subwoofer level control maxed in MS-8, then adjust your sub gain AFTER you do acoustic calibration.

And for God's sake, please unplug the mic when you're done. You can use an extension cable if you want to. 
______________________________________________________________

Andy Wehmeyer :
The user adjustments aren't used during the sweeps. So this is no problem. 

I should add that the target tuning is designed to provide the illusion that the bass in up-front. Of course, it takes more than just EQ to do this. The levels have to be right, the woofer shouldn't make a bunch of high-frequency distortion and there can't be a bunch of rattles when the sub plays. The sub control is designed to preserve this illusion insofar as it is possible while adding a bunch of bass. If you don't care about that illusion and require much more bass, the appropriate and most successful "user adjustment" is to increase the gain of your subwoofer amplifier AFTER the autotune has done its work. I can't stress enough the importance of doing auto calibration at a low-enough level.

There is no subwoofer sweep during the first set of sweeps because we don't time align the subs--it isn't necessary and it's damn difficult to do with a peak picking algorithm. If the sub sweep is too loud during the frequency response measurements, then the sub EQ will either load an erroneous file or it won't EQ, depending on the error. There's no advantage to EQing at the loudest possible level and the range of appropriate levels is really wide. The measurement is also nealy impervious to extraneous or ambient noise (within reason), so this isn't something that has to be managed carefully during calibration, so long as the sweeps aren't too loud. I don't recommend parking next to a train track and calibrating as a freight train passes, though. Finally, all the sweeps are normlized in the algorithm, so the results of EQ at different but similar levels will be similar. The difference between a loud sweep and a soft one may be a different set of filter coefficients, but the result will be very similar. If you're noticing a big difference, then the sweeps are too loud and you're probably maxing out the available boost or cut. 

Finally, if you're using outboard amps and one band of frequencies is much louder than the others, then the same thing may happen--you'll max out the boost or cut or the unit's ability to level match. The window is wide, though--there's plenty of boost and cut available. If you're using outboard amps, I suggest setting the input sensitivity of all of them for about 2V and letting MS-8 do its work. If that's not loud enough for you after calibration, turn all of the amps up by the same amount.


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## Tendean17

Bikinpunk :
FWIW, I did some testing this weekend.
I swapped 2 different pair of tweeters in my car and tried them both on and off axis. After each swap/reposition, I re-ran the ms8 setup. Crossover points stayed the same; I just re-ran the acoustic calibration. 
The ideas that the ms8 will cause every car to sound the same was proven false. The car sounded different each time. Most notably between the speakers used. Not so much between the aiming of them. And I don't need blind testing to hear the difference in top end detail... we're talking obvious differences here. And the overall curve is still the same; but the results I obtained were still different from driver to driver. Now, tonality? I haven’t proven that because I haven’t tested different mids (I don’t really attribute tonality cues to a tweeter in most cases… maybe I’m wrong but that’s just me). 

Furthermore, my friend had his tweets in the sails. I listened to it the other day and there was pull to the left and what sounded like some phase issues going on. I attributed it to location, somewhat, but mostly the fact that 1/3 the diameter was being blocked by the tiny factory tweeter hole in his g37. I suggested he put them in the pillars to see if it helps. He said the center is now where it should be and there’s no more phase issues. 

I’ve managed to prove consistency in final output of the same system in the ms8 by doing MANY acoustic cals in the past, so I don’t factor in that as a contributor to the different sound. And, even if you did, the bottom line is that it sounded different each time.
So, as great as the ms8 is, it’s not going to make every car sound just the same, nor is it going to fix a bad install. 

My $.02.
______________________________________________________________

AdamS :
Debugging Tip of the Day:

If you're getting speaker "break-up" distortion, one thing to try is to pre-equalize the gains on your amplifier going to each driver. 

This way, MS-8 focuses more on the dips and bumps and less on level shifting sections of the spectrum. MS-8 does have gain and attenuation limits, and these can be hit in some cases, causing really odd results.
______________________________________________________________

alachua : 
_Should we just be focusing on L/R balance, or on balance between each mid/tweet driver?
_
AdamS :
For EQ break-up artifacts, just the lo/mid/tweet on a per speaker basis. MS-8 eqs one speaker at a time. For almost all cases we have seen, MS8 handles the entire correction by itself, but we have encountered a case where pre-equalizing the drivers resolved a problem.

If you also level match left/right/sub(+9dB), you'll find you get more digital headroom (can go up to maybe -5 or 0 dB) at the expense of analog headroom. 
______________________________________________________________

xr4tic : 
_I thought I read the opposite somewhere in this thread, that it's best to power the mids/tweeters with the same power, unless you have some super-efficient tweeters, or else run the risk of dragging down the rest of the system to their level.
_
AdamS :
I wasn't giving a rule of thumb, just some advice on how to resolve a particular issue. You will lose some gain in this case. In all liklihood, you would just need to bring the gains a little closer so that the system falls within the range of the max gain/attenuation. And like I said, that isn't common.
______________________________________________________________

chadillac3 :
Ok, one happy camper here. Here's what I'm going to say as a summary:
LEVEL SETTING IS ABSOLUTELY KEY WITH THE MS-8
As Bikin mentioned, gain structures matter very, very much. You need to get the relative driver levels all fairly close to get this unit to work it's magic. I took a Rat Shack digital SPL meter, c-weighted, fast response, and took MAX levels during sweeps (highest reading during a 1 s increment).
For the first sweep (t/a is set here), all my levels were within a couple dB of each other, around 75 or so dB. I couldn't write them down quickly enough before the next driver was tested, but I watched the screen. At most a 3-4 dB difference. This is with the unit set at -16 dB.
Now, for the 2nd-4th sweeps, here is what I read:
L R S
77 81 90*
77 80 90*
77 80 90*
*meter was peaked out, so probably a couple dB higher based upon my 2nd set of results.
L R S
77 76 89
75 86 90
72 76 89
Now, my vocal staging is absolutely fantastic now, and tonality is that much better. Hard to believe it can sound this good with fairly low end CDT drivers and the stock locations. Wife said it was the best any car of mine has ever sounded.
Now, one issue I have is too much bass, and I'm betting if I jack the gain up on the front stage (sub is already set at minimum) that it'll get just that much better.
For those having issues, I'd highly recommend investing in either SW to do SPL readings or a Ratshack meter. I firmly believe my issue was a relative setting issue rather than clipping the mics.
Unit set to -19 dB


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## Tendean17

Andy Wehmeyer :
C pillars are good. If you use sides AND rears, then you'll have access to both side and rear in the setup menu. If you're only running one pair of speakers in the back, you enter those as sides and enter rear as "none". MS-8 knows what to do after that. "Rear" is only available if "Sides" are chosen first.
______________________________________________________________

AdamS :
Debug Tip of the Day:

Using the Test Menu. I thought I would just publicize it since I have had to give it out to a few of you anyways. We never intended to make this accessible to end users, and you won't find it in the manual. So please only use it if you really need to, and be careful, as there are no crossovers protection your speakers and the volume is not controllable by master volume.

1. Go to the main menu
2. Hold down the left arrow for 2 seconds
3. Hold down the right arrow for 2 seconds
4. Repeat 2 and 3 several times if this doesn't work. It's intentionally a bit difficult to use.
5. Now you have access to a Display Test (for pixels), a pass-thru test (useful for debugging), and Aux test, and a pink noise per channel test called 'Output Diagnostics'

Display Test: just flashes pixels on and off, not really relevant 
Pass-thru: Inputs 1-8 go to outputs 1-8. Make sure your source volume level is way down. The DSP runs at 0 dB during this test and volume control doesn't work here. Don't use this test with a tweeter, as crossovers are also not used here. It's literally pass-thru.
Aux: Aux Input goes to Output 4/8. The other channels are pass-thru. Same precautions apply.
Channel Diagnostics: Pink noise for any channel. Again, no crossovers, no volume control, so turn your amps way down if you plan on using this. You might be able to use this to compare levels if you have some built in crossovers in your amp.

After using this Test Menu, *Do Not* hit back and then Calibration. You need to turn off Remote In and the turn Remote In back on before doing a proper calibration. 

Please PM me if you have any questions, but remember, 0 dB all tests and no crossovers.
______________________________________________________________

Andy Wehmeyer :
Marco, I'm glad it's working now. Processing on will usually be less loud than processing off, because the EQ prefers to cut rather than boost. This is a fundamental principle when equalizing. In cars it happens even more often, since the midbass and lower midrange is always too loud. If there's a big difference between the results after running input setup in your system, this suggests to me that the head unit includes some equalization or some channel delay. 

Covering the tweeters MAY improve imaging if:

1. The tweeters are ONLY covered during the FIRST set of sweeps for each seat
2. If the tweeters and the midranges are connected to a passive crossover and not driven by separate MS-8 channels
3. If the tweeters and the midranges are mounted in locations that provide VERY different path lengths to the listening position. 

It's a tip, but not a requirement.


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## Tendean17

Andy Wehmeyer :
OK. Measuring the acoustic output of the system with procesing and L7 off isn't particularly revealing of anything except some coarse approximation of what the system MIGHT sound like if the factory head unit had no EQ and included whatever crossovers you happen to be using to divide the signal to whatever speakers you've installed. That doesn't matter. If you want to find out the results of the signal conditioning part of MS-8, you'd need to measure the sum of the electrical outputs with processing off. 

My siggestion about not conecting the sub was intended as a solution for systems where adding the sub produces an overabundance of bass that can't be flattened by MS-8's EQ. Additionally, some factory systems include a hige overlap between the subwoofer's frequency band and the fronts. Adam's IS250 does this and it sux. Disconnecting the sub from the input helps that system a lot.

Also, if you're using a single microphone position to make these measurements, there's little chance that what you see is an accurate representation of what you hear above about 500Hz. Below that, it's probably reasonably representative of what you hear. 

Adam is right. If you want to measure the frequency response of the system, you MUST use uncorrelated pink noise. That will energize all channels through L7. Mono pink noise will steer center, so left and right will be attenuated and there will be no output from the sides or rears. MS-8's input signal conditioning is intended only to flatten the system so that L7 can steer effectively, That means that the midrange and high frequencies have to be reasonably flat and in phase. Correcting delay is far more important than correcting frequency response for this. The rest of the EQ may be fixed in the output EQ. What we hear is all that matters.

If you want to check MS-8's tuning against the target curve I've described, you'll need to replicate the measurement with some kind of binaural mic with a correction filter that would cause the measurement to correlate with a single mic in an anechoic chamber for a known and identical sound source. This isn't so easy. 

While I'm impressed with the effort on this forum to double check the accuracy of MS-8, there's more to it that measuring with an iPhone or a PC program and a single mic. 

VP Electricity is right. L7 affects the frequency response very little, although you may measure changes depending on the pink noise you use and the size of your center channel. Processing off eliminates MS-8's acoustic EQ and time alignment. Crossovers remain. 

If you really want to check input signal conditioning's performance, there's a way to do it, but you'll have to figure it out. For me to tell you would break my promise not to divulge the required testing method because of a certain challenge.

Marco, clearly, your system lacks bass. That may be because the subwoofer input isn't hooked up and it appears that the front crossover is about 100Hz and 2nd order. I suggest connecting the subwoofer output of your system to MS-8's input channels 7 and or 8 and running setup again. 

Finally, MS-8 doesn't include any dynamic range compression.

Yes, there will be differences in frequency response too. IF you have a center, you should notice some diference between the frequency response for Driver and Front, but the difference between driver and passenger will probably be pretty big when no center is connected. This is what happens when you have the ability to run throgh all the possible iterations instead of just one or two.
______________________________________________________________

mastermind : 
_Maybe, but, thus far, I feel the MS-8 is only doing about 20%, not 80%. My system sounds significantly better with processing and Logic7 defeated, leaving only it's crossovers in the signal path.
I'm attributing this to my lack of knowledge about how the product is supposed to work and my lack of experience in using it. Hopefully I can get smart pretty soon. 
_
Andy Wehmeyer :
I'd love to help answer the hidden questions here, but it isn't possible without more information. What aspects of the tuning don't seem right, to you? Also, what the rest of the system? MS-8 needs a baseline system that it can improve and there are a few things that it can't deal with. Speakers wired in reverse polarity is one condition that MS-8 doesn't fix. Frequency bands between amp channels (with external amps) that play at very different levels is another condition that can make MS-8 less effective. Finally, signal sweeps that are too loud don't work either. 

It's an autotune and the target is appropriate to win IASCA and MECA sound Q competitions and has made my customers happy for 25 years. The net is pretty wide. If you're like 90% of listeners, MS-8 should be damn close to pleasant for you. If it isn't, there are 2 options: 1) You aren't like 90% of listeners and the target isn't appropriate or 2) something in your system causes MS-8 to barf. 

If #1 applies to you, and you can't use the additional tuning tools to make it sound the way you want it to sound, then you should try something else. If #2 applies to you, try to describe the performance in terms that I can understand so I can help you get things going. 

I'm nearing my wit's end with some of these posts. It's like I'm passing out the juciest, sweetest oranges on Earth and getting responses like, "Damn, that orange was nasty. Well, it wasn't nasty. The inside was pretty sweet." 

To which I reply, "Hey, did you peel it before you ate it?"

And in response, I recieve, "I tried to disolve the rind by gluing pennies to it and soaking the whole thing in muriatic acid because someone on howtoeatoranges.com forum said that would work. The rind was gone, but it didn't taste good."


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## Tendean17

TheHatedGuy :
_I'm pretty happy with the base tune. I did do some tweaking to the low low stuff to get more bass without over driving the center (it's playing down to 65 hertz). I can run the seat all the way through the motions and get no noticeable difference in center position. The only thing was running the calibration with my arm rest up...WAY too much bass. With the arm rest down, the bass is great...even crossed at 100 hertz.

But to get the most out of this thing, you really really need to use all of its goodies- which means center and full range rears. I was playing it with the factory rears, but being they were biamped from the factory I was only using the midbass part...adding the tweeters back there further stabilized the image and height. Adding a good sized center...wow, now that is cooking.
You guys can't forget the basics of car audio even with as great as the processor is.
Next up is to do 3 way fronts...just to see what all Andy is talking about with beaming since I have 2 way fronts.
_
Andy Wehmeyer :
For the driver's position, the measurements made in the driver's seat are theonly ones that matter. same for passenger. For "Front", MS-8 searches for an EQ setting that most closely matches the target for both front seats. With a center channel and a little adjustment of the center channel level (up a notch or two), I've found that the center image is good in both seats. This is what Gary used to win SBN a couple of years ago.
______________________________________________________________

Andy Wehmeyer :
Ahhh...now we're getting somewhere. Turn the gains all the way down on your amps for this experiment. Check speaker polarity--especially front midrange. 

Try this--process of elimination:

1. Choose skip input setup, since you're using an aftermarket radio. 
2. Set up the system as a 2-way stereo system using only the front speakers.
3. Set the "subsonic" filter for the front at 30Hz and use your selection for the tweeters.
4. Run Acoustic calibration. 
5. Go into the Audio controls menu and turn L7 off. 
6. Listen and make sure you have a strong phantom center image. If you don't, re-run acoustic calibration at a lower volume level until you do. 
7. Listen for frequency response, but don't pay much attention to the bass. Once there's a good center, the frequency response of this should be good.
8 Add the Subwoofer. Your crossover points are probably OK. 
9. Run acoustic calibration at exactly the same level as before. The sub should be audible, but not loud. 
10. Listen again. If the frequency response sux, reduce MS-8's volume control and re-calibrate. If there's too much bass but the rest sounds good, try increasing the gain of the sub amp and re-run acoustic calibration.
11. Add rear speakers (sides in MS-8's menu).
12. Turn all gains up by the same amount until the system is loud enough and doesn't make a bunch of noise.
______________________________________________________________

jlee3 : 
_Andy, Still chasing this. I am getting better than stock but not near as good as I was looking for. So let me ask this another way. You have said that the MS8 can't fix a bad setup. I can start getting better speakers and add power but is a 9 inch midbass in the doors with a 3 inch mid in the dash doable for great sound? Or should I look to change the configuration...maybe a smaller midrange in the doors with tweeters in the dash or just put everything in the doors. Right now it sounds like the 3 inch speakers are over their head. But I don't want to chase my tail on this.
_
Andy Wehmeyer :
Try moving the crossover between the 8 and the 3 to something like 800Hz -1kHz and use 4th order slopes (24 dB/octave) everywhere.
______________________________________________________________

mitchyz250f : 
_It has been written that crossing you tweeters lower, let say 2500Hz or so will bring the sound stage up. Is this critical with the MS-8 with a center channel?
_
Doitor :
I've been playing around with different setups.
Right now, I'm using the tweeters up in the dash/pillar (L1 Pro SE's), Midrange/Midbass in the kicks (L8), center (HAT Imagine 6 in coaxial mode) plus the sub.
Tweeters are crossed at 4.5 khz
Mids play from 63 up to 4.5 khz
Center from 80 hz up
Sub from 63 hz down
All with 24 db per octave slopes.
Stage is high and flat. No rainbow effect.
Even if I turn Logic7 off, which turns the center off, the stage stays high.


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## Tendean17

Duper : 
_What do you guys think would be a better config? 
1) Active setup: MS-8 powering tweeters + 4channel 100wx4 amp powering door mid-ranges + 6x9 rear speakers
or
2) Passive setup: MS-8 to 4 channel amp powering passive crossover configured door speakers (tweeter & mid) + rear?
Thanks, Chris
_
Andy Wehmeyer :
Amp powering front in bi-amp, MS-8 on rear speakers. 
______________________________________________________________

Salami : 
_Andy, I can't find the exact post but you mentioned about using the crossover in the sub amp during the sweep to help deal with the peak during the sweep. I have a small sealed enclosure and am trying to to get a crossover point between 50-65hz with little success.
Are there any other options if the amp does not have a built in crossover? Can I put and external crossover in front of the amp during the sweep or will this make it worse?
Thanks
_
Andy Wehmeyer :
Try this: Rather than attempting to get an actual crossover at 55 or 60Hz, try 80Hz and 24dB/octave. Once the calibration is done, use the 31-band EQ to cut frequencies between 50 and 100Hz if the bass sounds too boomy and to boost below 50Hz. You may also want to listen carefully with the subwoofer connected in reverse polarity.
______________________________________________________________

thehatedguy : 
_I seem to remember Andy saying that too.
And to be honest, I don't know which way I like better. Seems like controlling the disspersion gets a more focused image but lacks ambience.
I don't know which I like better...but I do know I love the multichannel experience.
_
Andy Wehmeyer :
The point is that in a car, you CAN'T control the reflections enough. If you were able to eliminate them, then you'd have only direct sound. That's like listening in an anechoic chamber, which is a horrifying experience. 

The reason to "spread the chaos around" is because the listening area is so small, that we can equalize the sound of the speakers and the sound of the car with one set of filters, so long as the direct sound bears some resemblance to the reflected sound. The myriad of shapes and surfaces prevents these from being exactly the same, but if the reflected sound doesn't have enough high frequency content to be similar to the direct sound, then this EQ doesn't work very well. 

Take a 6" component system with a crossover point that's too high as an example. If the crossover is designed so that the on-axis response is flat, but the off axis response has a big hole at the crossover then EQ-ing for the average will provide a big peak in the on-axis response and a smaller hole off axis. 

There's no ambience in a car unless you create it using rear speakers and some delay. There is "spread" which is what happens when direct sound is combined with reflections and both reach your ears at about the same time. That's the reality of small listening spaces. With horns, there's less spread because there are fewer high frequency reflections from boundaries that are ADJACENT to the mouth of the horn. The reflections from the boundaries near your ears and behind you don't contribute ambience because the car is too small, but they do alter the frequency response.

Widebanders are good when you want to build a super cheap almost full range speaker for a dollar. That's what they're for--cheap computer speakers. They have no place in a high-quality audio system. They have wide dispersion at low frequencies and narrow dispersion at high frequencies (relative to their diameter) just as all speakers do. Asking if they're good enough is a little like asking if putting only a little rancid ketchup on your burger will really make it taste bad.


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## Tendean17

*System Noise
*
Bikinpunk :
None. Although, I had very little with the bitone. I did have some noise floor. I can't hear anything of the sort now with the ms-8. Maybe it's magic? Who knows. I do know that I can get to the same volume (actually, a bit higher now) as I could with the bitone when it's outputs were max'd so that tells me that something in this stream has a higher output and even with that, I have no system noise (crossing fingers for when I turn the alt on... in the garage, can't check tonight).
______________________________________________________________

Andy Wehmeyer :
Calibrate the system while the car is stationary. Then, use the 31-band EQ to make adjustments that mask the road noise. There's no need for different crossover points, time alignment or channel gain with the top up or down or the car moving. That's what the 31-band EQ is for
______________________________________________________________


----------



## Tendean17

*Happy Customer
*
Npdang :
Conclusion: Big thumbs up to JBL. For most people, after learning some of the quirks of the device (gains, tuning limitations) I think would be very happy with it. So far it is the best auto-tuning processor I've heard and is relatively straightforward and easy to use. If you're a picky/expert tuner, and you already have a setup that has been tweaked to perfection there is really no reason to buy the ms-8 unless you want to try logic-7.
______________________________________________________________

TheHatedGuy :
dunno...my MS-8 setup sounds pretty good- I did get a 2nd and 3rd at IASCA Finals years back. And I have owned an ODR and F#1 setup.
But like I said, it is ok without the center...but adding the center takes the system up several notches.
But what are you exacly expecting out of primarly a stock system? I ran mine on mostly stock speakers, but better speakers do sound better.
______________________________________________________________

Bikinpunk :
If you love car audio but really hate tuning or just don't know how, then this processor is for you. The MS-8 does in 5 minutes what would take me a couple months of hard work to do. Then throw in the added benefits of great sound at different seats and I've just added many more months onto my manual tune. 
______________________________________________________________

Thebetaproject :
_Just wondering, where has the MS-8 placed the centre of the soundstage? Thx, in advance.
_
Bikinpunk :
in the acoustic center... which happens to be on the center of my dash.
______________________________________________________________

Dwaynecherokee : 
_I just had a demo of Erin's car early today and I concur that with just the auto tune, his car sounds better than it did with his manual tune from the bit one. I don't say that to knock what he had done, or to say the MS-8 > Bit One, bit his car does sound better imo and he knows I have the golden ears 
The sound is definitely centered on the dash and remains that way if you move your head around. What I thought was weird was when we toggled Logic 7 off and on while demoing tracks. Imo you definitely can tell a difference when it is on or off. He doesn't have a center channel so maybe that's the issue, but I thought when Logic 7 was on, it seemed attenuated? I literally closed my eyes and he switched it back and forth and I could tell each time. When I listened to Erin's car about a month ago, I felt it lacked a little "oomph" in the mid bass to sub bass areas. Just off the auto tune on the MS-8 it definitely fixed that flaw that I felt he had. We played a few tracks that I KNOW what they should sound like, and they were much better this time around.

As a recent bit one buyer, I'll admit I was this || close to pre-ordering the MS-8. It is definitely an impressive product and seeing improvements in someone's car certainly makes me want to reconsider, but at the end of the day, I honestly think you can make your vehicle sound good no matter what processor you choose. The advantage with the MS-8 is that it saves you time. 

The P99/P01 is still awesome. The Bit One.1 is still awesome. 6 months from now when Company X releases Processor X, the MS-8 will still be awesome. At the end of the day, I don't think either one of those is > than the other. It's all about what you are trying do with your system and how you want to accomplish that. Nonetheless, Erin's car sounds great and I really like it better this time around. The MS-8 is an amazing product.
_
Bikinpunk :
Thanks for throwing in your $.02, Curtis.
______________________________________________________________

BigRed :
Got mine installed just a little while ago.
Front 3 way with center and rears.
UN FUK N BE LEAVE A BULL!!
It did what took 2 years to do in tuning less than 5 minutes. the center is locked in and the rears add an ambiance that you will never achieve with 2 channel in my opinion.

I used an electronic crossover between mid/tweet to allow full active 3 way up front. I even used the 80hz crossover on my subs just to see if I could prove Andy wrong on this subject. I lost. The sub to midbass integration is perfect, with no hint of subs behind me. This thing is scary good. Props to JBL. It was a cinch to set up.

And you don't need no stinkin optical!! Its as clean as can be in analog! 
Lovin it big time!!

Channel 1/2 = midbass
Channel 3/4 = mid / tweet (output fed thru electonic crossover splitting signals)
Channel 5/6 = rears
Channel 7 = center
Channel 8 = sub

hope that helps 
______________________________________________________________

Se7en :
I've been experimenting with L7 on and off in my stereo 3 way and have noticed some interesting effects.

L7 off: the system sounds tonally a little flatter to me, mid and upper frequencies feel a bit dryer but more stable. The sound stage although very good, feels a touch less localized to the center. The most noticeable downside is that midbass localizes to it's respective side a bit more but it's not terrible.

L7 On: The overall tonal balance feels a bit "tipped up" in the trebble, but center stage becomes more focused and midbass locks into center stage. Downside: I can also hear some processing and the effect is pretty odd. Most noticeable in female vocals, I can hear almost a "fluttering" effect in the upper mid range and trebble. I suspect that this would not be as noticeable if I was running a center channel but the net effect is that it's almost as if the center vocal is destabilizing a bit, kind of like a flickering light bulb...

SouthSyde,

Car looks great!!!


----------



## Tendean17

*Feature Request to MS-8
*
Gutz :
_So , After installing my MS-8 and having tons of fun with it
I decided to open a feature request thread
This is based on other's request found on the original MS-8 thread and on my own

You are welcome to add and hopefully Andy and JBL team will consider our requests and implement them

1.Export & Import Settings
So we could save a setup that we loved before trying to change something in the system

2.Channel assigment Seperated From Crossover Settings
So you wouldn't have to go through all of the assigment everytime you want to check a different crossover point

3.Different Order On Channel Assignment
Instead of all of the left channels than the right channels , I think it would be best to set the order based on fr , For me at least
For example : 1.Left Low , 2.Right Low , 3.Left Mid , 4.Right Mid...

4.View Crossover Points
So we can see what are we crossing at

5.Change One setting in Channel Assignment / Crossover
Corresponding to no. 3 and 4
I would love to have the option to change only one setting in the crossover instead of going through all of the proccess all over again
So something like a menu with the current crossover point and the ability to change it at will would be great

6.L7 Off By Default Without Center/Rears/Sides
In the present , Even if you don't set center/rears/sides
L7 will be on when the calibration is over
I think it should be set to Off on default with this kind of setup

7.Run Calibration To A Specified Position
If I'm testing a crossover setting and re-calibrating 
I'm usually only calibrating to my seat
I want to be able to continue from there to the other positions if I like the setup without calibrating once again from my seat

8.Screen-Saver
Even the startup JBL logo will be enough for me when I haven't be using the screen for 1-2 mintues
I just hate to see a menu all the time

That's it for now I think , Please Add your requests
Thanks To ANDY and JBL team for paying attention to user needs

_Andy Wehmeyer :
I'll try to address all of these:

1. We're working on the firmware update software and have talked about some way to save a setup before updating and reapply a setup after updating. This may be the same thing.

2. This isn't going to happen because the code is written so that MS-8 builds the system as a serial process and throws away "old" information as the new information is entered. 

3. Are you asking that the possible "locations" (Left Front Low, Left Front Mid, Left Front High, for example) appear in a different order? I don't understand why that makes a difference. It seems arbitraty to me and a simple matter of preference. If you don't want to scroll through the menu and have to back up, then connect the speakers or amps in the order in which the channels appear in the menu. I could NEVER get engineering to spend a week rewriting this. 

4. View crossover points when? After setup? As a separate menu? So you can re-adjust them later if you run setup again? You'll still have to write them down because when you enter setup, those filters are erased. 

5. Ain't gonna happen. The crossover point that you choose is the starting point for the entire auto calibration. This is differnt than a standard practice with manual tuning. After you enter the crossover, the EQ adjusts the frequency response based on measured acoustic response. If you move the crossover, the acoustic response changes and the EQ would be "invalidated". The point is that tuning with crossovers is a bad practice. Crossovers should be set for driver safety and to keep drivers playing within their piston range (where dispersion is wide). EQ is for tuning. 

6. I agree. This was an oversight. I'll put it on the list of possible changes.

7. Unfortunately, this isn't posisble. MS-8 doesn't save measurements, it saves correction filters. There isn't enough memory to save all the measurements, which is what would be required to allow the unit to run the optimization and then re-enter the calibration phase of setup. 

8. This was in the original spec, but we deleted it to make room for something else. I'll also add this to the wish list


----------



## Tendean17

DS-21 :
_I would like a polarity/"phase" check (as Audyssey MultEQ XT offers) for all channels contemporaneous with the first chirp (could be a separate thing, but contemporaneous is what Audyssey does). Just a warning to check with a click-through. Like Audyssey. It wouldn't matter, except for the effects AW has written that out-of-polarity drivers could have on calibration efficacy.

And, I know Andy hates the idea, but the possibility (maybe even with a "THIS IS A BAD IDEA! DON'T DO IT!!" click-through screen) of overlapping at least midbasses and subwoofers. In a car, where it's entirely possible that someone might have more volume displacement on the midbasses than the subs (as a general rule bad design practice, yes, but in a car you work with the space you have) and may wish all of those drivers to contribute down low.
_
Andy Wehmeyer :
1. Originally, this was part of the spec. We can check polarity for all speakers reliably except for tweeters. Since we couldn't do them all reliably, we eliminated the feature. We provide wiring diagrams for most cars on line, which should make it easy to figure out what's + and -. 

2. No way. Having all speakers contribute down low doesn't work. I used to think it did and that it was a good idea, but after fixing Eldridge's car at finals one year and trying this in my own car for years, I'm convinced and there's no going back. The idea with MS-8 is to give you tools you can be successful with, not to give you a box of tools. Yes, call me a big government progressive, if you must, but I only have so much time for tech support calls. BassQ is unnecessray in cars and at frequencies where it might be beneficial from a "uniform coverage" standpoint, the delay, level and EQ adjustments don't preserve imaging. THat works at low frequencies because we have a much harder time determining the origin of the sound. Plenty of experimentation have proven this in our own labs.
______________________________________________________________

Thehatedguy :
_Yeah I wouldn't mind being able to bypass the subsonic.
_
Andy Wehmeyer :
Set it at 20Hz, 1st order
______________________________________________________________

Andy Wehmeyer :
OK. Here's the scoop :

1. The MS-8 includes a DSP (TI 610xx built specifically for Harman). That IC is in the amp. It also includes a microcontroller and a display driver. Those are included in the screen. The screen is NOT a video screen and there's no opportunity for a composite video out. The remote is RF and the receiver is in the screen. The display sends control strings from the micro to the DSP. 

2. The design of MS-8 was completed before there was an iPhone. 

3. The iPhone is not RF, but a dongle can be used to turn it into an RF remote. There's no easy opportunity to communicate bi-directionally with an iPhone or Android phone, which would be required to place the UI on a remote device. 

4. MS-8 is our software platform on which other products will be based. We'll incorporate phone features into future products (we're not blind or stupid) 

From my perspective, all phone GUIs are inappropriate for use while driving. Any good integration of smartphones and their capabilities for cars should make your favorite apps and features available in a driving-friendly manner. This is a big job, but we're a big company. Stay tuned. 

The second of the autotune products will be available soon. It's not a higher-end MS-8. Rather, it's a very simple device designed to dramatically improve the sound of your car (or maybe your wife's car) when you (or she) listens to a portable without any installation hassles. It can be moved from car to car, used at home or with any system with a 3.5mm input and takes less than a minute to set up. Production begins in two weeks and I've approved final firmware yesterday
______________________________________________________________

cajunner : 
_until someone develops a touch screen where you can draw your curve, and have the processor "make it happen", and calibrated mic analysis inside the vehicle at the processor mic's identical position shows that you will, indeed, have that curve, I think there's going to be some room for improvement...
_
Andy Wehmeyer :
this would be a kickbutt option, I think. Pen stylus, nice 20-20k side scrolling graph, and a bank, and corresponding book of preset curves that have been "celebrity" advertised...
This is, essentially, what MS-8 will give you. Instead of a pen and stylus, you get 31 bands to draw your curve once the correction curve has been applied.


----------



## Tendean17

Thanks for reading ... and Hopefully useful.


----------



## Salami

Tendean17 said:


> Reserved ..  60
> 
> The last post.
> 
> Under Construction !! Please don’t post a replay or comment this thread until I finished it.. I make very long post here. I’ll make some update and correction here.
> Thanks.


Hope you type quick. You only have about 21 hours before you can't edit your posts.


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## masswork

Hope i'm not mistaken 

Nice to see you here Mr Tendean17


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## Tendean17

Salami said:


> Hope you type quick. You only have about 21 hours before you can't edit your posts.


You make me scared .. cause i don't know about these rules .. but finally I could finish it at 3 AM in my local time.



masswork said:


> Hope i'm not mistaken
> Nice to see you here Mr Tendean17


Yes .. it's me.


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## nineball

excellent thread mate. job well done.


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## 14642

Awesome. Thanks a bunch.


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## thehatedguy

Don't forget...

The larger your center is the more you will enjoy the MS-8.

Do not skimp on the center. It should be every bit as good, or even better than the sides.


----------



## SIDEWAYZ

My remote stops working intermittedly.. I can usually shut the car off then back on and it fixes the problem but now that wont fix it. The system was installed only 1 week ago. It shouldnt be a battery problem in remote. Any ideas? Please....If I push reset on main controller will that wipe all my settings out? I understand there may be a cable problem from the processor to the controller? Thanks


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## Tendean17

*Re: JBL MS-8 FAQ - I added some links and articles*

I added some links and articles cause as Salami said, i can't edit my post anymore cause i'm regular member.
You can always go to the original thread if you thing something missing about my post and i already give you the list of links.

*MS-8 Thread Links :*

http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/85018-ms-8-center-channel-speaker.html

http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/91764-measurements-what-ms8-doing-my-car.html

http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/82601-best-source-jbl-ms-8-a.html

Other Topics (that i like) :

http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/51115-proper-time-alignment.html

http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/92336-up-front-bass-just-illusion.html

http://www.diymobileaudio.com/forum/general-car-audio-discussion-no-question-dumb/88083-do-all-competently-designed-level-matched-amps-head-units-sound-same.html

http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/82067-diy-reducing-speaker-beaming.html


----------



## Tendean17

*About JBL MS-8*

lycan :
MS8 accepts "balanced" signals (thank you Andy!), which means it does a good job of "differential noise canceling" on the analog inputs (whether they are impedance-balanced, or not). Furthermore, anyone interested in MP3's and Ipod's and all that other stuff is more concerned about convenience than the "utmost" in fidelity anyway so you'll want user-friendly, easily-accessed volume control. Conclusion : use whatever analog-output source you like, and call it a day 

(only joking about that convenience crack ... or was i? ) 

TheHatedGuy :
Just a FYI, "lycan" as he goes by on the forum was Senior VP of R&D at Crystal Semiconductor and part of the team that developed the first multibit DAC. If there is one person in the world, much less this forum who knows about digital audio...my guess it would be that man. I would really take heed as to what he is saying. 
__________________________________________________ ____________

lycan :
_yeah ... but you think Jessica Rabbit is hot._

Andy Wehmeyer :

Yes, she is hot.

The last time I competed in an IASCA/MECA show a couple of the judges told me, "Man, that's incredible. I've never heard a car reproduce the ambience and the sound of the room as accurately as your car does."

I said, "Thanks", but I couldn't bring myself to tell them that none of those sounds were actually in the recording and that they were generated by my DSP. 

I love music--almost all kinds--and refuse to constrain my ability to enjoy it to the few times I listen to really great recordings. The fact is that in many cases, the artists are the ones who insist on mountains of dynamic range compression because they can't abide the thought that someone else's recording will sound louder when a listener hears it on some tabletop system with woofers the size of quarters on on a 99-cent pair of earbuds. Or they say, "We want that '70s sound", (which means no bass and sounds panned hard left and hard right). 

The fact is that I am an audophile and am not well served by recording engineers. If I have to dramatically change the sound to have an experience worthy of the amount of time and money I've spent on my system when I listen to popular music, then so be it. Unlike some others, I can tolerate HUGE errors in frequency response so long as spatial qualities are good. What spatial cues exist in a Black Eyed Peas recording? None. So what's fun about listening to that stuff? Dre has the frequency response thing down. Listen to any hit that he's ever recorded and run a frequency response measurement on the duration of the track. They're all similar and they sound great--so long as one doesn't care about the "room". I care about the room so I have to create one or it isn't fun enough to satisfy me. 

I think the point is that the artist intends the "event" to be engaging, but sometimes he doesn't know what that means in terms of audio reproduction for different kinds of listeners. Here's an example:

I once had a conversation with a VERY well-known and VERY successful record producer who told me, "Man, most audio companies just don't get it. You guys always talk about flat response and accuracy. We want you to reproduce what we experience in the studio, and that experience can't be put on a disc. These guys mix records on an $800,000 system that plays crazy loud with tons of really tight bass. Reproducing that experience is your job--we can't put that on a disc. That's why we're making gear. Why am I telling you this? Because you seem to get it." 

When I demo'ed their tracks for them in the car we were demonstrating, they wanted to know why it sounded "mono" when the DSP was off. I said, because that's what's on the disc and the inside of a car decreases the "stereo" effect anyway". When I turned the DSP on, they said, "Wow. That's what it's supposed to sound like, but it needs more bass." 

Making recordings sound different doesn't have to be smoke and mirrors and a bunch of techno-babble. We can, in fact, figure out what we need to do to playback systems to make the experience more engaging and if the audio industry is to survive, we have to do it.


----------



## Tendean17

*Center and Rear Channel*

Andy Wehmeyer :
I prefer a big speaker pointed up at the windshield, but what do I know?


Andy Wehmeyer said:


> ^^^Kinda jerky, but true.
> 
> This on and off axis thing is about as misunderstood as any audio topic (besides the high-end wire BS). I'm posting this polar graph again--maybe I should just add it as my signature.
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> The top graph is the polar response to which Mark is referring. It shows output level at various angles off axis for a few frequencies. Beaming at high frequencies is apparent, but this idea that you can use a speaker in a car in a range where it beams effectively is BS, unless you're building a system in a school bus. This is for an 8" woofer, but essentially the same pattern exists for all round drivers. For a smaller driver, the frequency where dispersion begins to narrow would be higher. In order to use a simple round speaker for pattern control, this 8" would have to be high-passed at about 1k. So, it's a really inefficient 8" tweeter that doesn't play high frequencies very well. Perfect.
> 
> The second graph is the same speaker plotted as a frequency response graph measured at various angles off axis.
> 
> It's pretty esay to surmise that used in a range where the 8" is designed to operate most efficiently (below 1k), the radiation (dispersion) is pretty uniform into most forward angles. That means that no matter which way you point the speaker, the response is "on axis", but there will be a little bit of attenuation at high frequencies. So, if I point the speaker up at the windshield, I can mount it in the dash (so long as there's room) in a way that looks nice and I can put a tweeter next to it. There's going to be a giant collection of comb filters because there will be a reflection at all the forward angles off of the *slanted* windshield. There's no way to control this other than to use the entire windshield as the mouth of a horn, but trying to build that as more than a big crapshoot is too much work for relatively little benefit and the big horn will have its own share of frequency response problems. The good news is that the combination of the combs is mostly hard to hear and you can fix it adequately with a couple of low-Q filters. MS-8 will do this for you.
> 
> Here's the polar response of a 1.5" tweeter:
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> It's pretty easy to see that the dispersion is wide for most of the useable range except at the very highest frequencies.
> 
> The graph below is what happens if I use a big mid and a little tweeter. The black curve is off axis and the red curve is on axis.
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> Since our speaker (no matter whether it's a center channel or mounted in the door or kick panel) will radiate much of its response uniformly into most forward angles, we'll hear the on-axis and off axis responses combined. The off axis response will be reflected off of nearby surfaces and the on-axis response won't. If you mount the speaker off axis, then the off axis response will have a direct path to your ears and the on axis response will be reflected. In any case, you'll hear the combination and the combination of the two graphs leaves a hole at the crossover point. Pattern control is out the window because of all the boundaries--those adjacent to the speaker, those adjacent to your ears (which will reflect the same response that your ears hear) and all of those in between.
> 
> For the center channel pointed at the windshield,there's going to be a hole, but the windshield is relatively flat and will reflect whatever is pointed at it in a pretty uniform way. If on-axis response of the speaker is similar to the off axis response of the speaker, then the reflection will be similar to the response you hear directly from the speaker. Since the arrival times will be close enough that you won't hear them as separate events, the _apparent_ source will be in between the source and the reflection, whicis higher than the dash and raises the stage. This will provide a nice, big center image.
> 
> Of course, you'll have to deal with the suckout, but that will happen no matter whether you mount the speaker on or off axis. That's what EQ is for and a low Q suckout is easier to fix than a high-Q suckout. You can't EQ the on-axis and off axis responses separately.
> 
> The moral of the story here is that if you're not building some big-ass horn, using waveguides of some sort, using carefully arranged driver arrays and serious DSP or using 15" drivers as midrange and 8" drivers as tweeters, there's no effective pattern control in cars and you're better off using speakers where they're intended to be used (within their piston range). No matter what you think is happening or what some IASCA mofo wants to pitch in the interest of additional complexity for a few thousand more "upgrade points" or to sell some BS speaker, speakers aren't flashlights, they're floodlights.
> 
> The benefit of the "wideband" 2" tweeter is that it can be crossed low enough to match the woofer at a frequency where the woofer's dispersion is wide (low directivity). However, dispersion fro the 2" is bound by the same law as all other speakers (no matter the cone material or the marketing spin), so the same thing I've illustrated here with the 8" holds for the 2", but at much higher frequencies. There isn't a lot going on at 15k, so it probably doesn't matter.
> 
> The simplest and best sounding system is a 3-way (with a 3" mid) mounted in the door and a center channel pointed at the dash, IMO.


Oops. Yes, I meant windshield. Center channels for MS-8 should include a tweeter and should be the largest mid that you can get in there. 

I should also add that this is the best sounding MS-8 system. In order for a system that includes a center channel to work properly, there has to be some way of extracting the center. L+R is not a center. 
__________________________________________________ ____________

TheHatedGuy :
As big as you can get. And on axis as much as possible.
->
Hmm, redoing my center channel now...on axis or up at the glass?
Maybe some of both?
->
I had the last one sort of angled up at the dome light...which was what I was thinking as sort of "both"
->
One of these days I might add some 3 or 4" midranges to the kicks with the 6s...but right now I am pretty pleased with the sound.
__________________________________________________ ____________

MarkZ : 
_Care to reveal how center is computed with the MS8, or is this proprietary?_ 

lycan :
i can't answer ... but for the casual reader, here's why that's an interesting question. To a crude first order, the "center" is the signal (or info) that's common to both left & right channels. We can express the Left and Right channels that stereo provides as :

L = Lt + C
R = Rt + C

Where L, R are the familiar stereo channels; Lt, Rt are "true" Left & Right; and C is the common center signal.

Sadly, there's no simple algebra that can "isolate" C from L and R (the classic approximation of L + R doesn't really do it cuz you've still got Lt and Rt in that simple mix). That's why ProLogicII, Logic7, Neo:6 use proprietary algorithms to "extract" a true center from L, R. 
__________________________________________________ ____________

mitchyz250f :
_Andy, still not completely clear. Does the MS8 work better, with a 3-way, with the mids mounted in the doors instead of the kicks? _

Andy Wehmeyer :
No, MS-8 will work with either. Doors will give you a wider stage, so long as you have a center.
__________________________________________________ ____________

wadejg :
_Andy, since you recommend a tweeter for the center channel one starts running out of channels for the MS8 to control, unless you use a passive crossover for the center.
If I run my front left and right active/biamped, that uses 4 channels, 1 sub channel, 2 rear channels, which only leaves 1 channel for the center. Would you skip the rear channels with an active 2 way center or run the center passive and keep the rear channels.
I'm trying to figure out how, assuming 1 channel used for a sub, you would use the other 7 channels left.
Thanks, Justin_

mattyjman :
you have two options... passive for center, or use active controls on your amps for the center.... that's what i will be doing, as the ID amps have bandpassable controls for the center... if the tweet and mid on the center are close, there is no reason why you would need two channels for that... so a passive or separate active crossover should be fine...
someone correct me if i'm wrong here

Andy Wehmeyer :
you're right. I'd just use a cap on the tweeter and bridge the two chanels to the center.
__________________________________________________ ____________

BigRed :
my experience with the MS-8 is this....don't overcomplicate the center...put the biggest driver you can that plays full range (mid /tweet, coaxial) and call it a day. the lower you can cross it over and match your L/R, the better

TheHatedGuy :
agree. Right now my center is the same as the fronts and crossed over at the same points. But for fun the other night, I highpassed the fronts at 80 and the center at 50


----------



## SIDEWAYZ

I got my remote problem fixed. Now the ms-8 sounds like crap when I'm running off the factory head unit. I have 2-10's in the rear being pushed by 1 amp, 2-6x9's in rear deck pushed by Jl audio single amp and 2-6x9's in door on 1 jl audio amp. When I play the ms-8 through the stereo on either car fm, cd or satellite, it sounds like CRAP. When I play it off my iphone it sounds great. Its like I lose my bass going through the head unit. Any ideas?? Its so frustrating. Please help


----------



## donkeypunch22

Awesome. Thanks OP!


----------



## jaceves

Andy,
I have a 2011 Hyundai Sonata 4dr with Factory Navigation and 7 speaker system (consists of a front 4”, rear/back 6.5” and 8” factory sub). No additional amps.
Replaced factory speakers with the following:
•	Front Dash now: 4” Infinity 32.9FC (Freq Rsp. 85hz – 25k)
•	Front Door now: 6.5” Infinity 63.9i (Freq Rsp. 45hz – 30k)
•	Rear Door now: 6.5” Infinity 63.9i (Freq Rsp. 45hz – 30k)
•	Factory 8” factory sub remains 
I have been struggling to determine how to setup the basic configuration of this system. I’ve attempted to contact JBL technical support but they have been of very little help other than to tell me to use the default settings. 
Questions:
•	Should I run the dash and front door speakers as 2-way or as 1-ways?
•	What are the recommended cross over frequencies and slope based on my setup?
•	Lots of echo with the BT phone. Any idea how to correct?
•	I have my single 8” (infinite baffle) Factory sub bridged off channels 7 & 8. During the setup, do I set up for two subs? 
I tried to make this email as concise as possible and I apologize in advance if I am logging this into the wrong forum. Any help you can provide would be very much appreciated.


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## nineball

this isn't a question thread. if you have questions you should post them in the correct thread in the sq section.


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## Neil_J

MS-8 Input Calibration CD info from Andy


Andy Wehmeyer said:


> So, when MS-8 runs input calibration, here's what happens:
> 
> The signal on the CD isn't random pink noise. It's a very specific signal designed to allow MS-8 to understand precisely what happens in the factory system in both time and frequency. It's also different in right and left, which allows MS-8 to determine whether a channel is left, right, or mono.
> 
> "Input Low" means that there isn't enough level for MS-8 to do what it needs to do and maintain acceptable resolution of the signal, once it's converted to digital. In other words, "Turn up the volume". IF you've turned the volume of your radio all the way up and MS-8 still reads "low", then you need a line amp or you should use the radios's speaker level outputs.
> 
> "Input High" means that the voltage of the radio's output signal is too high and will cause significant clipping of MS-8's input--too much for MS-8 to assure low distortion performance. "Turn the volume down" or "attenuate the output of the radio some other way" is what that means.
> 
> "Input None" means that MS-8 does not see the signal that's on the disc modified in a linear way in either time or frequency. If the signal is not sampled at 44.1k, + or - about 0.5%, this will also cause a "Signal None" condition. We'be built sample rate correction into the algorithm and that's what allows the + or - 0.5%. This is a significant accomplishment and one that isn't included in other products of this type. In order for MS-8 to analyze the signal in the time domain, there has to be a baseline, and 44.1k as the sampling rate is the basline.
> 
> "Signal Noisy" means that the signal is recognized but that it's so heavily clipped that MS-8 can't use it.
> 
> The reason that shorted inputs would cause a "Signal None" condition is because MS-8's first "question" is, "Is there anything on the input?" A short is a "Something". Then, the next question is "Is the 'something' similar to what's on the CD?"
> 
> There's another condition that has been reported a couple of times, and that's a condition in which MS-8 reads "Signal Low" until the volume control of the head unit is increased to a certain point at which MS-8 reads "Signal None". This indicates that there is something non-linear ,that isn't clipping, that happens to the signal at that point. I haven't had an oppotunity to do any investigation, but this has happened in two Audis with the B&O DSP system.
> 
> Once MS-8 reads "OK OK OK", that means that it recognizes the signal, that it's loud enough but not too loud and that the level between left and right is the same, within a couple of decibels. Then, when you give it the command, it measures the relative delay of the signal on each channel, lines up the initial inpulses (and uses another sneaky trick to accurately measure the delay of low passed signals), combines left channels, combines right channels, applies a 200Hz low pass filter and an all pass filter to the mono channels so they'll sum with right and left without phase errors. Then, MS-8 applies the same kind of EQ to the input signals that it uses during acoustic calibration.
> 
> The way EQ is accomplished is another MUCH more complicated explanation.


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## Neil_J

Andy on the "Andy Curve" aka why is my midbass gone? (emphasis mine)


Andy Wehmeyer said:


> So the reason for the three way is to avoid using the midbass (6") in a region where, a) the on-axis response is rolling off, b) where the peak in the response from the major cone distortion mode doesn't roll off as fast as the rest of the response, 3) where the dispersion of the midbass narrows.
> 
> If you use a 2-way, you have to cross the tweeter low enough to meet the midbass, c.3500Hz. You can ONLY use the much higher crossover on the tweeter if you have a small midrange to bridge the gap.
> 
> So, you can pick and choose the "rules" you want to follow, but it doesn't make any sense to follow three of them, blow off the others and then come back and post, "In my experience, Andy's suggestions don't work.
> 
> I do suggest keeping the little mids OUT of the dash and out of the A-Pillars. A-pillars do one thing well--they raise the image. If that's the most important thing to you, then go for it. However, width will suffer. Image size will suffer.
> 
> Since "performance" is subjective, some of you will prefer all kinds of other stuff--see the whole midbass thing. *MS-8 tunes basically flat from 160 Hz to 1kHz. For those of you who compete in MECA or who LOVE the sound of your Beats headphones (I like Beats headphones, but not because of the bass, but because of their creative use of multiband compression), you'll want to use the 31-band EQ to boost between 100Hz and 500Hz. MS-8 is not designed to make the 6x9s in your doors move your pant legs. It's designed to place the image of the bass in the front and to allow you to boost the bass with the sub control without changing the apparent location of the bass. Why? Because I like that, because I spec'ed it and because I've made a majority of my customers happy with that for 25 years. This, however, did not make judges happy. They like big, fat midbass. I don't like big fat midbass because when I hear that, I hear much poorer definition in vocals, piano, the lower ranges of all string instruments and the percussive parts of those string instrument sounds. *In my experience, that kick-your-ass midbass happens at live shows when the system is loud and the midrange is flat, but it doesn't happen at lower volumes. At lower volumes, the snap of the sound of someone whacking the string of the bass guitar with the side of his thumb sounds percussive, and that's what MS-8 is designed to preserve. If what you hear or what you like is different, no problem. This is why there's an additional EQ that you can adjust.


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## Neil_J

Andy Wehmeyer said:


> I used to cook this pretty cool chicken thing when family came over for the holidays. One of my relatives asked me for the recipe. Of course, it included a bunch of butter, cream, shallots, etc. The recipe was super simple. A few weeks later, I got a call..."Are you sure you gave me the right recipe? Mine didn't turn out so well."
> 
> "Why?" I asked. "Did you follow the recipe?"
> 
> "Yes, but I made some substitutions because I don't like all that fat and shallots were too expensive."
> 
> "Hmmm..You liked it when I cooked it." I replied. "What did you use instead?"
> 
> "For the shallots, I substituted garlic powder. For the cream, I substituted skim milk, and for the butter, I used olive oil because it's much healthier. I don't think your recipe works very well."
> 
> "Well, MY recipe works fine. It sounds like your recipe didn't work very well," I countered. "To avoid confusion, maybe we should use different names for our versions of the dish. Why don't you choose one and then I'll choose something else."


I find this story about chicken very relevant  We have been given many great MS-8 recipes by Andy. Many are in this FAQ. Follow the recipe(s) unless you fully understand what you are changing, and what the effects will be.


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## Tendean17

*Update 28 Nov 2011.*

After 8 months .. there are more information that i collect.
Some are from old thread that i miss them from my previous post ...
Some are very usefull post from all my masters ... related to MS-8 and some are the best posts for preparation and design ...
Maybe someone need these (including myself … for reference).
All in this thread are select and copy from almost 50 best threads count from the 1st page.. 
You can always go to the original thread if you thing something missing about my post.

(Open Google or other search engine -> Type “diymobileaudio” follow by about 4 words from this post -> it will show you the original post -> Sometimes much easier than using Search Button).

*MS-8 Thread Links ( and Others Topics ) :*

http://www.diymobileaudio.com/forum...al-advanced/117783-where-does-width-come.html

Image Width - CARSOUND.COM Forum

http://www.diymobileaudio.com/forum...tional-crossover-points-any-explanations.html

http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/117041-jbl-ms-8-review.html

http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/75276-imaging-woofer-door.html

http://www.diymobileaudio.com/forum...121-best-way-get-proper-imaging-midrange.html

http://www.diymobileaudio.com/forum...d/100439-ta-measuring-off-axis-woofers-4.html

http://www.diymobileaudio.com/forum.../94854-questions-about-crossover-phasing.html

http://www.diymobileaudio.com/forum...ed/94839-passive-x-over-info.html#post1190206

http://www.diymobileaudio.com/forum/diyma-sq-forum-technical-advanced/62160-new-myth-truth.html

http://www.diymobileaudio.com/forum...7-why-everyone-using-active-crossovers-4.html

http://www.diymobileaudio.com/forum...uning-question-andy-w-anyone-wants-chime.html

http://www.diymobileaudio.com/forum...ng-gains-minimum-ultimate-sq.html#post1123737

http://www.diymobileaudio.com/forum...-test-prove-whether-testing-ear-any-good.html

http://www.diymobileaudio.com/forum...vanced/57747-dash-mounted-center-channel.html


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## Tendean17

*About JBL MS-8 *

Andy Wehmeyer :
MS-8 is designed to provide the impression that the bass comes from the front. If that's what you heard, then it did it's job. From your post, it sounds like it did it's job well enough to fool you. 

If you want your mids to make mre midbass simply because you want your mids to make more midbass, then that's what the 31-band EQ is for...or, you can move the crossover down, which will cause your front speakers to move more--that may not necessarily sound better, though.

If you don't care about the illusion of bass up front and you just want a bunch of midbass and don't care about the placement of midbass sounds in your stage, then boost the midbass in the 31-band EQ (as you've done) and turn up the input sensitivity on your sub amp. 

Getting the illusion of bass up front requires a precise EQ and a particular EQ curve. that's MS-8's target. Fortunately for those of you who prefer a different target, MS-8 has a cool tool to allow you get what you want--the 31-band EQ.
__________________________________________________ ____________

Andy Wehmeyer :
So here's the deal--The target curve includes 9dB more bass than midrange, and the high frequencies roll off a bit--20k is -6dB when compared to 1k. 

If you're building a system and you're using regular car audio speakers and a sub, then all of this sensitivity matching isn't all that necessary, considering the amplifier power that you're likely to use. That's why I say set the input sensitivity to 2V. 

If you're building a system with drivers of wildly varying sensitivity and are using monster amounts of power on part of your system and not on the others, then you'll have to do a little work to get within the 40-or-so-dB window that MS-8 uses for EQ. MS-8 tries to level match using several analysis bands before it applies EQ. It checks the bass between 50 and 80Hz. If you cross your sub over at 40Hz and it's a 15" in a .5 cubic foot box, you're going to have problems. MS-8 sweeps a wider band of frequencies than what you choose as a crossover--it has to. 

In the example above, the woofer will have MUCH greater output above 40Hz than below. When MS-8 sweeps, it will set the bass level according to the 50-80Hz output, then it will try to EQ the bass back in. Is this bad algorithm design? I don't think so. Crossing a sub over at 40 Hz is ridiculous, unless you've designed the box above. In that case, the problem isn't that MS-8 is bad, the problem is that the subwoofer design seriously unconventional--you'd be using the sub only in the "stop-band". For a sub designed this way, the only valid reason to do it is because you have no space for woofers and have plenty of money to throw away on a seriously inefficient design. A 10" the same box would probably be a better choice. 

If you use horns and compression drivers because you're into pattern control, then you'll have to deal with the fact that they're proably 20dB more effficient than the [email protected],1M midbass that are likely to go along with them--and the fact that frequencies above 10k are likely to be almost missing. If you apply 100W to the horns and 100W to the midbass, then you're going to chew up EQ and gain matching just to get the horns and midbass to similar levels. 

So...the moral of the story here is...

MS-8 was designed to make it very easy to get a great sounding system if you build a system in a pretty conventional way. We've included lots of "edge cases", too. There are 48 possible speaker systems supported and in order for it to do it's thing, the output of the speakers needs to be within about 30dB. If you use readily available car audio gear and don't include a monster sub system, then the 2V suggestion works great, so long as the sweeps are at the right level. The window is big--turn the volume down. If you've built a system that includes drivers and amps that make the acoustic output of the various bands well outside this window, then you'll need to make some adjustments. 

If you're using a conventional signal processor, then you'll be able to more easily get things in order with an unconventional system before doing any equalizing. MS-8 doesn't pass signal until you run setup, so it's helpful to ballpark the settings the first time, but before insisting that my suggestion can't work, you might using it as a baseline. 

This saturation problem isn't unique to MS-8, it's just better hidden with regular RTAs. When you saturate the input (mic or preamp) of a regular RTA, the data you view gets compressed and the curve looks nicer when you make frequency response measurements. This is a convenient little lie and one that few novice tuners are likely to question. However, in my experience this is a contributing factor in the "flat response don't sound no good" view. 

If you try to set time alignment by making impulse response measurements and you saturate the input, you won't be able to accurately pick the peak--and MS-8 can't either. The difference is that with the manual method, you'll be able to enter the wrong number or make a measurement with a ruler and enter that number and move on. In this case, MS-8 just doesn't set the value or doesn't EQ. Is that worse? Hmmm...depends on your view. I wish MS-8 would flash a big red light and say, through the speakers, "Dude...unconventional system detected. Please turn down the bass" (or something to that effect), but it doesn't. That's why I sit here in front of my computer typing into this forum all the time. 

Gary and I used to have to show up two days before an IASCA contest with a suitcase full of gear to tune Team JBL cars so our guys' cars would sound good. Now, Gary and I show up the day before the show eat a nice dinner, make a few adjustments with MS-8's remote and the results are usually better.

All of this boils down to one very simple statement--MS-8 uses a different method of tuning a car and has its own constraints. Once you accept them and learn to work within them, the process is simpler and will probably yield better EQ results, unless you're a master tweaker and have serious analysis tools and processing capability and the time to spend making a thousand adjustments.
__________________________________________________ ____________

BuickGN :
_I saw this question posted but I never saw a reply..... When you turn the processing to "off", crossovers are still in effect, right? I'm getting ready to run my tweeters passive next weekend but right now I have no bass blockers. I have no plans to turn processing off ever again but still curious._

Andy Wehmeyer :
Yes, crossovers remain intact.


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## Tendean17

Andy Wehmeyer :
OK, a little more information about the "case can't touch ground" iussue.

In cars, we have ground and 12V. In homes, we have hot, neutral and ground. In home electronics, the audio ground is "created" in the unit and is NOT chassis, which is ground. Inc ars, we don't have that luxury, because the potential is not across hot and neutral, it's across hot and ground. The same ground that carries the current for the charging system is also audio ground, at some point. 

Long ago (when ground loops were ALWAYS an issue), the audio ground was the shield of the RCAs on the input and the output. That's bad. Now, most amplifiers break that audio ground at the INPUT of the amp and provide the same ground for the next piece of equipment on the output. 

Ground provides the "reference" for the power supply and for the audio signal. This is a huge pain in the ass. Fortunately, nearly everyone has figured out that the low level audio signal should be isolated from ground where it can be in order to reduce the possibility of loops. 

In a big amp, you'll find that the ppower supply ground and the speaker negative are common and that this is also sometimes common to the chassis--especially if it's a class D amplifier which requires a shielded case in order not to completely destory your FM reception. Many class-D amplifiers are "mono" amps and the most economical way to make a bunch of power is to bridge two channels. On a class-D subwoofer amplifier, you won't often find a speaker output connected to ground.

The amplifiers inside MS-8 are BTL (bridged to load). This means that there's no speaker connection common to chassis on the output, because the channels of the amplifiers are bridged. You'll find that both + and - on the output are "referenced" to 6V, just like in a head unit. The RCA outputs are connected to ground, just like in any other product.

You may also notice, that MS-8 almost NEVER causes a ground loop and in cars where there is engine noise, it's often another piece of equipment that causes an incompatibility. I'f had this happen once, where the subwoofer amplifier's input RCA connections were 200 ohms away from ground and the high frequency amplifier's RCA connection was 1k ohms from ground. The RCA outputs of MS-8 are connected to ground, just like every other piece of equipment and this common connection caused the loop. This would have been the case with the combination of these two amplifiers with or without MS-8. 

The fact that the case is common to ground is no problem, unless you have a bad ground connection for the power supply OR AN AMPLIFIER CONNECTED TO THE RCA OUTPUTS OF MS-8. 

Power supply ground connections don't cause ground loopes anymore, wo when I see all of these suggestions in "I have noise" threads that indicate that one should run 0 gauge cables directly from the battery, I think, "Man, that's going to be a waste of time" and it almost always is. 

Ground loops ALWAYS happen on the signal inputs and outputs of equipment that isn't compatible. MS-8 is designed to eliminate this problem and both the speaker level and line level inputs were painstakingly designed to eliminate the possibility (or to come as close as posisble to eliminating it) without a 50-dollar DC/DC convertor to isolate chassis ground from audio ground. In the rare cases like the one above where other pieces of equipment cause a loop, install one of those RCA ground loop busters. It doesn't matter whether it eliminates bass, just re-run calibration and MS-8 will put the bass back in. 

So, if you have a ground loop in your system that includes an MS-8, look elsewhere and use a ground loop isolator. If you have a ground loop in your non-MS-8 system, don't waste a bunch of time and money on 0 gauge cables, because that isn't the problem. Measure the voltage between all of the ground terminals of the amplifiers. When youj find one that shows some potential (voltage), fix the bad ground conncetion.

If all the ground connections don't show any potential, you don't have a bad ground and the loop is on the signal lead. Use an isolator. that's the only way to fix it because the signal input's conncetion to ground that's designed into the amplifier is causeing the problem. That doesn't necessarily mean one amp is more poorly designed than the other, it just means that they don't work very well together. 

OK, now to the OP's problem
__________________________________________________ ____________

Andy Wehmeyer :
There's another question that I'm getting pretty often and that's about connecting more channels than MS-8 needs.

If you have an aftermarket radio that provides two full range channels out, that's all you need. Can you hook up more? Yes, but there's no benefit real benefit and it just makes the DSP work harder. Consider this:

If you hook up two full range channels and the subwoofer output, then you'll have the ability to control the level of the bass from the head unit. Maybe this is convenient. However, because the subwoofer signal includes a low pass filter, it will be 180-degrees out of phase with the front signal at some point in the transition band. When you run input setup, MS-8 includes an all pass filter that will put them back in phase--problem fixed...until you adjust the level of the bass. Then, the transition band changes and the phase filter is no longer valid. Is this a big problem? No, but why create even a small one? MS-8 has plenty of work to do even when things are pretty straightforward. MS-8's subwoofer control sounds much better than doing it this way, anyway.

In an OE system, which is what the UN-EQ was designed to fix, the subwoofer level is never adjusted in this way. All of the frequency conrols are EQ rather than levels for separate crossover bands. 

If you have an OE system with 6" speakers or larger in the doors, don't even bother hooking up the output of the subwoofer amp to MS-8. MS-8 has enough EQ to put the bass back in if the crossovers in the front are anywhere close to 100Hz. IN some cars, the fronts have NO high pass filter and the sub is just there for additional bottom end. This is really bad system design and creates all sorts of phase errors (one of the reasons that none of us like our OE systems very much). 

This is a little like making a sandwich for someone who tells you, "Please...just two pieces of bread, some mustard and one slice of ham". So instead, just to make sure you get everything, you put on 10 slices of ham, three pieces of cheese, a squirt of ketchup, a big dollop of mayonnaise, some lettuce, an onion and a tomato on top and say, "I just wanted to make sure we didn't leave anything out, take off what you don't want." Can all of that other stuff be removed? Yeah, for the most part...sort of.


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## Tendean17

Andy Wehmeyer :
We've been testing a bunch of head units for operation with MS-8s Un-EQ feature, which is based on correlation of an MLS sequence with the measured output of the head unit. What we've found would shock many of you. The UN-EQ algorithm works really well when the head unit's convertors are of reasonable quality, but some of these things are terrible--in fact, one of them drops a sample every two milliseconds. This, of course creates all sorts of problems with digital EQ, which requires that samples remain intact. 

Can you hear it if you connect an analog piece of equipment to the RCA outputs? No. 

FWIW, however, NONE of the OE head units we've tested exhibit this problem and, on balance, have MUCH higher levels of performance than all but the most expensive aftermarket head units. 

THe choice to replace or not to replace isn't as easy as some BS perception of quality based on the number of ridiculous features you'll never use or some marketing BS about esoteric components or build quality. Nothing is better built than an OE head unit, but many of them include some dynamic EQ that's tied to the VSS or the volume control. This creates a coondition in which the product designed to shore-up the output can't do its job if you use the volume control on the OE head. Is that a problem? Only if you don't like the results.

The not so simple fact is, that there are so many variables, that the answer to the OPs original questions is, "depends". 

I find it's a more useful venture if one asks the question, "Is my ability to enjoy the experience enhanced or degraded by the use of this component?" and applies some judicious caveats to the answer. In fact, the experience may be enhanced in one regard and degraded in another
__________________________________________________ ____________

donkeypunch22 :
_Andy, in what order does the MS8 do it's tuning? In other words, let's say I'm trying to manually do what MS8 does, where do I start? Should I level match first, then time align, then set up the crossovers, and then set the parametric EQ? Thanks!_ 

Andy Wehmeyer :
Hey DonkeyPunch,

The order depends on the tools you have to work with--well...somewhat. I'll assume you have time alignment and also assume that you're not using any matrix processing--like Dolby PL2. 

Un-EQ is really important if you'll be using matrix surround processing because those processors use phase to determine front and rear steering. Ordinary frequency-domain-only Un-EQ won't do because many OE systems use some time alignment in the factory amp. Simply flattening the frequency response in the frequency domain and looking only at the right and left output channels separately isn't enough. The delay has to be removed, especially if there are different delays for different frequency bands. Those delays look like phase shifts to a matrix processor, and if you have 5.1 or 7.1, some frequencies will be steered to the rear. That's no fun. 

Anyway, here's the procedure I use for manual tuning. MS-8 is designed to provide the same outcome, but the tools are different, so the steps inside the box aren't exactly the same and don't correspond to the order in which information is entered in setup. 

1. Time alignment. This should be done without any low pass filters. Don't try to do this all by ear. If you have a mic and a PC, there are plenty of inexpensive programs that will allow you to make impulse response measurements. If you'll do this by making acoustic measurements, it's important to allow woofers and midbass drivers to output high frequencies because they make it much easier to locate the first peak in the impulse. This is a long and somewhat complicated explanation, so let's just say you're willing to take my word for it. 

If you don't want to make acoustic measurements, then just use a tape measure. that's good enough. Digital processors usually run at 44.1k or 48k, and the minimum amount of delay that's possible is a single sample--if the processor runs at 48k, that means 1 sample is 1/48,000 of a second. If sound travels at 1132 ft per second, then one sample equals about .28". That's plenty of resolution, so don't freak out and go on some tirade about what a piece of **** the processor is. That would only make a difference at high frequencies, and we don't hear phase very well above 1k. Measure a straight line from the center of the speaker to the center of your forehead. Good enough.

2. Using an RTA, look at the useable frequency response and bandwidth of the separate speakers. If you're bianping or tri-amping, this is easy. If you're using passive crossovers, then look at each channel separately. Basically, you want to be sure that you're not asking speakers to do something they won't do because of loaction or installation. Never cross a tweeter lower than 2x its resonance if you'll apply anything close to its rated power. For 1" car tweeters, 3k is a pretty good rule of thumb. Set the crossovers in a region where both speakers to be filtered have good output. For example, if your midbass speaker starts rolling off at 120Hz and is -12dB at 60Hz, setting a crossover at 60Hz won't work, no matter how much you wish it would. High pass filters protect drivers and low pass filters provide the blend between the bands. Use steep filters in cars--24dB/octave is plenty. All of this 48dB/octave or greater BS is just a waste of processing power. I'm sure I'll get flamed for that, but I'm right.

3. Combine the speakers that make up one of the front mains--left or right. Leave the subwoofer off. Tune the frequency response of that according to your target. I've posted my target response on this forum at least a hundred times, so I'm not going to type it again. Once that's done, store the graph in your analyzer in a way that makes it easy to match when you do the other channel. Turn that channel off and turn the opposite channel on. Tune the other channel to match the frequency response precisely. Levels should match too. 

3. If you have a center channel, tune it to match the left and right for the band of frequencies they have in common. I recommend a center channel that plays all the way out to 20k if you have some center steering algorithm. If you have a mono (L+R) center, turn it off and take the speaker out. Sell it to someone who has real center channel processing and put a potted plant in place of the speaker you removed. If you do this, be sure to set up a separate tuning for the passenger's seat so while you drive a passenger around, they can enjoy listening while you suffer.

4. Add the sub. Tune the low pass filter and the EQ for the sub according to your target response. Don't worry about the frequency you choose. Forget about overlap or "underlap" because that doesn't apply unless you're tuning for exactly flat response. Another long explanation that I'm not going to type now. Just make sure the combined target response is right.

5. Listen. If you hear something you don't like, don't tune by ear. Get out the mic and identify the problem. Determine if you have EQ that will fix it. If you don't, save what you've done so far, if you have presets. If you don't have presets write down the settings. Use the EQ to try to fix what you don't like. Once you've matched the channels, adjusting to fit the target curve should be done with the same adjustments on both channels. Don't continue tuning channels separately, because that will screw up the match between the channels. If you have peaks when you combine the channels, tune both channels to remove them. If you have dips, you can add a little energy with the EQ to both channels, but if the improvement doesn't match the amount of boost, don't try to fix it. That's a phase problem and can't be fixed in the frequency domain. You'll have to live with it, wait for a better processor or move the speakers. 

That's the procedure I use. It's essential to have a separate EQ for left and right and helpful to have separate EQs for center and sub too. Rear isn't critical. 
Hope that helps. 

MS-8's process is a litle different. You input the crossover frequencies and then it makes measurements. It slices and dices the measurements according to some rules (the algorithm), makes all of its decisions and implements them with a single set of filters per output channel that do time alignment, crossover fine tuning and frequency response correction all in one. That precisely matches the channels according to the target curve--in about 30 seconds. Then, you can adjust the target with a separate 31-band EQ. It isn't an Auto EQ designed for dummies, it's just designed to do the really hard work and the work that currently requires more processing tools than are currently available in any other single processor for cars, efficiently and with less DSP than is included in another product that's designed to do only frequency response based un-eq. Then, you get a tool that makes the fun part of tuning easy. 

Now to the other post about how MS-8 is designed for the masses and isn't appropriate for real audiophiles--this time because it doesn't have a digital input. Sigh.


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## Tendean17

Kameraguy :
_Been listening to the system more with L7 on. As you say zoomer, it takes some getting used to. For the past few days, I have been comparing my car with the MS-8 alongside my other car which I tuned with Imprint (9887 HU). Though the two cars are not the same, the difference in philosophy between how they meant to sound due to processing (regardless of the cabin differences) is obvious to me at least. 

I have been so used to the way the Imprint system sounds...where that the imaging seems a little more 3D (to me at least). It sounds like the instruments are coming from super-focused location that doesn't deviate. It's a very impressive sounding difference. Overall, I love the Imprint sound.

For the MS-8, those same songs i'm listening to sound great as well, but I think I can detect the "steering" of the vocals shift at times vs. the Imprint system. I've made sure to level match my speakers using the amp gains and an SPL meter. This in itself has improved this, but every-so-often I can detect a hint that the vocals are moving around a bit. It's subtle, but this is compared to my other car where the vocals are so focused. Also, The Imprint stage for my tune results yielded a more forward stage, whereas the MS-8 tune I did has the stage sometimes at front, other times just slightly in front or even right in line with my ears. I don't now yet if this is what i want, but some recordings sound pretty awesome this way.

What is a bit hard to figure out is why it happens to some tracks and not all...this is where I am finding it a little tough to improve things. Maybe i'm being super picky though, as this is not a huge problem at all, just noticeable because I have both systems to compare. Now, for the songs that seem to really match the way the MS-8 processes them, WOW, it's a whole 'nother level compared to my 2007 Imprint setup. So i can totally hear the potential.

I am thinking i'll need to spend some time with test tones in the car with the MS-8 to make sure they are all pretty even. I did that with the Imprint system and haven't yet with the MS-8. 

Don't get me wrong though. I definitely LOVE the ease of use in fine-tuning the MS-8. The EQ is a godsend compared to the no frills "take it or leave it" Imprint tuning. I had to install a separate EQ on the Imprint system just to get the finer control needed_

Andy Wehmeyer :
Cool. Nice ears and a great comparison.

MS-8 will sound different on different recordings if you use Logic7. Logic7 steers information from left to right and from front to back depending on two things:

In a stereo recording, sounds that are intended to be placed in the center (between the left and right speakers) are recorded in mono. that means EXACTLY the same in the left and right channels. For a sound that's slightly left of center, it'll be a little louder in the left than in the right. 

MS-8's Logic7 uses these cues to steer left, right and center. Sounds that are mono are sent to the center channel and attenuated in theleft and right. This helps to preserve the stage width, which is always compromised with mono (L+R) center channel processing.

Sounds can also be recorded in varying phase relationship between the two channels. In a live, direct to stereo recording, the room sounds bounce off all of the walls and arrive at the microphones at different levels and with a different phase. Logic7 uses this "phase angle" between left and right to steer front and rear. If the sounds are 180 degrees out of phase, the sound steers all the way rear. 90 degrees out of phase steers halfway between front and rear. 

This does a really good job of reproducing the sound of the room, especially when the room is real. For other recordings, where the room doesn't really exist or for recordings where the mix includes some phase effects designed to do something through a simple stereo system, you may find that Logic7 does something else--you can decide if it's cool or not, but that's why it sounds different with different recordings. I prefer that to the more clinical (some might say "correct") sound of the Imprint tuning because it sounds more believable with the right recording. 

For the most part, I don't believe in accuracy in reproducing the sound on the CD because there's no real reference--so many recordings aren't a "live event". Rather, thay're a bunch of live events, sped up, slowed down, changed in pitch and then mashed together, EQed, compressed and then a room is synthisized. How the hell does anyone know what that's supposed to sound like? I like it when It sounds believable, and that's what we've tried to do with MS-8.


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## Tendean17

Andy Wehmeyer :
So the reason for the three way is to avoid using the midbass (6") in a region where, a) the on-axis response is rolling off, b) where the peak in the response from the major cone distortion mode doesn't roll off as fast as the rest of the response, 3) where the dispersion of the midbass narrows. 

If you use a 2-way, you have to cross the tweeter low enough to meet the midbass, c.3500Hz. You can ONLY use the much higher crossover on the tweeter if you have a small midrange to bridge the gap. 

So, you can pick and choose the "rules" you want to follow, but it doesn't make any sense to follow three of them, blow off the others and then come back and post, "In my experience, Andy's suggestions don't work. 

I do suggest keeping the little mids OUT of the dash and out of the A-Pillars. A-pillars do one thing well--they raise the image. If that's the most important thing to you, then go for it. However, width will suffer. Image size will suffer. 

Since "performance" is subjective, some of you will prefer all kinds of other stuff--see the whole midbass thing. MS-8 tunes basically flat from 160 Hz to 1kHz. For those of you who compete in MECA or who LOVE the sound of your Beats headphones (I like Beats headphones, but not because of the bass, but because of their creative use of multiband compression), you'll want to use the 31-band EQ to boost between 100Hz and 500Hz. MS-8 is not designed to make the 6x9s in your doors move your pant legs. It's designed to place the image of the bass in the front and to allow you to boost the bass with the sub control without changing the apparent location of the bass. Why? Because I like that, because I spec'ed it and because I've made a majority of my customers happy with that for 25 years. This, however, did not make judges happy. They like big, fat midbass. I don't like big fat midbass because when I hear that, I hear much poorer definition in vocals, piano, the lower ranges of all string instruments and the percussive parts of those string instrument sounds. In my experience, that kick-your-ass midbass happens at live shows when the system is loud and the midrange is flat, but it doesn't happen at lower volumes. At lower volumes, the snap of the sound of someone whacking the string of the bass guitar with the side of his thumb sounds percussive, and that's what MS-8 is designed to preserve. If what you hear or what you like is different, no problem. This is why there's an additional EQ that you can adjust.
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Andy Wehmeyer :
It isn't a mystery and it doesn't really have anything to do with the MS-8, except that MS-8 allows you to "experiment" with things like that and eliminates some of the opportunity to second guess the tuning process with left over ideas about what one should actually do. 

With a manual processor, changing the crossover points would necessitate retuning the EQ, but often the crossover points get changed and no one even goes back to look at the EQ. So, crossover points get set with the conventional wisdom that every speaker should be driven as low as it can possibly play to secure the bass in the front and the vocals in the dash. Then, the EQ gets tuned with a single mic and a low resolution tool. Then someone says, "what if I dramatically change the crossover points?" They do. It sucks. They say, "See, the conventional wisdom about super low points is correct." MS-8 makes you retune the EQ, so for all the mewling about the hassle of re-running calibration, it's actually far less hassle than doing the job correctly with a manual EQ.

For what it's worth, in my car, the crossover points are:

SS filter: 20Hz, 6dB/oct
Sub>Midbass> 80Hz, 24dB/oct
Center channel high pass>80Hz, 24dB/oct
Center channel mid to tweeter> 3kHz, 24dB/oct
Front midbass to midrange> 1kHz, 24dB/oct
Front midrange to tweeter> 6kHz, 24dB/octave

Front right and left are in the doors. MB in the bottom, MR about halfway up, tweeter in the sail panel. Center channel is in the center of the dash facing up. Subs in IB in the rear package tray. 

I don't use MS-8 and tuning takes me days. I have 24 active channels and each channel must be EQed separately. I never change crossover points without revisiting the EQ. Every time I've tried the conventional "tricks" (overlapping the sub and the midbass, crossing the MB and sub over much lower, changing the polarity of a midrange, running the center without a tweeter, using 6dB slopes for a "better blend"), the performance has always been worse. 

So, my story is:

1. Don't mount anything but the center channel anywhere near the windshield.
2. Keep speakers out of the A-pillars.
3. If tweeters have to go in the dash or the pillars, cross them high.
4. Use steep slopes
5. Choose crossover points to keep drivers safe and consider dispersion when you choose. 
6. DO NOT OVERLAP FREQUENCY RANGES.
7. Use a center speaker WITH A TWEETER.
8. Use a center channel ONLY if you have a steering algorithm.
9. Always retune the EQ when you change the stuff above.


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## Tendean17

*Measurement and Setup*

Andy Wehmeyer :
The deal with covering the tweeters is that ALL automatic time alignment setting algorithms look for high frequency content to determine the location of the speakers. If you use passives, then MS-8 (like all other devices) will locate the tweeter, because it has more high frequency content. Covering the tweeter causes it to locate the mid, which is where TA is most beneficial. Then, the EQ will fix the "image" at high frequencies, which is more effective anyway because we don't hear phase differences very easily at high frequencies. 

Disconnecting or covering the tweeters for the first 4 measurements is definitely not correct. Only the first in each of the seats..
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Andy Wehmeyer :
In this case conventional "wisdom" is definitely wrong. 

Crossing midbass drivers over at 45Hz isn't necessary. You don't have to do that to get bass in the front and no driver (except for a subwoofer because there's no other way to do it) should play at their resonance frequency. Speakers make the most distortion there. Your subwoofer is much better at making 45Hz than your midbass driver is, no matter what
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Tendean17 :
_I've installed MS-8 .. been finished today .. So i'll run the processing setup. I want to ask about the position of Driver Seat and Passenger Seat for cars with the Right Steering Wheel (Driver's Seat position is on the right). No User Guide about this. I search .. never discuss about this also. Sorry if i'm wrong guys ..

When doing Acoustic Calibration / Measurement in the Drivers position in 1st measurement, where should I sit .. on the left or the right seat ?

In case on the Right Seat as Driver's Seat ..
Driver's Seat> Acoustic Measurement 1of4> Look Forward -> Go
Measurement 2of4> Look Forward -> Go
Measurement 3of4> Look Driver Side Mirror (Turn my head to the Right) -> Go
Measurement 4of4> Look Passenger Side Mirror (Turn my head to the Left) -> Go.
And so for others Next seating position.

Is that the wrong way or it should be no problem ?
Thanks_

acidbass303 :
Yes it doesnt matter, i drive a right hand drive vehicle too.
Just follow on screen prompts and look to the drivers side mirror when it asks to and the passenger's side mirror when it prompts. It takes a spatial average.

Andy Wehmeyer :
That's why the manual and the display call it "Driver's Seat" and not "Right front Seat". This way, it's supposed to be completely seamless no matter where in the car you sit to drive. .


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## Tendean17

AndyInOC :
_Quick question. For those of us still playing with sub/midbass blend do you flip the polarity of the sub before or after the sweeps?_

Andy Wehmeyer :
One way will be correct and the other not correct. I suggest running calibration one way, listening for a little while and then running it after reversing the polarity. Choose the one that sounds best.
Or, make a CD with pink noise between 60 and 200 Hz. Then, choose the poilarity (after the process above) that provides the loudest output with that test disc.
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Kaigoss69 :
_Some people have reported a lack of midbass when using a trunk sub. This has been an issue especially in BMWs with the midbass drivers under the seats. If you calibrate without a sub, and let the woofers play all the way down, the midbass is great, but as soon as you add the sub into the mix, the midbass just disappears. It can be helped with the EQ, but not to the level of impact of the "no sub" calibration, not even close.

After having read about the lack of sub T/A recently, and Andy's explanation that it really is not that important, I had an idea. What if I calibrated without the sub, and then added it back in post calibration, using the crossovers in my amp? So I went out this morning for this little experiment. I set the subsonic at 20Hz on the underseat 8" woofers and calibrated without a sub. I then split the signal at the 4-ch amp and high-passed the underseats at 50Hz 24dB/oct and low-passed the sub at 50Hz, 12db/Oct.

The result? - Fantastic midbass and stellar subbass, the best of both worlds!_ 

Andy Wehmeyer :
This is an interesting work-around and is completely credible. In cars, very little EQ is required below 50Hz and this eliminates the level matching algorithm between midbass and subs, which seems to sometimes cause difficulty. I've found that with big midbass drivers and with amplifiers that also include crossovers that level matching sometimes requires several attempts at calibration with different gain adjustments for the sub. 

MS-8 uses 50-80 Hz to chec the level of the sub to match it according to the target with the front speakers. If there's a huge peak there in the sub and the midbass, and the crossover is set lower than that, the result can be a lack of midbass and bass too.
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Kaigoss69 :
_1. Run set-up with 2-way front and no sub. Set the subsonic at 20Hz. Lo/Hi at 150Hz, 24dB/oct (just do it...). Crossovers on amp off.
2. Run calibration
3. Set the amp such that the input from ch 1&2 goes to all 4 channels
4. Enable high-pass filter on amp for underseat woofers. Start with 60Hz, 24dB/oct.
5. Enable low-pass fiter on amp for subwoofer. Start with 60Hz, 12dB/oct
Edit:
6. Set amp gains to your liking_

Andy Wehmeyer :
Yes, this^^^, for now while we finish working on this level matching issue, which seems to be at it's worst in BMWs with under-seat woofers. I listened to 30 MS-8s over the last two weeks in Asia in every car imaginable (except for a BMW and a Winnebago) and nearly every one sounded good. 

For those of you who have an extra channel, you can also map your subwoofer to the front low (in a 2-or 3-way front sytem) and that will treat the subs as fronts and bypass the level matching


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## Tendean17

Andy Wehmeyer :
Check the difference in level between processing off and processing on. If it's a lot louder with the processing off, try calibrating with the amplifier gains LOWER and with the subwoofer gain a litle higher. Then, if the level matching is reducing the level of mids and highs to match the sub, it'll readjust a bit. 
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Andy Wehmeyer :
If it's the snappy midbass that's missing, then look at higher frequencies--1kHz, for example. There's a big difference between the dynamic range that's possible with a 1000 watt amplifier driving a compression driver loaded into a horn thats pointed directly at you with the whole chain being driven by a microphone that's a foot from the drum set and a 6" speaker in the door of a car driven by a 100 watt amplifier from a CD on which the mix has been squashed to a meager 6dB crest factor. If it's midbass MAGNITUDE that's missing, you can put that in with an EQ. If it's dynamics that are missing, MS-8 doesn't squash those. The recording engineer does because the band is in the studio during the postprocessing screaming, "Make it louder! I want it to sound like it's turned up to eleven!" 

I'm not saying MS-8 always tunes he way it's supposed to. I am saying that there's nothing inherent in the processor that eliminates dynamics. 

Almost every time I go to a show here in LA, I'm disgusted by the mix-so much 60Hz "bloom" that the vocals are unintelligible. It's a sad state of affairs. For some reason, that doesn't happen in New York. Saw Ray LaMontagne at Radio City and it was the highest-fidelity thing I've ever heard. JBL Vertec Array and a bunch of processing. See first paragraph above.
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Jprice2708 :
_Sorry for the stupid question, but how do I set the amplifier sensitivity controls? Do I measure the speaker output on the amp with a DMM? I searched but couldn't find the answer.

Also I have a 2000w rms amp running my 600w sub, and was just planning on turning the sub gains right down, as atm I have 50w per side to the tweeters and 100w per side to the midbass. If I just set everything at 2v will the sub be overpowering everything?

The reason I ask all of this is because I tried level matching my speakers by ear, then running the setup on my MS8 (and yes the sweeps were very quiet - I tried -40db through to -20db). Everything sounds great before I apply processing, but as soon as I turn processing to active it sounds atrocious - way too much sub, literally no midbass, and tweeters sound the same as before. I have tried fiddling with gain settings but I'm not having any luck and starting to pull my hair out a bit_

AcidBass303 :
i too was having this problem in the past. here is what i did that worked, and works all the time..
i gather that you have your sub gain all the way down (if not then do so), turn the gain on your midbass a little higher, try the acoustic calibration at -40 at first, if its good then leave it be, if not, try -50 db volume. Basically i think that the MS8 is more sensitive and less forgiving to the louder sub sweeps than the midbass and tweets. i remember Mr Andy saying somewhere that if the sub sweep feels too quiet then it is probably at the right level, and thats exactly true, at the right level, the sub sweep does feel lot quieter than other speakers' sweeps. as a matter of fact, as Mr Andy said, you should not be able to "feel" the sub at all, just "hear" its sweep. so just keep lowering the calibration volume after -40 in -5 or -10 decrements untill you get it right. You might have to increase your midbass gain a little after -40db volume so that their sweeps dont get too quiet. Trust me, it takes a little thinking and some work to be done, but once you are there, it sounds beautiful... have best SQ ever in my car to date now. may be the method i use is not the way it is meant to be done,, but it sure does work for me.

Andy Wehmeyer :
Acidbass, Thanks for the solution. This has been my experience too
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DanMan :
_It seems that there are some who believe that running an abundance of power and setting the gain to a minimum will result in better "sq". Others believe that this merely limits the overall system performance.
Please share some thoughts on this. Sorry if this is beating a dead horse in some way. I realize discussions on gain setting can be that way._

Andy Wehmeyer :
Amp gains should be set to correspond to the output voltage of the head unit plus a few dB. I usually set them for about 9dB additional output. So, if your head unit outputs 4V (it's est to verify this with a scope, a meter and a sine wave track recorded at 0dB), then you would set the gain (inputsensitivity control) at about the 1.5V setting. 

1. The input sensitivity control is, in fact, a volume control. Setting the input sensitivity to 4V when your head unit outputs 1V max will limit the amplifier's output power because at the 4V setting, 4V is required on the input to drive the amp to full power(provided the potentiometer is labeled correctly).

2. Setting the amp gain low does not necessarily increase signal to noise ratio. If the amp circuit is noisy after the gain pot, then setting the input sensitivity for a low value may, in fact, increase the noise. This is uncommon but possible, nevertheless.

3. Setting the input sensitivity at the same level as the max output of the head is a waste. We don't hear clipping on transients very easily and setting the sensitivity this way means the amp can never clip. If you do this, you're giving away a bunch of perceived output and you're ensuring that the recordings with the highest crest factor won't sound loud, but you'll be able to turn the voilume control all the way up when you listen to Death Magnetic (possibly the most poorly produced record of the past 20 years). 

4. Using a line driver that can output 8V, turning it up all the way and connecting it to an amplifier that can accept a maximum of 4V simply provides 6dB of "gain overlap" and will allow 6dB of clipping. There's nothing wrong with that, but you can achieve exactly the same thing by setting the amp at 2V with a 4V head unit and selling the line driver for beer money. 

All of this line driver stuff is silly these days. Their main functions years ago were to provide a higher voltage signal (radios often had only 100mV of output) and to break the ground between the output of the radio and the input of the amp (before differential inputs were common) to eliminate engine noise. If you're using them now and claiming that you love the "effortlessness" of the system or some such crap, you just like a little clipping. Nothing wrong with that, but you don't have to pay extra to get it


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## Tendean17

Andy Wehmeyer :
I have never read a thread so full of misinformation in my life.

1. The input sensitivity control is, in fact, a volume control. Setting the input sensitivity to 4V when your head unit outputs 1V max will limit the amplifier's output power because at the 4V setting, 4V is required on the input to drive the amp to full power(provided the potentiometer is labeled correctly).

2. Setting the amp gain low does not necessarily increase signal to noise ratio. If the amp circuit is noisy after the gain pot, then setting the input sensitivity for a low value may, in fact, increase the noise. This is uncommon but possible, nevertheless.

3. Setting the input sensitivity at the same level as the max output of the head is a waste. We don't hear clipping on transients very easily and setting the sensitivity this way means the amp can never clip. If you do this, you're giving away a bunch of perceived output and you're ensuring that the recordings with the highest crest factor won't sound loud, but you'll be able to turn the voilume control all the way up when you listen to Death Magnetic (possibly the most poorly produced record of the past 20 years). 

4. Using a line driver that can output 8V, turning it up all the way and connecting it to an amplifier that can accept a maximum of 4V simply provides 6dB of "gain overlap" and will allow 6dB of clipping. There's nothing wrong with that, but you can achieve exactly the same thing by setting the amp at 2V with a 4V head unit and selling the line driver for beer money. 

All of this line driver stuff is silly these days. Their main functions years ago were to provide a higher voltage signal (radios often had only 100mV of output) and to break the ground between the output of the radio and the input of the amp (before differential inputs were common) to eliminate engine noise. If you're using them now and claiming that you love the "effortlessness" of the system or some such crap, you just like a little clipping. Nothing wrong with that, but you don't have to pay extra to get it.
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BuickGN :
_100hz to 900hz is the midbass. Midranges play 900 to 5,000. The little 6.5 in the doors sound fine up that high. Maybe it's better that I got the smaller midbasses. I guess what I don't get is what am I gaining by crossing the midbasses down lower? If they sound good up to 900hz, why not use the larger driver to play those frequencies. I know the theory of having all frequencies come from one driver if possible, but honestly, with the stage out in front of the windshield, I can't tell where anything is coming from and vocals sound great. I went with the theory of using the largest driver for a given frequency within reason and so far it's made a huge improvement. It seems like by following the common advice around here, I initially ruined my sound and for no real reason that I can think of._

Andy Wehmeyer :
Perfect. This is correct. There are two big criteria for crossover points. First, you should high pass speakers in their passband. That's above their resonance. This helps to minimize distortion. You should low pass speakers in their piston range (where the dispersion is wide). 

That's what GN has done here and guess what...it works!
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Frank Drebin :
_You have to run the startup CD every time you change crossovers etc. It seems the ms8 forgets the inputs and I got a really strong drivers side signal when I skipped the input test. I got the front components sounding great when i used the CD, and I could only hear the drivers side tweet when i didnt.
Andy, thanks for the tip, i was running the time alignment test at -15 to -20, and i had to trick the ms8 by turning the sub amp gain down_

Andy Wehmeyer :
Yes, if you change crossovers, you have to run Input/Output Setup. MS-8 builds the system and throws away the information as you complete the steps in order to make everything fit in the memory. It saves a series of correction filters per channel and the filters are BIG. 

I suggest choosing crossovers to keep the speakers happy and working within the ranges where their dispersion is wide (when possible), and then tuning the car with the acoustic calibration and the 31-band EQ. Unless you have a really unconventional system, adjusting the crossovers over and over to tune the car (the way we all used to do when all the tools are available all the time) really isn't the right way to do it. Crossovers are not equalizers!

Yeah, it is a pain, but if you change the crossover, it invalidates the correction filter. It may be a pain, but this is one of the reasons that this autotune mostly works and many of the others mostly don't


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## Tendean17

Andy Wehmeyer :
Here's what I suggest to help you get this tuned:

1. Forget about time alignment for a few minutes.
2. If you have an RTA or some other way to let your eyes help your ears with the frequency response, use it. If you don't try to borrow one. 
3. Equalize the left channel by itself to whatever target you find most appropriate. I'll explain below.
4. Turn off the left channel and turn on the right channel. Equalize it so that it is as close to the same shape and level as the left channel. Remember, that the sound of the near side speaker reaches your ears sooner than the far side speaker. Time alignment will fix this. The near side is also LOUDER by 6dB for every halving of distance. You'll need to attenuate the near side so the levels match. Make sure they match.
5. Set the time alignment according to the tape measure. Measure the distance directly from the center of the speaker to the center of your forehead. Doesn't have to be precise to the millimeter, as time alignment processors often run at 48k, so the adjustment increments are about ,28 inches. Just get close. 
6. Add left and right together and look at the curve. Anything that appears that doesn't look like the right and left by themselves is a phase error caused by reflections. If you see big peaks, equalize that by applying the same cut to both channels at the same time. If you see SMALL dips, attempt to fill those in. however, if you have a -6dB (for example) dip and nothing you do will help fill in the dip, don't apply EQ there. It'll sound nasty.
7. Add the subwoofer and EQ both left and right and sub together to get a smooth transition. 

The target curve I suggest to start with is +9dB from 20-60Hz, a smooth transition to 0dB by 160-200Hz, 0dB from that point up to 1k and then a smooth transition down to -6dB at 20k. The high frequency tilt can be adjusted for your preference. You may like a little more high frequency or a little less.
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CraigE :
_… "Unlike a regular EQ, you don't have to find an RTA and tune the car with the EQ, you just draw the curve you want to hear and press "go" and it does the work in implementing your curve."
The press "go" part has me a little confused. 

Is this done prior to calibration?
If you have adjusted the 31 band EQ, and then recalibrate, is this what the MS-8 will try to implement ?
If this is so, then the EQ should be set to flat prior to calibration to get back to the default MS-8 curve_

Andy Wehmeyer :
The 31 band EQ doesn't affect the calibration. Calibrate, then make adjustments with the 31-band EQ. Then if you want to calibrate again, go ahead. The sweeps are not modified by the 31-band EQ.
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Subwoofery :
_If you don't know how to set the amp for 2V, don't worry about it too much (for now ) 

Calibrate it @ -40 volume and listen to the sound coming from each speaker. 
If one noise is louder than another, try to up the gain (@ the amp) on the quieter one 
Also remember that the subwoofer should be heard and not felt... 

Then listen to your system with familiar music 

Not satisfied? Try a different volume for the calibration. 
Not satisfied? Try to play with your gains (@ the amp) and recalibrate. 

Some people forget that the MS-8 is still a processor that needs attention in order to take full advantage of it's potential... I know marketing states plug and play but you really need to play with it and try different things so that it can only reward you with good sound._

Andy Wehmeyer :
Yes, this is right. The sweep levels don't have to be precisely at a certain level for the thing to work. If you can hear the sweeps easily they're loud enough. If after calibration you have no center image and it seems as though the EQ is seriously wrong--like lots of highs and no midbass, then they're too loud. There's no "fine adjustment" required. No need to try -27, then -28, then -29. Try -30. If it doesn't work, then try -40, for example


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## Tendean17

elerner61 :
_Andy, then what does MS-8 do when you perform acoustic calibrations at the different seat positions and those are saved? I would think that different seat positions (as well as Top Up, Top Down) would require different time corrections, not just equalizations. Thx_

Andy Wehmeyer :
OK, That's a good idea...Measure the driver's seat with the top up. When it asks you to move to the passenger's seat, then put the top down. Then, driver's will be top up, passenger will be top down, but the "Front" will be a compromise between the two.

You could also calibrate for "Rear" by measuring the rear right and left seats with the top down while sitting in the driver's seat. then driver's would be top up, passenger would be top up, front would be a compromise between driver and passenger with the top up and rear would be driver with the top down.
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Andy Wehmeyer :
I like this. The important thing is not to determine whether tuning by ear or tuning by machine yields the most pleasing sound, the point is to test the QUALITY of the method. The word QUALITY in this sense is repeatability. In product development the term QUALITY refers to whether or not the product meets the spec. That should not be confused with APPROPRIATENESS FOR THE APPLICATION (does it meet consumer expectations). That's the job of the spec writer. 

The idea here is not to get bogged down in a discussion of whether the target is correct. Rather, it's to test whether one method is better (a more reliable way) to achieve the target.

Cool. 

I don't tune by ear because my eyes are faster. In order for my eyes to be faster, I have to understand what my ears prefer and the equipment that I use to substitute eyes for ears. 

The fact is that humans are better at integrating things visually. If a duck quacks behind you, what do you do? Turn around to use your eyes to confirm that it's a duck, right? OK...OK...unless you don't care whether it's a duck. Then the assumption that it's a duck is enough. OK, Let's say a bomb explodes 300 yards behind you. What do you do then? Turn around to confirm with your eyes that it is, in fact, 300 yards away. Ok...OK...unless you don't care about how far away the explosion was. Then the assumption that your ears are correct is enough. OK, let's say


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## Tendean17

Andy Wehmeyer :
So, when MS-8 runs input calibration, here's what happens:

The signal on the CD isn't random pink noise. It's a very specific signal designed to allow MS-8 to understand precisely what happens in the factory system in both time and frequency. It's also different in right and left, which allows MS-8 to determine whether a channel is left, right, or mono. 

"Input Low" means that there isn't enough level for MS-8 to do what it needs to do and maintain acceptable resolution of the signal, once it's converted to digital. In other words, "Turn up the volume". IF you've turned the volume of your radio all the way up and MS-8 still reads "low", then you need a line amp or you should use the radios's speaker level outputs.

"Input High" means that the voltage of the radio's output signal is too high and will cause significant clipping of MS-8's input--too much for MS-8 to assure low distortion performance. "Turn the volume down" or "attenuate the output of the radio some other way" is what that means. 

"Input None" means that MS-8 does not see the signal that's on the disc modified in a linear way in either time or frequency. If the signal is not sampled at 44.1k, + or - about 0.5%, this will also cause a "Signal None" condition. We'be built sample rate correction into the algorithm and that's what allows the + or - 0.5%. This is a significant accomplishment and one that isn't included in other products of this type. In order for MS-8 to analyze the signal in the time domain, there has to be a baseline, and 44.1k as the sampling rate is the basline.

"Signal Noisy" means that the signal is recognized but that it's so heavily clipped that MS-8 can't use it. 

The reason that shorted inputs would cause a "Signal None" condition is because MS-8's first "question" is, "Is there anything on the input?" A short is a "Something". Then, the next question is "Is the 'something' similar to what's on the CD?"

There's another condition that has been reported a couple of times, and that's a condition in which MS-8 reads "Signal Low" until the volume control of the head unit is increased to a certain point at which MS-8 reads "Signal None". This indicates that there is something non-linear ,that isn't clipping, that happens to the signal at that point. I haven't had an oppotunity to do any investigation, but this has happened in two Audis with the B&O DSP system. 

Once MS-8 reads "OK OK OK", that means that it recognizes the signal, that it's loud enough but not too loud and that the level between left and right is the same, within a couple of decibels. Then, when you give it the command, it measures the relative delay of the signal on each channel, lines up the initial inpulses (and uses another sneaky trick to accurately measure the delay of low passed signals), combines left channels, combines right channels, applies a 200Hz low pass filter and an all pass filter to the mono channels so they'll sum with right and left without phase errors. Then, MS-8 applies the same kind of EQ to the input signals that it uses during acoustic calibration. 

The way EQ is accomplished is another MUCH more complicated explanation.
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Kaigoss69 :
_Is the "image on the hood" result a secret or do you mind sharing how to do this??? I have the same car as the one you described and my image is at the windshield. Inquiring minds want to know!_

Andy Wehmeyer :
Use the 31-band EQ. Try some cut between 500Hz and 2kHz and adjust the level of the center channel. Also, try more or less rear (side) output. This will vary by recording. Really dry studio recordings that have little ambience won't do it (like old Lyle Lovett), but recordings with more ambience or a goodlive recording will (Corinne Bailey Rae--Live in New York). 
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Tendean17 :
_To day a see the MS-Gr8 in phase and out of phase steering using IASCA Competition Disc .. 
"My voice is in Phase now" and "My voice is Out of Phase now" .. WOW !
When Out of Phase .. all sound is steered to my Rear Speaker and no sound in my Front Speaker. 
That's fantastic_

Andy Wehmeyer :
Logic7 steers out of phase (180 degrees) info to the rear.
I'm glad this has finally worked out for you. Cool!


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## Tendean17

*Prepare your system design first* 

rain27 :
_Andy, Is there any way to use the MS-8 with a 3-way passive crossover with midrange and tweeter up around the dash and midbass in the doors??_

Andy Wehmeyer :
Of course, choose 1-way for the front. Yes, it will work. My lengthy explanation isn't designed to say that it's the only thing that works, but that it's the easiest way to get the best sound (no matter the processor). 
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Michaelkingdom :
_Hi, I am running an MS-8 to an Infinity Kappa Four (125rms) to the Hertz MLK 165 comps. The installer says that the passive crossovers that come with the Hertz comps are very good and that I should keep them in the system. I am running four separate outputs off the MS-8, through the Infinity Kappa amp, through the passive crossovers to the speakers.When I do the sweeps on the MS-8 I get separate time alignment for each speaker. 

My problem is that the speakers sound slightly off. The center image is not very clear and I have run calibration 8-10 times. On the MS-8 I am electronically setting the crossover at 2750 with a slope of 6 as that is where the passive crossovers cross. I am wondering if the mixing of electronic (MS-8) and passive (Hertz) crossovers could be causing this murky image that I am getting.

I have heard that the MLK's are power hungry (the box states 300 watts). Should I bi-amp them and use the passive crossovers OR remove the crossovers and run the 125 rms that the Kappa Four amp provides? Is mixing crossovers not advisable?_

Andy Wehmeyer :
Remove the passive crossovers, install a 20uF capacitor in series with the tweeter to protect the tweeters in case something goes wrong and use the crossovers in MS-8. The quality of the passives isn't in question, but they aren't necessary in your system and using them AND MS-8's crossover is messy and serves no purpose. 

Conversely, you could bridge the amp to 2 channels and use the passive crossovers. In that case, you'd choose 1-way for the front when you set up MS-8's channels and crossover. 

Don't Bi-Amp and use both. Of course, when you ask your installer to do this, he'll probably tell you that I'm wrong because I'm just the KJBL customer service guy and I don't know jack...I can't even count the number of times that has happened
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Andy Wehmeyer :
Well, almost. The most important thing that's left out of almost all explanations of using crossovers, whether active or passive is that the target response should be the measured ACOUSTIC output of the speaker. 

What complicates this for designing passive networks is that the passive network is designed to attenuate the output of the speaker by modifying the impedance curve of the system that's connected to the amplifier. That means it isn't sufficient to build a network that has a particular response when connected to a 4-ohm resistor and expect it to provide the right response. Designing passive crossovers correctly is either lots of trial and error using analysis tools (impedance meter and RTA of some kind), done with a computer modeling program, or it isn't "design". 

The passive networks that come with component system packages are usually designed to provide the target response when the speakers are mounted in a baffle and measured anechoically. Additionally, they're usually designed to maintain a minimum impedance close to the DCR of the speaker with the lowest DCR. Once you put the speakers in the car, all bets are off with regard to the frequency response you hear, but the impedance will be about the same. 

For a real explanation, try the Loudspeaker Design Cookbook by Vance Dickason or High Performance Loudspeakers by Martin Colloms


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## Tendean17

Andy Wehmeyer :
Putting a cap on the tweeters in any system that uses active crossovers is good practice--it'll prevent pops from making it to the tweeters--which can damage them. Also, if the amp should fail, it'll prevent DC from killing the tweeters. Usually, you want to choose a frequency at least an octave below your iintended crossover point or lower. 6kHz is too high, but that's not why the system sounds bad.

The woofers need more power and the center would be better if it could play flat down to 200Hz or so. A dome midrange may play that low, but it probably won't be flat. This is why it doesn't sound good--much of the center channel information is lost and isn't routed to left and right because that frequency is determined by the crossover value you enter for the center high pass. If you enter 200Hz and your center speaker won't play that, they it's lost. That's a big deal. 

I'm sorry that it didn't work in your BMW and with the speaker system you installed. The factory speakers in that car are good ones. In fact, the system I built in my volvo uses all factory BMW drivers.

In fact, we have the same system in a car here (one of the marketing guys' kids) and we installed an MS-8 and used all the factory drivers. Awesome. Not quite enough bass for Michael, though. We added a sample of an upcoming powered sub and everyone was happy.

The assumption that the woofers under the seats in the BMW are substandard is wrong and unfortunate. For a low powered system they're great. For a higher powered system, they make seriously good midbass drivers so long as they're high-passed at 60Hz or so

No, this one we have here is the base system. No L7. No center either. Sounds beautiful in one seat. Bass up front, image from pillar to pillar, singer on the hood. 5 minutes to run autotune and 3 minutes with his kid to make some high frequency adjustments because he likes it that way. Saved that as a preset and saved flat as another. He demonstrates it all the time for people who come to the office and italways gets a "wow, really?" 
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Thehatedguy :
_Andy this might be a dumb question, but when using 12 dB XO settings for the MS-8, do you still need to connect the speakers in phase at the amp, or reverse phase since LR12 has 180 degree phase flip?_

Andy Wehmeyer :
Connect all the speakers in proper polarity. MS-8 will switch the polarity according to the crossover slopes you input. I suggest 4th order.
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Andy Wehmeyer :
I don't recommend gradual slopes in cars for crossovers. For infrasonic filters, they work fine. 1st order linear phase crossovers are OK in rooms where we hear mostly the sound of the speaker and less of the room since the reflecting surfaces are far away (inverse square law). In cars, the reflecting surfaces are very close and also close to the speakers. the frequency response of the speaker matters only a little in cars, because the car's response governs. For this reason, it's best to keep speakers from overlapping--prevents even more sources from playing the same frequencies. Plus, it helps to eliminate the high frequency cone distortion modes from polluting the off-axis response, which makes EQ more difficult. This is especially effective for a 3-way system in the front
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Briznow :
_I was wondering more along the lines of passive crossovers. If I've got a passive LR2 between the tweeter and woofer of my center channel, surely the MS-8 can't do anything with the polarity of the drivers (relative to each other) on the other side of the network?_

Andy Wehmeyer :
No, MS-8 can't change the polarity of the drivers separately if they're connected to a passive network, but the polarity reversal, if required, is probably included in the passive network. This, of course, depends on the competence of the passive network's designer. Don't stress over that. Connect + to + and - to -


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## Tendean17

Andy Wehmeyer :
Crossover points should be chosen according to the ACOUSTIC response of the speaker, not based on the electrical response of the signal going TO the speaker. A 24dB/octave LR alignment as a speaker crossover refers to the ACOUSTIC responses of the speakers modified by the crossover. To do it any other way is to apply filters almost randomly. The only thing that qualifies the "almost" is that at least you know the ouptut voltage of the amplifier at various frequencies. 
__________________________________________________ ____________

Andy Wehmeyer :
Although the OP's question pertains only to crossovers, neither active nor passive crossovers are adequate to tune the response in any car. An equalizer is required. 

The benefits of active are that the circuit can be designed to do a little EQ by choosing non-standard alignments to smooth the transition. Does this change depending on mounting location? Sure. That happens whether you're using active or passive. A simple active crossover provides a range of adjustability that most passives don't, but the passive provides this opportunity to choose non-standard alignments that the aactive crossover doesn't. One is not necessarily better than the other.

As far as insertion loss goes, it's almost a moot point, no matter which doctor mouth is spewing the info. Any passive worth its salt has a DCR that's low enough not to matter. Varying the impedance is how a passive network works and the impedance within the crossover region is NOT parasitic resistance. 

Actives do relieve the amplifier from reproducing information that will never make it to the speaker, and that may be helpful in terms of available output power.

Finally, I know exactly how both Gary Biggs and Mark Eldridge tune their cars. Both cars sound great. They also sound very different. I can say, for certain, that all of this nonsense about aiming mids and midbass drivers can be eliminated with a proper understanding of dispersion, bandwidth and filtering. It's very simple. Use the speakers within their piston range, and aiming isn't necessary. This is the benefit of a three-way system, especially when a 6" or larger midrange/midbass will be used. 

I've never seen anyone rebuild their dashboard and determine a shape bsed on anything scientific or on any frequency response measurements that confirm the new shape's appropriateness or anything of the sort. It's usually to "prove" some hairbrained hypothesis and rarely makes an improvement significant enough to justify the time and expense. 

One is not better or worse than the other. They're just different.
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BuickGN :
I figured I would post my latest experience, it has nothing to do with the current conversation but maybe it will help someone somewhere. 

I finally took a step back and reassessed my equipment. Since I installed the MS8 (going from passives) I've lost dynamics and midbass. Up front bass and overall stage height has been good.

I figured I have a pair of 15s that will play into the mid range, I made a bad decision and got the 6.5" mid bass instead of the 8" for $20 more due to ease of installation and I have a 3" dome that doesn't like to play real low.

After reading many posts on here I was trying to make my domes play as low as physically possible and the mid bass between 63 and 75hz. I've never bottomed the speakers but I've had all kinds of weird issues since the MS8 was introduced and I lowered crossover points. It was to the point the MS8 was going up for sale and I was going back to the passives. I didn't even know why I was going for the low points, I just saw everyone else doing it.

So I started over. I kept the same 20hz/6db for the subsonic, 100hz/6db for the sub to lo, 900hz/24db for the lo to mid and 5000hz/24db for the mid to hi. Also 100hz/24db for the 6.5" center.

What I've been rewarded with is number one, repeatability between tunes. The MS8 was so erratic before, now it's very consistent. Stage went from high but fuzzy to sharp and defined. Midbass and dynamics are the best I've ever experienced. Even at 100hz, the subs still sound like they're coming from up front. For this entire week I've been making up reasons to drive the car just to listen. I can finally re-calibrate and not worry about getting a bad tune. The bad part is I've been driving the 90 mile round trip to work instead of taking the company vehicle but for once I now just enjoy the music and don't even think about the system which for me is a serious win. I've been attending as many live performances as possible lately and while it's not at that level and never will be, if you close your eyes it's not completely unbelievable that you're at a live performance.

I find that when it sounds good I tend to listen at lower volumes and with less boost in the sub bass. I don't mean to do this but for some reason I tend to boost the bass and crank the volume over time when it doesn't sound right. The clarity is unreal. I no longer regret spending what I spend on the front stage and the Dyns were worth every penny. For a while, they were sounding worse than the factory speakers. Another interesting thing is at seemingly low volumes, its hard to talk over the music. Maybe less distortion??

Another huge difference is I'm not constantly adjusting everything. It sounds good on every type of music and I don't have the constant need to adjust. In fact, it's right where the auto tune left it with the exception of occasionally turning the sub level down on that rare CD that's recorded with gobs of bass. Otherwise, everything is flat which is a first since I've owned this thing.

So I probably wasn't giving the MS8 a fair chance. I guess my lesson to myself was to play each driver in it's most efficient range, there's only so much the MS8 can compensate for. This whole time it's been user error on my part. 

I never thought I would say this but the MS8 is an amazing product and for the first time I don't see myself replacing it with anything else. I can't believe what some big crossover point adjustments did to the system as a whole.


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## Tendean17

Andy Wehmeyer :
I like this. The important thing is not to determine whether tuning by ear or tuning by machine yields the most pleasing sound, the point is to test the QUALITY of the method. The word QUALITY in this sense is repeatability. In product development the term QUALITY refers to whether or not the product meets the spec. That should not be confused with APPROPRIATENESS FOR THE APPLICATION (does it meet consumer expectations). That's the job of the spec writer. 

The idea here is not to get bogged down in a discussion of whether the target is correct. Rather, it's to test whether one method is better (a more reliable way) to achieve the target.

Cool. 

I don't tune by ear because my eyes are faster. In order for my eyes to be faster, I have to understand what my ears prefer and the equipment that I use to substitute eyes for ears. 

The fact is that humans are better at integrating things visually. If a duck quacks behind you, what do you do? Turn around to use your eyes to confirm that it's a duck, right? OK...OK...unless you don't care whether it's a duck. Then the assumption that it's a duck is enough. OK, Let's say a bomb explodes 300 yards behind you. What do you do then? Turn around to confirm with your eyes that it is, in fact, 300 yards away. Ok...OK...unless you don't care about how far away the explosion was. Then the assumption that your ears are correct is enough. OK, let's say.
__________________________________________________ ____________

Andy Wehmeyer :
It's important not to believe that any documentation of any test is, in fact, the entire picture. If it measures correct and sounds bad, then there's no sense in trying to convince anyone that it, in fact, sounds good because the graph is good. For years, IASCA contests were plagued by the "flat response sounds bad" view of many competitors. Flat response in a car doesn't have enough bass to sound believable. That doesn't mean that using an RTA is a bad way to tune, but many competitors decided that lining up the dots on the Audio Control wasn't effective so they all bitched until the tool was, basically, thrown away.

The point is that all of these things are tools that give you one view or another. They're all just hints that should help you get to a final product that you like. Some are more useful than others and practice and understanding will help you sort out what's useful in each of them. 

For example, a third octave RTA is helpful, but for figuring out some things, the resolution isn't fine enough. However, switching to 1/24th octave provides a more detailed picture, but it's easy to get bogged down into trying to eliminate high-Q peaks and dips that aren't audible and in some cases, "fixing" them sounds worse than leaving them alone. If you hear a peak but your 1/3rd octave EQ doesn't indicate that it's there but you're sure you hear it, that's a signal that you need to dig deeper with a higher-resolution tool or a different one. 

An RTA doesn't display phase directly, but it is possible to infer a phase problem from the frequency response graph. Trying to make a measurement that will provide a graph that will allow you to pinpoint the phase problem witih an impulse response measurement is really difficult because in addition to displaying the phase of the direct sound, the phase of reflections are included. If you've ever looked at a graph of the phase response of a speaker in a car, it's very difficult to decipher what's going on. If you suspect a phase problem, a mono sine sweep or narrow bands of mono pink noise and your ears can be a much more effective tool for determining the source of the problem. Mono signals should seem to come from a point inbetween the two speakers. If, during the sine sweep the tone seems to come from the center but over a few frequencies the speaker locations are the source of the sound, those frequencies are the ones that are out of phase. 

If you think you hear something, then go find a tool to help you figure out what it is. It's just the scientific method--One experiencees something, One develops a theory about the cause, One sets out to prove or disprove the theory. The trap is in thinking that any of this can be PROVEN in all cases. Real scientists don't get mad when someone disproves later what they've proven years ago...they're often happy that there's more and better information. 
__________________________________________________ ____________

Andy Wehmeyer :
The backwave isn't going to make it through the dash in any way that will create problems. Make sure the baffle doesn't allow big leaks through the grille. No need for an enclosure. 

FWIW, I just came back from Asia where these Hybrid-style A-Pillar pods are super popular--I'm guessing because stage height is such an issue--I'm guessing thanks to the whole competition thing. Apparently the EMMA disc has a track where thelistener is supposed to distinguish between a triangle struck upwards and downwards. In any case, the whole thing is totally out of control. I've seen 6" speakers mounted in A-Pillars in "enclosures" that aren't any bigger than the outside of the basket. The problem with this is that these types of installations turn a full-range driver into a super high-Q midrange that doesn't play any bass and has a peak in the response that can't be tamed by anything. 

Speakers have an integrated high-pass filter and that's what the Thiele and Small parameters describe. It's caused by the interaction of the suspension and the motor. An enclosure does two things--it contains the "backwave" and it stiffens the suspension which raises the frequency and Q of the "built-in" high pass filter. That limits the bass the speaker can make. An electronic crossover is also a high pass filter and it's response combines with the speaker's high pass filter to accomplish the same thing, but it does it by limiting the power that's sent to the speaker. 

This means that so long as the front and back of the speaker are pretty well isolated, there's no need for an enclosure if you'll be using an electronic filter


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## Tendean17

Andy Wehmeyer :
I'm not saying there's NO benefit in better speakers. I am saying that for people on a budget, the money is better spent in buying competent speakers and a real EQ than in buying high-end speakers and no EQ. If you need your car to play loud and have a bunch of power, then you need good-sounding speakers that will handle lots of power
__________________________________________________ ____________

Andy Wehmeyer :
Certainly the speaker is a MUCH higher distortion device than an amplifier. Even a Class D amp can be extected to perform with less than 1% THD. In fact, the CEA rating standard indicates 1% as the level at which output power is rated. You'd be lucky to get even close to 5% if you crossed the speaker over well above resonance--any speaker. There are plenty fo kinds of distortion, but the one that's easiest to measure is simple--frequency response. 

I'd go one step farther than Erin, however--the CAR is the weakest link. For those of you who have an RTA, try this simple experiment. Connect one channel of the RTA to the output of your head unit. Connect the other channel to the output of your amplifier, through an appropriate voltage divider (unless your RTA is designed to handle more than a volt). Play a pink noise track and check out the difference. Then, keep one channel plugged into your radio's output (this is the reference) and measure the response of the speaker with the microphone placed about an inch from the speaker's dustcap. Hmmm...similar, but not exactly the same (The difference is distortion). Then, place the microphone in the driver's seat, close the door and make the same measurement. 

Do this and you'll stop freaking out about the difference between some esoteric amp and another, about cables, and even about speakers. 

Then, spend a month optimizing the installation of the speakers, etc for equal pathlengths, and all kinds of other stuff and make the same measurement. Improvement? In the sound maybe, but not much in terms of frequency response. 

This is why an EQ is an important tool and why all of this focus on the little stuff is unimportant. I work for a company that makes most of its money selling speakers, and even I'll tell you....speakers don't matter so much so long as they're not badly designed


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## Tendean17

Andy Wehmeyer :
Considering off axis response in the design of a speaker system is definitely not a myth, but insisting that the off axis response should be exactly the same as on axis response isn't the best design goal, especially in a car where MUCH of the sound we hear is reflected. 

The link below is a good place to start, although it isn't an explanation of what happens in a car.

http://www.harman.com/EN-US/OurComp...ents/White Papers/LoudspeakersandRoomsPt2.pdf

In a car it's sufficient to design a speaker system that won't have any obvious holes or peaks in the response due to drastically different speaker directivity at crossover points and then to equalize the response at the listening position (essentially the power response) so that it has some substantial bass boost, which is necessary in small rooms, and a high frequency response that falls gradually from about 1k up to 20k. With the exception of the bass boost, this curve looks like the power response of a speaker designed to sound good in rooms. 

It's the directivity index that describes this loudspeaker parameter. There's a much more in-depth explanation in Floyd Toole's recent book, "Sound Reproduction". 
__________________________________________________ ____________

Andy Wehmeyer :
The benefits of active are that the circuit can be designed to do a little EQ by choosing non-standard alignments to smooth the transition. Does this change depending on mounting location? Sure. That happens whether you're using active or passive. A simple active crossover provides a range of adjustability that most passives don't, but the passive provides this opportunity to choose non-standard alignments that the aactive crossover doesn't. One is not necessarily better than the other.

As far as insertion loss goes, it's almost a moot point, no matter which doctor mouth is spewing the info. Any passive worth its salt has a DCR that's low enough not to matter. Varying the impedance is how a passive network works and the impedance within the crossover region is NOT parasitic resistance. 

Actives do relieve the amplifier from reproducing information that will never make it to the speaker, and that may be helpful in terms of available output power.

Finally, I know exactly how both Gary Biggs and Mark Eldridge tune their cars. Both cars sound great. They also sound very different. I can say, for certain, that all of this nonsense about aiming mids and midbass drivers can be eliminated with a proper understanding of dispersion, bandwidth and filtering. It's very simple. Use the speakers within their piston range, and aiming isn't necessary. This is the benefit of a three-way system, especially when a 6" or larger midrange/midbass will be used. 

I've never seen anyone rebuild their dashboard and determine a shape bsed on anything scientific or on any frequency response measurements that confirm the new shape's appropriateness or anything of the sort. It's usually to "prove" some hairbrained hypothesis and rarely makes an improvement significant enough to justify the time and expense. 

One is not better or worse than the other. They're just different.
__________________________________________________ ____________

Andy Wehmeyer :
There are a couple of issues here.

Sounds that are recorded so they appear in the center are mono. That means they are precisely the same in both channels. In order for you to hear them in the center, your ears have to hear precisely the same sounds from both of the speakers. Since you can't sit in the middle of your car, time alignment can fix this issue for one seat. Remember, you have to hear precisely the same thing from each speaker--that means the levels from left and right have to be the same AT EVERY FREQUENCY. Time alignment is a very easy thing to adjust--measure the distances and enter the numbers. If you have to convert to time, then do the math and enter the numbers. That'll get you close enough. Precisely matching frequency response and level is NOT AN EASY THING TO DO. In a car, 4 or 5 bands of parametric EQ aren't enough. You MUST have separate EQ for left and right and unless you're Supertweaker, plan to spend a long time over several sessions to get it right. Setting time alignment and then wondering why the center image isn't rock solid is only doing half the job.

Also, when you get this right, expect that you'll have to spend some tiime getting used to what you hear. In most modern recordings, MOST of the information is recorded in mono or damn close. The center image will be loud and you won't hear the right and left speakers. That's a tough thing to get used to and even IASCA judges have a hard time with it. They say things like "Wow, the center channel is too loud, The stage is narrow...blah blah blah...". 

be sure there's no huge peak at 45Hz and make sure the transition from 60Hz-160Hz is smooth. The response should be flat from 160Hz through the midrange


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## Tendean17

Andy Wehmeyer :
Placement and aiming aren't the same, and I certainly didn't intend to lead anyone to believe that placement isn't important. It is, but how important depends on the rest of the tools you have to work with and whether you need the car to image in both front seats. 

Patrick is right about the aiming thing and that's what I was intending to suggest. Use the speaker in a range of frequencies where the dispersion is wide and precisely pointing the speaker at the listener isn't necessary. Tweeters ought to be aimed, because in cars there typically isn't room on the mounting surface for waveguides. If it's a custom installation and you can design an appropriate waveguide, the benefits are big. Or...you could buy a component set that includes a waveguide for the tweeter .

Even with tweeters, the laser-pointer method is nonsense--unless you're using a 3" dome and plan to strap your head to the headrest.

I find the best solution is a 3-way in the door, tweeters in the sail panels, a big center channel and some kind of processing to extract the center information if 2-seat imaging is necessary. If only one seat imaging is necessary, a 3-way in each door and delay works fine. If only one seat has to be optimized and you want to go nuts (and have someone who loves to write cool code and is an accomplished inventor) the 3-way in each door, a center channel and a processor that uses some crosstalk cancellation and adds early and late reflections is lots of fun. That's what I have currently, but I'm lucky.
__________________________________________________ ____________

Andy Wehmeyer :
Some investigation of the frequency response of the speaker both on and off axis (not in the car) may reveal that this is a directivity issue and that although the speaker may have flat response when measured on axis, the off axis response includes a hole at the crossover frequency. Put that in a car and the response you hear (the power response, modified by the shape of the reflective surfaces) includes the hole. That's what I've been explaining all along. 
__________________________________________________ ____________

Andy Wehmeyer :
Kick panels are great for fixing path length differences but they're terrible for frequency response. Often there's a big peak and dip caused by the shape of the foot well between 300 and 800 Hz. I think this is probably frequency response related, in the midrange and you've also eliminated many of the reflections from the windshield in the midrange


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## Tendean17

ncv6coupe :
_Andy how many speakers do you run in the front and rear of your car and what sizes are they if you don't mind me asking? You can keep the locations a secret unless you don't mind sharing that 2,_

Andy Wehmeyer :

No secrets from me. Front is a 6", 3" and tweeter in the doors. Tweeter is in the sail panel, mid near the door handle (it's a Volvo s60) and the 6" in the bottom of the door. 

Center channel is a 6" and tweeter pointing up at the windshield.

Rear sides are a 6" and tweeter. Rear deck is a 3" and a tweeter.

Subs are a pair of 10" mounted in the rear deck as IB. Sides and rears play mostly processed stuff at low levels, so amplitude response carefully matched with the front isn't important. All of the speakers are driven with 20-watt IC amps (think head unit power). All of the 6" speakers are 2-ohm DVCs so they each get about 40 watts. Subs are driven with an old JBL BP500.1.
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Andy Wehmeyer said:


> OK. Here are a few pictures.
> 
> The first one is the door speakers. In the bottom is a dual 2-ohm coil 6" midbass behind the factory grille in the front. There's nothing behind the factory 4" grille in the back of the original grille at the bottom of the door. that's a stupid place for a midrange. The mid in front of the door handle is a 3" (custom installation of that speaker was courtesy of Gary Biggs). The tweeter in the top is a basic 1" titanium dome with a rubber surround. All of the speakers came from our OEM group and are all used in Mercedes Benz systems.
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> The next picture is the monitor in the dash and the factory center channel grille above it. Under that grille is another one of these dual coil 6" speakers and the same tweeter. The 6" in the dash is designed as a midrange--it has a slightly larger magnet and the cone shape is a little different for flatter high-frequency response.
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> Next is the control knob (a Logitech Space Navigator) and the touchpad mouse thing behind it in the console.
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> And last, but not least, is Audiomulch with some signal processing VST plug-ins. There a little EQ in here, but mostly it's channel gain, the bass boost and cut control from MS-8 and a custom spatial processor (on the bottom) courtesy of our DSP development group. The rest of the EQ is in the amps in the trunk. No pictures of those for today.


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## Tendean17

Andy Wehmeyer :

OK, Once Again, my flickr account doesn't work and I don't have time to figure out why. Sorry. I'll have to do this long hand:

1. We've been through this before, but here goes again. At frequencies with wavelengths that are long compared to the diameter of the cone, sound is radiated in ALL diretions--front, back, and sides. As frequency rises, radiation towards the rear diminishes and at very high frequencies, sound is radiated into a narrow space directly in front of the speaker.

2. If you think about that in terms of measuring the frequency response of the speaker at various angles, you'll discover that the frequency response is pretty wide in front and low frequency only behind. This happens for ALL speakers. 100Hz is BASS for a 4" and sound is radiated front, back, sides, etc. 500Hz is bass for 1" tweeter. 

3. we put speakers in baffles and boxes to isolate the front wave from the back wave so we can hear more low frequency. The baffle or box prevents cancellation, right? If the sound only radiated towards the front, we wouldn't have to worry about cancellation, right? The baffle also helps to increase the low frequencies by reflecting the sound that radiates toward the rear back into the front-going wave. A horn does this same thing, but it just keeps folding the off-axis response back into the on axis response. The angle of the walls and the shape of the mouth determine the radiation pattern. A baffle is a simple dispersion controlling device.

4. When reflected sound meets direct sound, the reflected sound is delayed compared to the original sound that created the reflection. The direct sound and the reflected sound will be out of phase at some frequency and multiples of that frequency. That's comb filtering, and it's no big deal, but the lowest out-of-phase condition is a kind of big deal because the width of the suckout is pretty big. 

5. We use level at high frequencies to determine the location of sound in the lateral plane (side to side) and phase (or time) as frequencies go lower. At really low frequencies, we don't use level very effectively. At the top of the midrange both are important. It's not a strict cut-off. In fact, from 1kHz to 3kH, we don't use either very well. 

6. When there are two sources for a sound that are identical in frequency and time, we hear a phantom source in between. That's why we hear a center image in a stereo system. If we have a speaker and a reflection that have the same frequency response, we'll hear a phantom image inbetween. If the frequency reponse of the reflection is NOT the same, then the image will be placed differently for sounds at different frequencies. If 1kHz is louder in the reflection, 1kHz will image closer to the reflecting surface. At the frequency where the speaker and the reflection are out of phase, we'll hear two images (or no image, depending on your perspective). This causes images to wander around. 

7. When you EQ or delay a channel, you EQ or delay the reflection in the same way. You can't do one without the other--that's the law. You also can't cover the glass if you want to drive the car. 

8. At home, we can use this reflection easily to create an image that's wider than the speaker and a speaker with constant directivity (similar on and off axis response) does this better than a speaker with a jagged off axis response. the reflection is more similar to the direct sound because the walls are flat, the room is pretty symmetrical, etc.

9. In a car, the walls aren't flat and the speakers are mounted really close to the reflecting surfaces. Because of this, we can't easily use the side windows to create phantom images. You'll hear it once in a while, depending on the song, and your EQ. Mostly what happens in a car is simple image spread and comb filtering due to reflections. 

10. If we put tweeters in the a-pillars, low frequencies bounce off of everything. As frequency response rises, the reflections will gradually be confined to surfaces forward of the tweeter--including the door glass. low frequencies will also bounce off the door glass AND the windshield. If we put mids and tweeters in the a-pillars, the same thing happens at lower and lower frequencies. This means that the reflections from the dash, windshield, and door glass all have different frequency response and can't be equalized to be the same. Sometimes the image will wander outside the location of the speakers. Then, we play that track repeatedly for everyone and claim to have great stage width. Play another track and the width collapses to well inside the pillars. We don't play that track for demos, right? This depends on the frequency response of our reflections and how we have time alignment set. So...

11. When we put speakers in the a-pillars, we hang them in front of a bunch of reflecting surfaces which will all turn into additional radiators with varying frequency responses. 

12. If we make ONE of those surfaces the baffle, then we eliminate it as a troublesome reflecting surface (depending on your perspective and whether you want to demo the same track all the time) because the reflection from the baffle happens at almost exactly the same time as the direct sound. 

13. If the speakers are in the doors, we don't have the high-frequency reflection from the door glass to contend with because it's essentially the baffle and the reflection reaches out ears at almost the same time as the direct sound. We still have to contend with the reflection from the windshield, but it's farther away--and remember, sound is attenuated by 6dB for every doubling of distance. For the sum of two sounds, the louder one dominates, right? If the reflection is attenuated, its frequency response has less influence on the sum. 

14. If we use the speakers in the range where they have wide dispersion, we don't have to aim them because sound is radiated into all angles. makes it easy to mount them in the doors. We can aim the tweeter easily because it's small to preserve high frequencies in the direct sound. Low frequencies will bounce off the glass nearby, but the door glass is close and we don't hear phase easily at high frequencies.

15. If we put the speakers in the doors, we have to use time alignment and EQ to get a phantom center and it'll only work in one seat. If we need two seats, then equal pathlngths are the way to go--or a center channel with the right processing.

So, the short story is that by putting speakers in the doors, we simplify the job of installing them, eliminate the most troublesome reflection from the door glass and minimize the influence of the reflection from the windshield. 

Putting a center channel in the top of the dash is a little different. We hope for the best in terms of the big suckout from the combination of the direct and reflected sound from the windsheild and we use the windsheild to provide a phantom image that's a little higher than the location of the speaker in the dash. This works great, but it does provide some image spread for the center because the sound of the center speaker will reflect off the WHOLE windshield and the door glass


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## Tendean17

Andy Wehmeyer :
Excursion quadruples for every halving of frequency. Raising your crossover frequency by an octave can have a dramatic effect on power handling and distortion. So long as the speaker beneath it in your system is operating within its piston range, raising that crossover frequency is a good idea. 

In my car I use a dual 2-ohm voice coil 6" in the bottom of the door, a 2-ohm 3" in front of the door handle (just above center) and a 4-ohm tweeter in the sail panel. Crossover fequencies are 70Hz, 1kHz and 4kHz, all 4th order sloped. The ONLY reason to install the mid is to make up for directivity issuses with a 6" midbass. The midbass is in the stock location and points directly across the car. 

The center is a similar dual-2-ohm 6" and a tweeter and it's mounted in the top of the dash. Is the 2-way optimum in terms of directivity? No, but having a 6" in the dash to center the midbass and dealing with the hole between the 6" and the tweeter off axis is the right compromise. 

The only reason to choose big midbass drivers is if you ned the car to play loud or you'll be using lots of power. The excursion rule, above, is important. Think about those cheesy little iPod dock drivers. So long as there isn't a ton of power applied, even a 1" tweeter can be a full range driver. The two most important things to keep in mind when designing a multi-way speaker system are excursion vs. power handling vs. high pass filter choice and directivity vs. low pass filter choice. So long as you don't drive the speaker so hard as to make it seriously non-linear, a good EQ can take care of the rest
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acidbass303 :
_Beautiful explanataion mr Andy...Speakers going into doors definitely...
One thing though, do we have to flush mount the tweeters to get the baffle effect ( making them 90 degrees of axis) or can the provided 30 degress pods be used for surface mounting on door? ( which i prefer for my tweeters)_

Andy Wehmeyer :
Aim the tweeters so that both listeners are in a +/- 35-degree window and your're golden. Obviously, the door isn't a perfectly flat baffle, but that's OK.
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Andy Wehmeyer :
I tune MS-8s in cars without center channels all day long and they sound great. A center is sometimes a little better and is definitely better in cars where two seats have to sound good. To say that MS-8 doesn't work without a center is just plain wrong. 

Keep speakers in the front away from the A-pillar and out of the dashboard (except center speakers) and MS-8 does a great job.
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Andy Wehmeyer :
Yeah, what gives with all of the "wideband" stuff? A three inch doesn't make bass and it doesn't make high-frequencies. It's a midrange and is an effective fix for directivity issues between big midrange drivers mounted off axis and tweeters. They aren't full range drivers, unless the only program material you plan to listen to is Paul Harvey.

If it's a center channel and all you can fit is a 3", then use a 3" two-way or add a tweeter
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Andy Wehmeyer :
Be sure to have a separate EQ devoted to the center channel. The timbre has to match the left and right pretty closely, but there's no need to use the same speaker. That's a good rule of thumb for home audio, but it's less important for cars where the response depends more on the location than the original frequency response of the speaker.

The reflections from the glass help and hurt. They'll raise the stage, but you'll have a frequency response problem at whatever frequencies you have constructive and destructive interference. That's why I say get a separate EQ. I've had the best results from firing the speaker into the glass and poorer results from an on-axis placement. The dispersion of the speaker is only narrow at frequencies with wavelebgths that are short, compared to the diameter of the cone. That means that MOST of the reflections won't be different for on and off-axis placement


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## Tendean17

Andy Wehmeyer :
The speakers are unimportant. Originally, I used all the Volvo speakers and added the mids only. I've built cars that sound great using all factory drivers and with cheap aftermarket drivers and great aftermarket drivers. The most important parts of the system are the center channel, the location of the mids in the doors, the ridiculous amount of EQ available and center steering. 

The biggest time consumer was configuring the damn PC and finding an audio interface that wasn't a piece of S&*t. PC audio is not a bigger PITA than it's worth, so long as there's some cool processing that requires a PC, but it's a PITA for playback. I put the PC in so I could use the car as a development tool (running VSTs) and so I could stop using the crappy Aux input adapter I was using for my iPod. I could hear the CAN bus in the audio signal and that made me nuts
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Subwoofery :
_Andy already said many times to use the midbass low in doors, kicks or under the front seats, midrange above the midbass location (still in doors) and tweeter in the sails. 
Also use each speaker below its beaming range and you should be good - no aiming required if used below beaming._

Andy Wehmeyer :
Yes, this is right.
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Andy Wehmeyer :
Getting warmer--this one is on the right track. However, the reflection issue has little to do with DSP. basically, automatic TA can't effectively make a judgement call about what is the true source of the sound, but building a system that a DSP can't figure out doesn't mean the DSP isn't smart or that the design is advanced or better. MS-8 is designed to make good systems sound better. In order to qualify for MS-8 definition of "good" certain principles have to be considered and even followed. This one is a pretty complicated one and one that isn't so obvious.

I'll try to get this done as quickly as possible, but I'm having fun watching posters here zero in on the problem.

Here are a few tips to speed the course to a solution. 

1.Sound is attenuated by 6dB for every doubling of distance from the source.
2. We use level at high frequencies to determine the direction of sounds at high frequencies and phase (or time) at low frequencirs. 
3. We can eliminate a reflection (at least minimize it) by using the surface as a baffle by mounting the driver in the surface.
4. We don't have to be concerned about on-axis so long as we use the drivers in their piston ranges (where dispersion is pretty uniform at all forward angles).
5. Tweeters are easier to aim than larger drivers.
6. Acoustic crosstalk kills stereo (don't focus on this one, but consider it).

Ok, back to work for me. I'll be back later
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Subwoofery :
_Just for fun, since it's better to put the mid up high, where is the best spot for the midbass? Door or kicks? 
Not talking pros and cons, just talking about the best location WITH the MS-8... Thank you Andy,_

Andy Wehmeyer :
Lots of things to consider--If the center is big and can play some midbass, then the location of the midbass matters less. If the center is small, then the midbass below the center's crossover point is steered to the right and left. If that's the case, then thee's a bigger benefit of the more equal pathlengths, since the center midbass is the acoustic sum of left and right.
The drawback of kick panels is that the bottom corner of the footwell often causes a big dip followed by a big peak (between 30Hz and 1k). Stuffing a driver that wants a cubic foot into a tiny kick panel enclosure in many cases seriously limits the low frequency response and creates another big peak


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## Tendean17

Andy Wehmeyer :
Man, I so wish there was a Truth-O-Meter that could be applied to many of the posts on this forum because so many of them cause beginners (and even some old timers) to waste a bunch of time and a bunch of money.

Here are a few truths that may help to sort some of this out:

1. Speaker dispersion is a function of dimensions. For round speakers, the dimension that governs the frequency at which off-axis high frequency attenuation begins is diameter (or radius depending on which math you're using). That's it. Cone materials, cone geometry, phase plugs and the like change the shape of the curve--some on axis and some off axis. The smoothness of the rolloff and the similarity of the rolloff measured at different angles is determined by the stiffness of the cone, which resists breakup modes. those breakup modes create raditaing areas that are smaller than the cone, and the dispersion of the sound that comes from those smaller areas is also governed by the dimensions of those areas. That's why if you look at off axis measurements of speakers, you sometimes see a peak in the response at high frequencies that gets narrower in the off axis measurements and isn't attenuated at the same rate as the surrounding frequencies. One 6" driver may do this differently than another 6" driver, for example, depending on the stiffness of the cone. The high frequency dispersion of one 6" driver is NOT, however, different from another one by any amount worth considering. A HAT 6 is not a wider or narrower dispersion driver than another 6. Sorry guys. That's the truth. 

2. A speaker's frequency response may be tailored to provide flat response at some angle off axis, which will result in a rising high frequency response when measured anechoically on axis. A speaker designed this way will sound nasty in your living room, but might sound good in a car, since we hear the power response in the car (the combination of on axis and off axis response), as high frequencies are attenuated off axis. This is a moot point in any real car audio system because real systems include real EQ, which contributes more to the sound of the car than the choice of speaker brands or even their frequency response. 

3. Expounding on the above: In rooms, we hear mostly the sound of the speaker because the reflecting surfaces are far away and the sound of the reflections are attenuated a bunch by the time they reach our ears. In cars, the opposite is true. We hear mostly the sound of the reflections and less so the sound of the speakers. Changing speaker brands doesn't change this and this is why sometimes when you install a basic set of new speakers in an attempt to upgrade the sound of your car, there's little improvement. EQ is the best way to change the sound of the car. 

3. Acousticians will tell you that you can't EQ a reflection. That's true. You can't EQ a reflection separately from the speaker because the sound of the speaker CAUSES the reflection. In cars, this is still true, but our ears and brains can't easily tell the difference between the sound of the reflection and the sound of the speaker. If we try our best to make sure that the sound of the reflection is as similar as possible to the sound of the speaker, we can EQ the whole thing together pretty effectively. 

4. If you mount speakers off axis, you don't eliminate the on axis response, you just move the on axis response into the reflected sound. This is simply "acoustic EQ" and can be effective but is a much slower process of iteration than dialing a knob to turn frequencies up or down. It's riskier than simple EQ, though, because the on-axis response of the speaker is LOUDER than the off axis response, so by doing this you INCREASE the acoustic crosstalk at those frequencies which narrows the image. This is why A-pillars and speakers firing into the windshield provide a narrower stage than door-mounted or sail panel mounted tweeters. 

5. Small "wideband" speakers are a load of hooey--these things are designed to save money in near-field applications where low cost is important, but there's no sonic advantage to not having a tweeter. There's also little benefit in having "the critical midrange frequencies between 200Hz and 4kHz" emanate from a single driver. In fact, trying to get the same moving coil direct radiating driver to play bass and high frequencies together is asking for doppler distortion, which is audible and doesn't sound so good. This is one reason to use tweeters. The other is explained in point 1, above.

None of these suggestions are opinions, they're facts and if a speaker manufacturer tells you he's found a way around these facts while he's showing you a wacky cone material, new basket, gold-plated phase plug or the like is pulling your leg. If he's showing you an array of drivers and a DSP that includes a beam-forming algorithm, it's probably worth a demo, but not worth plunking down a bunch of money without a demo.

Winning IASCA contests by having the highest SQ score does not guarantee that what the manufacturer is telling you is true. It only guarantees that the judges liked the sound and that doesn't guarantee that you or anyone else will. Winning IASCA contests by pitching the dubious sonic benefit of all kinds of unrelated BS doesn't guarantee that the car sounds better, but it does give an indication of the competence of the judge or the ability of the rules to direct competitors in building a great sounding car. 
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Andy Wehmeyer :
Barring the use of waveguides or some other aperature designed to alter the dispersion of the driver, basically yes. You can alter the shape of the curve and make relatively minor changes. 

The dispersion characteristics of drivers is well understood and well documented among transducer engineers. Disputing the rules is kinda like disputing Force = Mass X Acceleration.

The dispute here on the forums, if you wade through all of the marketing garbage designed to obfuscate the real issues in the hopes of selling a few speakers, regards the appropriate use of narrow and wider dispersion and the misunderstanding seems to be that among many car audio enthusiasts, the pattern isn't well understood to be a pattern that changes with frequency. I've read a thousand times here people writing that small drivers are wide dispersion and big drivers are narrow dispersion. this is insufficient description. All drivers are wide dispersion at frequencies with wavelegths that are long compared to the diameter of the radiating surface. All drivers have narrow dispersion at frequencies that are short compared to the diameter of the driver. 

The disagreement that Patrick and I have had in the past regards the effective use of this "natural" pattern control for round drivers. One way to look at this is to say that if you use the driver in the region where the dispersion is narrow, you can eliminate reflections from boundaries adjacent to the speaker. The answer is yes, but you'd need 15" midbass, 10" midranges, 5" midranges, 3" midranges and no tweeters (or the like) and the crossover points would make VERY poor use of the speakers which are designed to operate in the range where the response is flat and the dispersion is wide. Mounting this system in the front of a car would be damn difficult, too.

Another way to do this is to use horns. The problem with horns is that the frequencies where they are effective in pattern control depend on the dimensions of the MOUTH of the horn. Once again, we have a size and mounting problem for effective pattern control in the lower midrange and midbass frequencies, where that pattern control would be most beneficial. 

Eliminating adjacent boundary reflections is only part of the issue. We also have reflections from boundaries that are near our ears and those cannot be eliminated with pattern control applied to the speakers. 

Since all of the reflections reach our ears at nearly the same time, we don't recognize them as separate events, so they don't add ambience, they just shift the focus of the image. If you use drivers in regions where the frequency response is VERY different on and off axis, then there is a greater chance that the sound of the reflection and the sound of the speaker will cause wandering images. Keeping the sound of the reflection as close to the sound of the speaker as possible will help to minimize the image shift at different frequencies. 

All of this is a crapshoot in a car because the reflected sound doesn't sound like the speaker. My point here is that the difficulty in applying meaningful pattern control in cars makes it not worth the effort if the end is good sound and the means is efficient system design and building. If the end is experimentation (as it appears to be for many DIYers) and the means is a car audio system, then, by all means, go crazy. My objective is to help the first group get to the end as efficiently as possible and to help the second group better understand to constraints within which they'll be working so the experimentation will lead to positive and verifiable results. 

My suggestion is to improve imaging by adding more channels and processing that steers signals. Then, with the imaging somewhat free of the need to precisely match responses for a perfect acoustic sum, equalization becomes much easier and reflections matter less. A center channel in the top of the dash and a matrix processor like Dolby PLII or Logic7 are really helpful in getting a consistent image and decorrelated rear channels, whether by real L-R (see Lycan's thread) or with a matrix processor help to add a sense of space that's larger than the car. 

If this makes you mad, then I'm sorry.


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## Tendean17

Andy Wehmeyer :
Raise the crossover frequency between the midbass and the sub and work on the EQ between 60 and 160Hz. Sounds counterintuitive, but it works. THe rule here is NOT to drive speakers (other than subwoofers) at or near their resonance.

it doesn't matter that frequencies above 100Hz are direectional, what matters is that between 80-200 Hz, a 6" speaker radiates the sound in all directions. Aiming doesn't matter at all--not one bit--zip--zilch--nada. THe problem is the difference in distance from each to your ears (arrival times) and the frequency response at the ftansition from bass to midbass

Raise the other one to 80 Hz too. Then adjust time first, then level, then EQ, then you may have to readjust level.
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Lycan:
I'll second that : a 6" speaker has no choice but to radiate frequencies below 200Hz uniformly, in ALL directions. So up to 200Hz, it does NOT matter how the speakers are aimed. Note well : this is NOT the same thing as saying it doesn't matter how you aim your 6" speaker You really gotta understand the difference between these two statements.

And I'll elaborate on Andy's point about operating a midbass well away from it's resonant frequency (Fs, in enclosure). The reason has little to do with its amplitude response, but lots to do with its phase response. Any driver in a sealed enclosure (including leaky ones, and IB) has a 2nd order high-pass response, phase included, so it's PHASE at the crossover to the sub will dramatically impact it's "acoustic summation" with the sub. The closer you operate the midbass to its resonance, the more its phase will be deviating from zero degrees. So the PHASE response of the midbass-in-enclosure, near the crossover to the sub, needs to be comprehended. This means one of two things : 

1. Be prepared to measure & equalize appropriately (with linkwitz transformer ... yes, on the midbass ... or all-pass phase eq, or combination of both). Remember, we're not equalizing the amplitude so much as equalizing the phase ... so your 31-band graphic or parametric ain't gonna cut it.

2. OR ... simply operate the midbass well above its resonance, to avoid phase problems at xover to sub
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Andy Wehmeyer :
Ahhh...but the real reason not to operate a speaker near its resonance is because that's where it produces the most distortion and at multiples of resonance. That distortion cannot be filtered electrically (yet), and it's high-frequency content that makes localizing the speaker easier. Couple that with all the turbulent air movement when the cone has to move a long way and it's a recipe for winning the "Where's Waldo" game. 

Seriously, minimize the excursion and the system will get well fast.

I have all kinds of all pass filter capability in my car and i've never used it successfully to blend the sub and midbass. It's always more hassle than it's worth. I don't use any delay between subs and midbass either. It's all about amplitude and smooth response froom 60-160Hz. Any phase problem will show up as a frequency response problem too--since the car is small and the wavelengths are long. Just focus on amplitude, remembering that phase problems will present in the frequency response domain too. Start with the midbass, midrange and high frequency speakers first and be sure that right and left sum for a good center image and then add the sub. Start with the midbass crossover at 80Hz, no matter the size of the speaker and add the sub. Adjust the level until you have the amout of low stuff that you require and then plug in the RTA and smooth everything so it's flat from 20-60 and then a gradual and smooth slope down to 160Hz.


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## Tendean17

Lycan :
In the midbass region, below 200Hz, a 6" (or even an 8") driver radiates uniformly in ALL directions. Below 200Hz, these speakers are like spherical light bulbs ... does it matter how you "aim" a spherical light bulb, that shines light the exact same in ALL directions? Aiming will have ZERO impact on localization below 200Hz. You'll still generate the necessary ITD for stereo soundstaging, no matter how they are "aimed". It will NOT be like mono at all ... remember, don't confuse where a speaker is "aimed" with where the sound will appear to be "coming from".

As frequencies INCREASE, above the midbass, aiming will start to matter as the drivers start to "beam".

In summary : below 200Hz, aiming doesn't matter. At higher frequencies where the driver starts to BEAM, aiming starts to matter. So the only answer to the question : does it matter how I aim my 6" drivers? is this : what frequency range are they playing? If limited to 200Hz and below, the answer is no : it does not matter how they are aimed. If playing well into the midrange AS WELL AS THE MIDBASS, then the answer is yes : the midrange "part" of what they are playing WILL be impacted by how they are aimed.
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Lycan :
in the frequency range where ITD's rule, which includes the midbass, midrange and into the lower treble ... stereo reproduction expects that both speakers are heard equally by both ears. The human head simply can't provide any shadowing in the midbass, or midrange ... and stereo reproduction doesn't expect it to. Quite the contrary ... stereo reproduction requires both speakers to be heard by both ears equally (in the ITD region).

Not until the treble, does head shadowing play a role in attenuating the left driver to the right ear (and vice versa). So the term "crosstalk" ... as "negative" thing to be avoided, fixed or balanced ... doesn't even apply, until we get into the treble.

But if your comments are only intended for tweeters, then i agree 

Angling the speakers inward (midbass or midrange) ... both of them ... is simply a way to exploit off-axis attenuation to help solve side-bias, for both front seat listeners at the same time ... something a balance knob can't do. Sure, it's "crude", but often pretty effective if a two-seat car is important to you.
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Lycan :
it's cool .. What many fail to realize about stereo reproduction in the ITD range is this : in the recording or mixing stage, phantom ITDs (corresponding to phantom source locations) are created by adjusting relative amplitudes between the speakers But the entire process expects both speakers to be heard equally by both ears ... the term "crosstalk" doesn't even apply.

But we can also "manipulate" this same principle to our advantage in the reproduction stage. If you sit equidistant between two speakers, and reduce the amplitude of the left one ... the stage pulls right. This has nothing to do with crosstalk (in ITD range), it simply influences the vector sum of the two sources such that the resultant phase (aka, ITD) now "points" right. Again ... both ears are hearing both speakers equally well, but through "balance control" manipulation we've "moved" the stage.

Well, the same technique works in reverse ... if we sit off center, to the left (say), ideally we'd like to attenuate the left side speaker to pull the stage right (towards the center). But what about the other passenger? We'd like to attenuate his close speaker also ... at the same time. That's what angling the speakers (midbass, midrange) does, to a crude approximation 

EDIT : the reason i've called "angling" a "crude" technique is because a speaker doesn't "beam" ... or attenuate its off-axis response ... over its whole bandwidth Far from it, in fact.
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Lycan :
Tweeters off-axis makes sense in environments where :

- the listener is not centrally located
- lots of near-field reflections

Waveguides can make even more sense. The reasons have been spelled out, time and again, on this forum. Stop thinking like home audio ... we're not trying to "duplicate" the home audio environment. We've got a unique set of constraints in car audio, no more or less "valid" than the home ... just different. What we're trying to do is optimize driver placement & signal processing for this environment ... we're not trying to shoehorn or force-fit the living room into our cars.

EDIT : what quality_sound said Maybe the tweets are designed with a rising on-axis response, with the intention of listening off-axis? Also, do you care about both front seat listeners? In the IID range of frequencies, you can't electronically attenuate the near-side speakers for both front seat listeners ... but you can approximate near-side attenuation for both front seat listeners mechanically Are you worried about reflections from your side windows? You should be ... this will impact your tweet aiming as well ...


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## Tendean17

Lycan :
Just a few more random thoughts about the pure folly of "on axis tweeters" in a car environment. Intended to be food-for-thought 

1. How do you aim two tweeters for two front seat passengers, so that both tweets are on-axis for both front seat listeners?

2. Think about the "phantom image" model for reflections. Especially valid near hard reflective surfaces, like glass ... even for treble wavelengths. The "image" model is simply this : there is a "phantom" tweeter, wherever you see the reflection. You can imagine that phantom driver playing, with the reflective glass removed So, lets count how many tweeters are playing (real plus phantom) in the very reflective nearfield, just counting first reflections : Three reflections from left tweeter (left window, right window, and windshield), plus the real left tweeter, plus three reflections from the right tweeter, plus the real right tweeter, for a grand total of EIGHT. Yes ... in a nearfield reflective environment, you don't have TWO tweeters playing, you have EIGHT. Like it or not, in a nearfield reflective environment ... you have an ARRAY of at least EIGHT tweeters playing.

Now ... exactly which ones of these EIGHT are you going to "aim" to be on-axis? And has your aiming taken into account the comb filtering resulting from the delayed arrival from the phantom drivers?

Yes, virginia, that's what the nearfield reflective environment gives us ... like it or not.

3. At treble frequencies, wavelengths much shorter than the distance between our ears, it's all about IID (inter-aural intensity difference) for localization. Even ignoring reflections for a moment, if we care about both front seat listeners, how can we attenuate near-side intensity for EACH front seat listener? Sure can't do that electronically But we can approximate near-side attenuation for each front listener mechanically, by exploiting off-axis attenuation. Of course, this approximation is improved with waveguides 

These are the main reasons why "aiming" tweets in car may very well lead to surprising (or at least, non-obvious) results. It may be that aiming somewhat centrally to minimize reflective intensity ... in other words, aiming so that the PHANTOMS are as OFF-AXIS as possible ... may ALSO result in acceptable attenuation for each near-side listener. Hence, my comment about dome-light aiming 

When you consider reflections, you may ponder this question : 

Do you want your main tweeters MORE on-axis, or would you rather have the phantoms MORE off-axis? 

Bottom line : "on-axis" tweeters might make sense in a larger, less reflective environment for more centrally-seated listeners. But don't try to force-fit home-audio thinking where it just doesn't apply.
__________________________________________________ ____________

Andy Wehmeyer :
This is true for all speakers playing within their "piston range". Aiming a 3" is also unnecesary so long as the low pass filter is chosen in a range where the speaker radiates in all directions. This is a benefit of using 3-way arrangements in the front. 

As I've stated in another long thread about tuning cars, there are two schools of thought about this, though. Patrick prefers to narrow the dispersion through the use of horns and by using drivers in the range where they beam. I prefer the opposite--spread the sound around as equally as possible and EQ the power response (which happens to be the in-car response). Both have their merits and neither are able to eliminate acoustic crosstalk (left ear hears right info and also right info reflected off surfaces close to the left ear, right ear hears the opposite). that crosstalk is what tells our brains that we're in a car (or other small space).


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## Tendean17

Dbiegel :
_Isn't that only if you're using very steep slopes? Imagine, for example, a typical midrange setup: listening to a 3" driver, at 95db, low passed at 6k/12db. It's still 83db at 12khz and almost 90db at 9khz! Unless the particular driver has a high end roll off (and many these days instead have a rising response), it would still be playing about 75db at 20khz! Some of that might be masked by the tweeter, but aiming will still have a large effect on the sound, especially in the 7khz-10khz range. 
I'm curious why you prefer the opposite approach. In theory, narrow directivity helps us get less crosstalk, a higher ratio of direct to reflected sound, and more attenuated "phantom speaker" reflections. In practice, I'm having much better luck with narrow directivity speakers than with wide dispersion domes, in terms of imaging and stage. I got much better tonality with the domes, but that's a a piece of cake to fix compared to poor imaging/stage problems._

Andy Wehmeyer :
Of course that would be the case with the 3" driver, but who uses a 3" up to 12k? Also, below 3k or so, the 3" radiates in all directions. I suppose you could use the 3" as a tweeter from 10K up, an 8" as a midrange from about 5k and up, a 15" woofer as a midrange from 500Hz or so and up, and so on and so forth, but I think you'd need a pretty big car to use speakers in the ranges where they beam as a means of pattern control. This method will completely fall apart in the midbass, as there's just no way to get speakers big enough in the car and in the proper location. 

OF course, horns and arrays can do the job, but they have their own share of problems. A horn may help to eliminate the reflections from boundaries adjacent to the driver, but not reflections from boundaries adjacent to your ears--the window, for example. 

I prefer the low directivity method because it's easier: drivers exist to support it, choosing loactions and mounting the drivers is far simpler and they can be more easily integrated into the car's cosmetics, and finally, successful EQ is much more likely. Big differences between the frequency response of direct and reflected sound make tuning really difficult.
__________________________________________________ ____________

Lycan :
There's an easy way to put a "worst case" limit on off-axis response of a driver of given diameter. It goes like this:

1. Off axis response is attenuated, and experiences peaks & nulls, simply because there are point sources distributed over the surface of the cone ... and these point sources are displaced from each other, in distance and time, as the listener moves off-axis. Given the driver diameter, the "worst case" assumption is that the two point sources on opposite sides of the cone are the only points operating.

2. Pick the off-axis angle where you want to "listen". Simple geometry will then determine the time delay between our two points on the cone. Worst case is, of course, 90 degrees off axis. But this simple procedure will work for any off-axis angle.

3. Write down the transfer function of a simple delay. Pick a frequency, plug it into this transfer function, and you'll have your "worst case" off-axis attenuation at that frequency.

I'll go through the math for 90 degrees off-axis from a 6" driver at 200Hz, if anyone is interested. But i'll tell you this now: you won't find a 6" driver whose off-axis response at 200Hz ... even at 90 degrees ...is even 1dB down, compared to on-axis response 

By the way ... if you think that a driver's off-axis response is essentially the same thing as comb filtering, well ... that's where you would be right


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## Tendean17

Andy Wehmeyer :
The absolute values of the phase at the crossover for each speaker are added for speakers connected in the same polarity and subtracted if one speaker is connected in reverse polarity. Low pass filters lag 45 degrees per order and high pass filters lead 45 degrees per order. 

So, first order HP and LP are either in phase or out of phase by 90 degrees at the crossover, depending on polarity. A second order HP and LP are either in phase or 180 degrees out of phase at the crossover depending on polarity. Third order HP and LP are either in phase or 270 degrees out of phase, depending on polarity.
And 4th order HP and LP are either in phase or 360 degrees out of phase (back in phase) depending on the polarity. 

When the speakers are out of phase by 180 degrees at the crossover, you'll have a pretty deep and narrow dip. When they're in phase, there will be a little bump for butterworth filters. Different alignments are designed to alter this bump or dip. LR filters spread the -3dB frequencies a little bit to flatten the bump. 

Now, all of this is pretty easy to see and easy to realize when we look at summed electrical filters, which is what everyone loves to show in graphs. When these principles are applied to speakers in real spaces, it isn't so easy. Crossovers and alignments, when they're applied to speakers (whether by passive or active means) are intended to provide the target ACOUSTIC output. That means that it doesn't matter what the electrical filter F3 and Q are, what matters is the measured response of the speakers when the filter is applied. We want to hear the proper summing of the output in the proper phase and that's not so simple. 

Because the phase leads or lags (comes before or after) that also means that placement of the speaker affects the phase we hear. So, for example, if the tweeter is crossed over at 3k and the length of a 3kHz wave is 1132Ft/3000, then moving the tweeter 2.25 inches toward the listener will alter the phase at the crossover by an additional 180 degrees. Moving it forward will cause the tweeter and the mid (for 12dB crossovers) to be an additional 180 degrees out of phase, for a total of 270. Moving it back 2" will put them back in phase. 

Also reflections in a car are in and out of phase with the primary sound by varying degrees depending on length of the reflection's path. 

All of this is why it's insufficient to attempt to explain why the crossover settings posted by the OP sound good or don't sound good. There simply isn't enough information.

There is a good rule of thumb for at least avoiding the really ulglies--that is to avoid having speakers close to 180 degrees out of phase anywhere. THAT creates problems. Any other amount is less problematic..
__________________________________________________ ____________

Andy Wehmeyer :
Considering off axis response in the design of a speaker system is definitely not a myth, but insisting that the off axis response should be exactly the same as on axis response isn't the best design goal, especially in a car where MUCH of the sound we hear is reflected. 

The link below is a good place to start, although it isn't an explanation of what happens in a car.

Harman - Scientific Publications Publications

In a car it's sufficient to design a speaker system that won't have any obvious holes or peaks in the response due to drastically different speaker directivity at crossover points and then to equalize the response at the listening position (essentially the power response) so that it has some substantial bass boost, which is necessary in small rooms, and a high frequency response that falls gradually from about 1k up to 20k. With the exception of the bass boost, this curve looks like the power response of a speaker designed to sound good in rooms. 

It's the directivity index that describes this loudspeaker parameter. There's a much more in-depth explanation in Floyd Toole's recent book, "Sound Reproduction". 
__________________________________________________ ____________

Andy Wehmeyer :
The word "mirrors" is a bad one to use in this discussion. IF the off axis response is the same as the on axis response, and the on axis response is flat, the speaker will sound too bright. The on axis response should be flat and the off axis response should taper downward with increasing frequency. 

It isn't possible using current loudspeakers in existence without proprietary DSP filtering to build a speaker that has the same on-axis response as off axis response anyway. Fortunately, that isn't necessary. 

This thread has digressed into the realm of myth. If you want the facts. Read a book. I've posted the title of a good one that's written so most of you can understand it and it's available on Amazon. 

Or, continue to read and post a bunch of IMO or even IMHO posts that simply steer people in the wrong direction based on a bunch of guesses and half-baked "proofs". 

The world isn't flat, even though you may not have ever noticed the curve of the horizon


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## Tendean17

Andy Wehmeyer :
My point is that I posted a link to a very simple powerpoint presentation prepared by one of the world's premier acousticians that explains the concept of directivity, which is what we're talking about here. I also posted the title of a book that includes a very detailed explanation written by the same acoustician. I also posted a brief synopsis of the information in my own words as it pertains to cars. VP Electricity also posted the same information in somewhat more detailed form. 

There are some basic truths here that have been proven and have been long accepted as good science. Since I have access to plenty of documents and plenty of the scientists who do this work, I thought I'd provide access to some of it here. My insistence that good research performed by qualified scientists is similar to truth isn't telling people to F-off. 

If you use a system of speakers that is designed, along with it's crossover (passive or active) to provide flat response when measured on-axis, but you don't take into account the off axis response, you're asking for trouble. The dispersion of drivers narrows as the frequency rises and that's a function of the driver diameter (or radius). If you use a big midrange and a small tweeter and a crossover point that's within the range where the midrange's dispersion is narrow, you may have a flat on-axis response, but there will be a hole in the off axis response. The tweeter's dispersion will be wide at that frequency, so the off axis response of the tweeter will be louder in that region. That's what makes the hole a hole and not a gradual rolling-off at high frequencies. There's a picture of this in the book and also a graph in the powerpoint. 

Now, put that system in a car and you'll hear the on-axis response if the speakers are mounted on-axis. The off axis response will be reflected and will eventually make it to your ears, combined with the on-axis response. You'll hear the hole. 

Now, if you mount the speakers off axis, you'll hear the off axis response as the primary sound and the on-axis sound will be reflected off of all the surfaces and will eventually make it to your ears. It will be combined with the direct off-axis response and you'll still hear the hole.

The difference between cars and rooms is that the reflective surfaces are much closer--and, as you've pointed out--are probably more reflective at VERY high frequencies than a room because the glass is smoother than the sheetrock (not that much smoother, though). Since the reflective surfaces are much closer in cars than in rooms, the magnitude (loudness) of the reflections is greater--the inverse square rule describes this condition--sound intensity is reduced by 6dB for every doubling of distance. 

Because the reflective surfaces are much closer and the reflections are louder, the off axis response is more important in the car than in a room. Wait, maybe I should repeat that...

Because the reflective surfaces are much closer and the reflections are louder, the off axis response is more important in the car than in a room. 

The reflective surfaces in the car are irregular, unlike the walls in the room. Cavities have resonance and those resonances contribute the the reflected sound, just like the simple reflections from the rest of the surfaces. These modify the reflected sound. 

One could aask, "Wow, with all of those reflections, how could you even begin to predict what the car will actually sound like?" That would be a good question. Fortunately, because all of the reflections arrive at your ears at nearly the same time as the initial sound, we can eliminate one source of the problem by ensuring that there are no BIG PEAKS OR HOLES in the off axis response and that the off axis response of the speakers tapers down smoothly, so the system doesn't sound too bright. (If this is what TSpence means when he writes "mirrors" then we're on the same page and he gets it). Then, we can EQ the whole thing, direct and reflected sound according to a desired target response at the listening position. The irregularities in the reflected sound will still exist. 

If you want to change the shapes of the interior panels to eliminate some of them, that's some additional work that may be beneficial, but if you do it by conjecture and trial and error, it's very expensive and time consuming and you may end up with something that can't be driven. Plenty of IASCA competitors love to talk about how they remove the steering wheel to eliminate a reflection, but I've never talked to on who could tell me at what frequency the reflection caused a problem and why--they tell the judge this and the judge scratches his head and gives away a point.

It's important to remember that for measurement's sake, on-axis usually means "directly in front of the speaker". When you mount the speakers in your car, you can choose to mount them in a way that the measured on-axis response is directed at you or directed away from you. In either case, wht you hear in the car is the sum of all of the sound radiated from the speaker and reflected toward your ears. The reflected sound is a big contributor. With a speaker designed as I've described above (flat on axis and a gentle downward taper at higher frequencies), aiming the speaker away from the listening position removes high frequency from the response you hear. If it isn't designed as I've described above, but has a reasonably flat on-axis response and big holes and peaks in the off axis response, then mounting it so it doesn't point at you adds the irregular response to the sound you hear and attenuates the flat response from the sound you hear. Is this better? Maybe, if you're lucky enough to have a speaker system with holes where your car provides peaks and peaks where your car provides holes. 

It isn't credible to suggest that for all applications and all cars, it's best to point them away, because in many applications those peaks and holes don't cancel each other. Suggesting that will steer more people away from success than toward it. 

Designing a speaker system with it's crossover to provide the correct response in a particular car is a much more precise exercise than what is being espoused here when people posit that choosing a speaker with "bad off axis response" is better because IASCA winners do it or because "I heard a car that had those "SilkyPristineAudio" speakers in it and the curve in the brochure looks good, so the entire system design and whatever EQ is in the car doesn't matter because I like to simplify. Curve in brochure = good. Car sound = good. Brochure = truth = science = plausible and complete explanation." 

I have speakers mounted so that they fire into the glass and yes, the reflection causes a hole in the sum of the direct sound and the reflection. Is it a problem? Well...I was able to fix the frequency response well enough with an EQ. The benefit of the location is that the vocals and center information is precisely located where it should be.
__________________________________________________ ____________

Andy Wehmeyer :
Please don't make the mistake of thinking that IASCA, MECA or USACi judges have any idea what real music in real spaces sounds like. Because of the confines of the car, perfectly replacing the car's acoustic space with a larger one is only possible for one seating position and one head position if the processor has enough to power to make some really long calculations really quickly. That's coming one day. For now, our best hope is to add the sound of the larger space to the smaller one. 

A careful reading of Jeff's post and the link and some thinking will reveal something very important--the dimensions of the car are too small to matter much, once we add the sound of the larger room--we hear the car as the initial sound and the delayed signal (provided it's 20mS or later) as ambience. 

The key thing to remember is that the sound of the rear speakers has to be decorrelated from the front. It can't be unprocessed stereo. That's not rear fill, that's rear speakers. The difference signal and the delay help to do that. Providing a front stage that's really wider than the speaker locations requires some additional processing not available for cars yet. 

I've competed for the past few years just so I can fight with judges. I love it when they say, "Wow, the stage is deep and the ambience is really cool. The images are well focused and the center image is rock solid. I've never heard anything like that. The only problem is that when I turn my head to the side, I hear something coming from the back. Do you have rear speakers? If you do, you should take them out or turn them off."

To that, I usually reply, "Ever listen to music on something besides a 2-channel system in your living room?"

They usually reply, "I don't have a home system, but my car won IASCA in 1997." 

I often reply, "That was 1997. There are more and better tools available today and as a manufacturer of those tools, I'd like to be able to sell them to consumers who want their cars to sound better and who have no interest in fiberglas kick panels, rebuilt dashboards and stilts on their shoes to reach the pedals."

A friend of mine in Italy refers to car audio 2-channelers as the "Car Audio Taliban". 

Modernize, folks!


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## Tendean17

Andy Wehmeyer :
I've heard a couple of cars in which the installer believed he had done this--in fact, he must have because the car sounded lifeless to me--sounded like a huge pair of 15" headphones. Those cars did other things well, but those areas of performance were unrelated to this. I think it's a waste of time and I don't really like the sound of "dead" rooms, especially with 2-channel set-ups. Multi-channel setups make this less necessary, since the sides and rears can be used to add the reflections of a different space. 

This is also explained in great detail in Floyd's book. I really suggest that those of you who are serously interested in this stuff buy it and use it as a reference. It'll save you lots of time, lots of money and you'll have a thousand head-slapping--"no ****...that's why that happens" moments while you read it.

I wish I had been a serious competitor in the 90s so I could have plunked down some cash for "teardowns" of some of the most famous cars. You wouldn't believe the ********. Some of it is the cause of all this consternation over speaker placement, reflections, optical signal connections, etc.
__________________________________________________ ____________

Andy Wehmeyer :
Hey Patrick, It has and can be done with DSP--and a very specific arrangement of speakers. Here's a link to the explanation. I've heard this and it's amazing. 

http://www.xlrtechs.com/dbkeele.com/...20Part 2.pdf

BTW, Dr. Horbach is our principal DSP engineer and MS-8 is a result of some of his other work.


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## Tendean17

Andy Wehmeyer :
Because these reflections all happen very soon after the initial sound, they sound like frequency response anomalies--peaks and dips in the response. The early ones spread the apparent source and the ones toward the end help us determine that we're in a small space. The reflection from the left speaker off a boundary on the right that arrives at our right ear and vice versa is crosstalk. That crosstalk narrows the image and degrades the stereo reproduction a little bit. 

In a big room or a concert hall, the walls are farther away and the reflections arrive at our ears much later and with reduced intensity. many of them sound like separate events--that's reverberation. We can make the space in the car seem larger by ADDING late reflections and some additional early ones. Trying to get rid of the ones that are there is a waste of time. As Patrick has discovered, the size of horns that are required to narrow the dispersion enough to make a difference is prohibitive in a car.

Reflections are how we determine the size of the space we're in. Listening to speakers in an anechoic chamber is horrible--the most unnatural sounding thing you've ever heard.

Lycan :
I largely agree, but a few points are worth emphasizing :

1. Very near, close-in-time reflections will NOT be distinguished from the original sound (the Haas limit determines how close is "close"). They will impact frequency response (via comb filtering) and localize-ability ... mostly, never in a "good" way: stereo reproduction, from recording through expected playback, does not "depend on" nor "anticipate" these reflections in any way. There are a few exceptions, where near reflections aren't a terrible thing, including : ultra-close reflections, such that the first comb null is outside the driver's pass band (categories include corner-loading subs, and midranges on dash very close to windshield), and deliberately depending, primarily, on a tweeter reflection, while minimizing that tweeter's primary radiation to the ear.

2. Later-in-time reflections do indeed give us a sense of "space". The mind can distinguish these (even if just barely) from the original event. This category was the whole basis for "intelligent rear fill" ... bandlimited, delayed, L-R difference signal. Done properly, this technique will give you a larger sense of space, sounding like you're listening in a larger-than-shoebox venue.

3. Very late reflections sound like reverb or echo ... mostly to be avoided

Andy Wehmeyer :
3. Very late reflections sound like reverb or echo ... mostly to be avoided.

Avoiding these in a car isn't too difficult. there's no possbility thatyou could mount a speaker far enough away to generate these and no reflective surface is far enough away to provide them.

I find, though, that adding some that are synthesized by a DSP can have a really pleasant effect and can dramatically increase the sense of space, but they don't extend the width of the instrument placement. Early reflections (like ones you'd hear from the wall behind and beside the musicians) can also be added in the same way and also have a pleasing effect.

If you're in LA, I'd be happy to give you a demo, but I think this may be the only place to hear this. My car includes some custom DSP that does this, but I've never heard another car that includes it


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## Tendean17

Andy Wehmeyer :
1. Acoustic crosstalk is the enemy of "width"
2. Cars are acoustic crosstalk nightmares because all of the boundaries are so close that the reflections are heard as part of the primary signal and the reflections that kill width most effectively are the ones off the near side glass (from the far side speaker) and the ones off the front windshield. Basically, you have a right speaker mounted on the right and you hear it in your left ear too (off the near side glass) and you hear the speakers off the windshield too.. 
3. Ambio rigs have one main objective--eliminating acoustic crosstalk. 
4. Headphones have no acoustic crosstalk, but the setup eliminates our ability to determine the location of sound in any plane except one--left and right--because it doesn't allow the shapes of our heads or ears to be used as location cues for front or rear and doesn't allow us to move our heads to change ITD to determine location either. For 3-D headphones, a head tracker and a serious DSP that imparts binaural filters and room reflections fix this. 

So, Floyd's book illustrates perfectly what makes apparent width in a room--the primary reflection from a side wall. A perfect reflection from a side wall would be like having an additional speaker located outside that wall at a distance that corresponds to the length of the reflection. If the reflection was the same amplitude and the same frequency response and in phase with the sound of the speaker, the image would appear at a midpoint between the speaker and the apparent location of the "phantom" speaker, just as a center image is formed between the left and right speakers for a mono signal. There's an illustration in the book that makes this really easy to understand. 

I've read plenty of posts here and in other forums about people attempting to exploit this using the side glass. Does it work? Well, sort of. There isn't much width enhancement because the side glass is so close, but you can get a little. The big problem with this is that it's difficult to reflect the ENTIRE spectrum off the glass because of the location of the midrange and tweeters. 

So, while the reflection off the side glass can be helpful, the reflection off the windshield does the opposite--it narrows the stage. Hanging mids and tweeters in the a-pillars works at really high frequencies because the high frequencies are radiated into forward angles and less into rearward angles. At lower frequencies where the speaker radiates into all angles the reflection off the windshield and the side glass basically cancel each other and the left and right images in the midrange frequencies are just big. Floyd writes about this too and the term he uses is 'image spread", I think. The BS widebander in the a-pillar approach is effective at high frequencies only, makes the situation much worse in the midrange and lower frequencies and has other serious drawbacks that, in my opinion, make them a sham. I heard a car in Jakarta one day where the tweeters and mids in the a-pillars were mounted on some BIG baffles. This was pretty effective, but I couldn't have driven the car safely and especially not in Jakarta traffic!

So, if we know that we can exploit the reflection off the side glass (sort of) and no matter what we do, every source on the right will also be heard on the left because of acoustic crosstalk in our little reflective car interior, this all seems like a game of whack-a-mole and that's apparent in listening to cars whose owners claim to have "a stage that extends outside the boundaries of the car". I always find that there are one or two tracks that these guys play to prove this. Usually, those tracks include some sound or event that really does seem to happen outside the car. The stupid pink panther track on the IASCA disc is perfect for this. It's really easy to get the triangle to sound like it comes from outside the car. I use the track from the EMEA disc where the guy walks across the stage. It works perfectly in my car because I have a DSP algorithm that synthesizes a room and with the settings just right, I can make it seem to synthesize the room in the recording. With that track, I can get the guy to sound like he's 10 feet to the right and left of the car and 10 feet in front of the hood. Does it work on all tracks? Of course not. It's way more impressive than the Pink Panther's triangle, though. For many recordings, I have a car that makes it seem that the room is bigger than the car. 

The second hint is Chad's suggestion about L-R. An old recording technique is to maximize width by recording left sounds out of phase and at a lower level in the right, and vice versa. Upmixers like L7 and DolbyPL2 steer these sounds to the rear. In L7, the rears and sides are stereo and also steer left and right based on relative level. So...

Carefully placed left and right rear speakers will place these sounds in another pair of locations which, properly delayed and at the right level, can create a phantom image for those sounds in a location that is "between" the left front and left rear speakers (and the same for the right). Since the shape of our ears and our heads are primarily how we determine the front to rear locations of sounds, we can make the sound of the rear speakers more difficult to locate by attenuating the frequencies at which we do that--high frequencies. Then, if we close our eyes and make a wish, we can convince ourselves a little more easily that sounds come from outside the car.

The effects of all of these are seriously diminished in a car because of the acoustic crosstalk. You can eliminate a bunch of reflections (as Mark E. did in his 4-runner) to improve this a little bit, but the killer reflections are the ones from the side windows and the door glass and can't be eliminated in cars that are driven on the street. We have to be able to see. However, the rear speakers are far away from the windshield..that's good and in my experience, this is the place to start. 

OK...there are some more hints.


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## Tendean17

Patrick Bateman :
_If you REALLY want to hear the recording, this is probably 'the hot ticket.' Be prepared to get disappointed though - there really isn't much of a soundstage on your recordings. A lot of the 'tricks' we've been hearing in our car are our own creation. It's fake soundstaging._

Andy Wehmeyer :
This is absolutely true and the reason I'll take believability over accuracy any day. My DSP includes room synthesis. Does it recreate a room? Well, no, because I'm in a car and my experience is subject to all of those reflections that define the space in which I listen. Does it make listening much more fun and does it sound more natural and less bound by the car. Yes. Do I give two ****s about what's on the CD? Well...no. Have I won and IASCA contest or two by duping the judges into thinking that the ambience created by my DSP is really on the recording and not reproduced by other cars? Yes. Does that matter? Not to them, I didn't tell them that the ambience they loved was "fake". It mattered to me because it made me laugh.

Thanks Patrick.
__________________________________________________ ____________

Thehatedguy :
_One mid moved to the upper door from the pillars...big big difference. Working on the other side this weekend.
I would listen to everything Andy says to do. Every time I do what he says, my MS-8 experience gets better and better_

Andy Wehmeyer :
Thanks. Once again, this is why I still show up at work.


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## Tendean17

From other forum www.audiogroupforum.com

Andy Wehmeyer :
The explanation of effects of "tweeter toe-in" is pretty straightforward:

1. Compared to a speaker's response on axis, high frequencies are attenuated as one moves off axis.
2. The measured amplitude of a speaker (unless it's a line source) is -6dB for every doubling of distance away.
3. With tweeters on axis in the A-Pillar, the tweeter nearest the listener sounds louder than the tweeter in the opposite pillar because of #2 above.
4.The frequency where the attenuation begins is a function of the diameter of the dome (bigger dome = lower frequency) and reflections from nearby surfaces.

So...if I sit in the driver's seat and the tweeter on the driver's side sounds louder, I can attenuate it for my position by turning it off-axis. Since it will still be on-axis (or close) for the listener in the passenger's seat, the level that listener hears is nearly unchanged. Now at each listening position, the levels of the two tweeters are more similar.

For a little 1" dome, the frequency where that attenuation begins is pretty high (see loudspeaker design cookbook or others) and that's why people say to cross the a-pillar tweeter over at 10k or thereabouts. If you cross them over much lower, the attenuation "trick" doesn't work at low frequencies and it screws up the image
__________________________________________________ ____________

Mark Eldridge :
Congratulations on the wins in Texas. There are some really good cars that compete in that area. 

Speaker placement, along with controling reflections and the speakers' dispersion patterns are definitely critical aspects of ataining good stage width. If your high frequency drivers are on top of the dash, they are likely mounted inside the A-pillars. You're also likely getting a very strong early reflection off the windshield that arrives within a millisecond of the direct sound from the speakers. These two conditions will make it very difficult to create an aural illusion of the stage being much wider than where the speakers are placed, regardless of how much signal processing you throw in the mix. 

Barring a pretty substantial rebuild of the front stage configuration, you can try placing a thick piece of foam just above the speakers on the windshield to reduce the reflection energy. Other than that, there aren't too many techniques that will be very effective. 

Good luck! If it gets to a point that you can't get the system working better with what you've got, and you want to look at some reconfiguration ideas, let us know
__________________________________________________ ____________

Mark Eldridge :
Hmmm... path length differences... You might as well get that signal alignment device cause I'm not going to help you... Yea, right!

Actually, I'd recommend looking for past threads on the topic, in addition to what we discuss here. There have been a lot of threads on this subject in the last year or two, and you can find them in the archives and just by searching for threads on path lengths, imaging, staging, etc. Also, buy a copy of the Autosound 2000 Tech Briefs, and read tha articles in that collection. Between those two sources, you'll have more information than you can probably find form all other sources combined. 
The real skivvy is that you want to minimize the differences, for a lot of reasons. Especially in the mid-bass through the midrange regions, the difference between left and right pathlengths is CRITICAL! In fact, between 100 and 400 Hz, the angle of the speaker won't even matter, as imaging cues are almost 100% determined by path length, not by intensity differences. Above 2000 Hz, imaging cues can be controlled by speaker angle and other intensity controlling techniques. Path lengths above 2000 Hz are not critical. 

As far as the path length differences between the mid-bass driver, midrange, adn tweeter on a single side, you'll probably never get them exactly the same. The real problems with path length differences here will be in the frequency and phase response in the crossover range. Signal alignment can help some here, as long as the speakers aren't too far from each other. It's more acceptable to have a mid-bass amd midrange separated than to separate the mid and tweeter. The mid-bass frequency range can make a difference in the perceived stage depth,and the center image stability. But, the upper midrange and high frequencies are responsible for the stage height, width, and depth, as well as image focus. Keeping these frequency range drivers close together will be a lot easier to control all the variables than separating them. If you need additional stage height because the mid and tweeter are in the kick panel area, then add a second set of tweeters high and wide, and crossed over pretty high as well (somewhere between 8000 and 20000 Hz). This configuration is what has been used in most all fo the best sounding cars that use conventional drivers. And in most of the HLCD systems, the additional tweeters are used for the same reason. 

Anyway, locate the midrange drivers first, and work with them in their intended frequency range to achieve the best overall stage depth and center image. Don't worry too much about stage height or width yet.

Next, locate the mid-bass drivers so they blend well with the mids, have solid output, and do not detract from the center image. Doors will likely not be the best place for them. They can be mounted under the dash, in the floor, in the firewall towards the center of the car from the kick panel, or where ever else they work, and can have a large enough enclosure.

The tweeters are the easiest. Mount them as close to the mids as possible, and make sure they give you the width and height you want, and help to focus the image performance. If you need the additional height, add the second set of tweeters.

Path lengths are a different animal. They're kind of like the impedance of a woofer. Industry wide, we call a speaker a "4 ohm" or "2 ohm" speaker, when in reality, it is only really that impedance at one or maybe two frequencies. That's the "nominal" impedance which means "in name only." The actual impedance varies widely accoring to frequency. A "4 ohm" speaker in a box may have impedances as high as 50 ohms at resonance, and as low as 3 ohms elsewhere.

Likewise, the sonic cues that affect what we percieve as staging and imaging are frequency dependent, and there is no one single number, technique, or what ever that can be used across the frequency board.

Good luck!


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## Tendean17

Andy Wehmeyer :
Don't forget that a woofer crossed over at 80Hz plays plenty of information above that depending on the crossover slope. More importantly, second and third order harmonic distortion plays a huge part in helping the listener localize the sound of the bass. Some woofers for cars make plenty of second and third order distortion.

You can filter that out acoustically with a bandpass box (built correctly, but you can't do it electronically with simple low pass filters.
__________________________________________________ ____________

Andy Wehmeyer :
Enclosing a speaker affects the low frquency roll off, unless the box causes a peak in the response above roll off. A sealed box that's too small will do that and a vented box that's too small, tuned too high or both will also do that. There's another thing we commonly use in cars that does the same thing--a CROSSOVER (high pass filter). If you'll use a high-pass filter on the midbass drivers, there's no need to enclose them because you can apply the high pass filter for the ame effect

The correct answer is that if you're using a crossover, there's not going to be a big difference between IB or sealed except for a sealed box that's so small that it minimizes the low frequency extension AND puts a huge peak in the response of the driver. Then, you will have used the box as the filter and the crossover will only limit the power that goes to the speaker. My point is that you can affect the output of the speaker with a filter in the same way you can with a box, but adjusting the filter is easier than adjusting the box. 
__________________________________________________ ____________

Mark Eldridge :
Speaker placement is always the first,and most important part of designing a great sounding system. If you want to (or have to because of time/financial requirements) you can use factory locations. But even if you only care about the driver's seat listening location, I'd bet you can make a significant improvement in the system SQ by working on the speaker placement.

Andy's car is one of the best sounding systems I've ever heard using almost factory locations. He has spent a ton of time with the Harman processor to make it sound as good as it does. IT does some things like no other system I've heard, and other things that are average, and many in between. He didn't want to spend the time and money, not to mention he didn't want to tear up the Mini, to place the speakers other than in the doors. That's great, and I whole-heartedly agree. I wouldn't cut that car either. 

But, it is limited in some areas that could be improved by mechanically relocating the speakers. That's the trade off. Cut the car, and make it better, or don't cut it, and accept the trade offs. Sometimes, only a little modification work can go a long way to improving the acoustical properties of the car. 

Making a car sound good from only one seat is really easy compared to making it sound equally good from both seats. For one seat, the signal delay can help, but you sacrifice the other seat every time. 

The real challenge is in taking the time to learn about sound, how to control it, and make it sound great from both seats. 

BTW, if you get the chance, listen to the room effect in Andy's car... Unbelievable !!! 
__________________________________________________ ____________

Mark Eldridge :
Do you have any room for a midbass enclosure in the bottom of the dash assembly, above your feet? 

Midbass is not very critical for stage width or height, but is essential for depth. Also, if the pathlength difference is too large, say over 6 inches for the midbass range from 100 to 400 Hz, the imaging will be shifted to the close side. 

Mounting them under the dash will help with equalizing path lengths, and leave the kick panel area for the mids, which will have a strong influence on width.

Tweeters mounted only in the pillars... I'd put them next to the mids, maybe mounted just above, or in front of them, or where ever you get the best staging properties. Mounting them so far away from the mid up in the pillar can cause problems with creating a coherent wave front, and possibly comb filtering. The results can be phase related problems causing depth, height, and imaging problems. 

In every case I have worked on in a serious SQ competition car, I have found that placing the primary tweeter as close to the mid as possible yields the best results. With them close together, it is much easier to achieve a coherent wave front from both channels, and minimize comb filtering. The staging and imaging will be much more stable, and easier to tune. If after tweaking the system with this configuration you find that height and width might be improved, you can add a secondary tweeter in the pillar, turned down, and crossed over somewhere above 8,000 Hz, only enough to bring up the corners of the stage, and add some width.

Not necessarily. Sure, if your feet feel the air movement, your perception of the stage will be affected. But in many cases, when done well, midbass drivers mounted in that area work great.

If you have a solid midrange and high frequency stage with good perceived stage height, locating the midbass lower will not affect it. 

Comb filtering is a result of the same sound arriving at a point like your ear or a microphone tip, but at two different times. For example, a midrange and tweeter mounted on the dash top pointed at the windshield will result in your ears hearing the direct sound from the speaker, followed a fraction of a milisecond by the reflection of the sound off of the windshield. You get essentially the same sound twice at two different times. The phase differences in the arrival sounds will combine either destructively, or constructively, depending on the frequency and the additional distance/time the reflected sound incurs before arriving at your ear. The result can be some very wildly variating frequency response. 

Try sitting in front of a single home seaker with no hard surfaces near you or the speaker. Listen to a song you are familiar with. Then have someone hold a board, large mirror, or some other hard surface so that it creates a reflection that arrives at your ear also. That is comb filtering


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## Tendean17

New Update from post 79 - 115.

*JBL MS-8 FAQ – Index Number* 

View Single post -> Then click link : "JBL MS-8 FAQ" in the right corner to display with starting list.

*• About JBL MS-8* 

Start Post No. 1 : (Post No.03) -> http://www.diymobileaudio.com/forum/1236157-post3.html
Start Post No. 2 : (Post No.70) -> http://www.diymobileaudio.com/forum/1237889-post70.html
Start Post No. 3 : (Post No.80) -> http://www.diymobileaudio.com/forum/1489198-post80.html

*• Prepare your system design first *

Start Post No. 1 : (Post No. 16) -> http://www.diymobileaudio.com/forum/1236171-post16.html
Start Post No. 2 : (Post No. 92) -> http://www.diymobileaudio.com/forum/1489220-post92.html

*• Target Curve for JBL MS-8 *

Start Post No. 1 : (Post No. 21) -> http://www.diymobileaudio.com/forum/1236176-post21.html

*• Phase Frequency Response *

Start Post No. 1 : (Post No. 25) -> http://www.diymobileaudio.com/forum/1236180-post25.html

*• Center and Rear Channel* 

Start Post No. 1 : (Post No. 27) -> http://www.diymobileaudio.com/forum/1236182-post27.html
Start Post No. 2 : (Post No. 71) -> http://www.diymobileaudio.com/forum/1237896-post71.html

*• Aux Input, Signal Level and Preout Voltage *

Start Post No. 1 : (Post No. 33) -> http://www.diymobileaudio.com/forum/1236190-post33.html

*• Measurement and Setup *

Start Post No. 1 : (Post No. 41) -> http://www.diymobileaudio.com/forum/1236198-post41.html
Start Post No. 2 : (Post No. 85) -> http://www.diymobileaudio.com/forum/1489205-post85.html

*• System Noise *

Start Post No. 1 : (Post No. 57) -> http://www.diymobileaudio.com/forum/1236218-post57.html

*• Happy Customer *

Start Post No. 1 : (Post No. 58) -> http://www.diymobileaudio.com/forum/1236220-post58.html

*• Feature Request*

Start Post No. 1 : (Post No. 59) -> http://www.diymobileaudio.com/forum/1236221-post59.html


Thanks for reading ... and Hopefully useful. 
.


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## Neil_J

Tendean17 said:


> Andy Wehmeyer :
> Hey Patrick, It has and can be done with DSP--and a very specific arrangement of speakers. Here's a link to the explanation. I've heard this and it's amazing.
> 
> http://www.xlrtechs.com/dbkeele.com/...20Part 2.pdf
> 
> BTW, Dr. Horbach is our principal DSP engineer and MS-8 is a result of some of his other work.


Link is broken -- It should be: http://www.xlrtechs.com/dbkeele.com/PDF/Keele%20(2007-09%20AES%20Preprint)-%20Linear%20Phase%20Digital%20Crossover%20Flters%20Part%202.pdf


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## rytekproject

bumping good info


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## bgcontract

Hi, I just bought an MS-8 and pretty excited about it. I know all my crossover points/slopes, channel assignment etc. I just have a few basic questions to be sure of.

I want to go active and power my mid woofer and tweeter separately. Currently, I have a passive crossover that is powered by a PDX-4 (100 RMS per channel). I have Focal KRX2 woofer/tweeter components.

So I am feeding each woofer/tweeter passive crossover 100 watts each (and powering a my rear co-axials the other 2 channels of 100w/each side. 

My first question is: Do passive crossovers reduce power (wattage) being supplied to the tweeter when it "splits" the high freq. signal from the low freg. signal ? 

My guess is "yes" because I looked up the power specs for my Focal TN53K tweeters and they are rated at 15w nominal and 100 max. So the crossover must be reducing power right? 

My 2nd question is: If the tweeters are rated at 15w nominal will running them at 20w nominal be too much(or too little???) for these tweeters? I plan on using the JBL MS-8 to power the tweeters and the onboard amp is rated at a 20w RMS. 

In the end, I will be powering all 4 mid-range speakers (front and rear) with my PDX-4 and power the tweeters using the onboard amp on the MS-8 and not sure if using the onboard amp is the right way to go (for the tweeters).

Thanks in advance for any help!!


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## slinger1

I split my front comps. but kept the xover on the tweets....


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## Lord Raven

Awesome... Subscribed..!


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## talan7

I have a 2012 Buick Regal GS with the Harmon Kardon system. My wife gave me the JBL MS-A5001 subwoofer amp for Christmas. I was thinking of getting the MS-8 and revamping my system. 
My question is, how would the MS-8 improve my current setup? The HK system I have now has pleasing sound but I'd like it to play louder. Is the stock HK amp similar to the MS8.the MS-8 have more power? Does I want to be sure that upon installing the MS-8 I will be more pleased than with what I have now. One shop told me just to install the subwoofer amp and sub. I'd like to go into my car once and be done with it.


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## 14642

If you like the way it sounds and just want more volume, just add amps. The MS-A1004 is designed to do this. Just use the speaker level inputs.


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## SO20thCentury

EXCELLENT reference Mr. Tendean17! Thank you for taking the time to compile this! You have here answers to not only probably all MS-8 related questions but a concise FAQ catalog to the whys and hows of car audio. This should be stickied and kept from being polluted by more questions that are likely to be already answered here. And thanks to all of those who's experience was shared here most notably Andy Wehmeyer. I hope I've correctly peeled the orange and will soon clearly see on the creamed corn can the green giant's magic wand.


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## Schnathorst

Here's my current system:
2003 Tahoe
Alternator: DC Power 250amp max / 180amp idle
Battery: Optima combo high crank / deep cell
Big 3 upgrade with 0awg
H/U: Kenwood DDX-771
Main Amp: Rockford Fosgate P600X4
Sub Amp: JL Audio XD 600/V2
Fronts: JL Audio C3-600's, Component Config, with passive XO's in doors
Rears: JL Audio C3-600's, Coaxial Config, with passive XO's in doors
Sub: JL Audio HO110-w6v3

I'm still fine tuning the install by improving the sound dampening on the doors and I'm also considering buying an MS-8 to improve my sound stage. Since I'm running all of the C3-600's through passives for the mids and tweets, will this diminish the capabilities of the MS-8? Would it be better to use the MS-8 amp to power the tweets and the main amp to power the mids?

Thanks,
SS


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## evhudsons

I'd like to know too. I had been using my passives in addition to the ms8 with my focal 3 ways. My opinion was that I had better sound with the passives, but I have read that passives could be skipped and use the ms8 so I may have been doing something wrong. my ms8 got a short and so this month I had to tweak the head unit and learned a few things, so I think I didn't have everything set up right for the ms8 to sound it's best. For instance I had not used a multimeter to set the gains on my amps. That made a huge difference, like, realllly big difference. I'm waiting on my new ms8 now and want to have it set up right and was wondering if I should use the passive crossovers.


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## Elgrosso

Schnathorst said:


> Would it be better to use the MS-8 amp to power the tweets and the main amp to power the mids?
> 
> Thanks,
> SS


Sure, but it also depends of your need. You want it tuned for 1/2/4 seats?


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## talan7

evhudsons said:


> I'd like to know too. I had been using my passives in addition to the ms8 with my focal 3 ways. My opinion was that I had better sound with the passives, but I have read that passives could be skipped and use the ms8 so I may have been doing something wrong. my ms8 got a short and so this month I had to tweak the head unit and learned a few things, so I think I didn't have everything set up right for the ms8 to sound it's best. For instance I had not used a multimeter to set the gains on my amps. That made a huge difference, like, realllly big difference. I'm waiting on my new ms8 now and want to have it set up right and was wondering if I should use the passive crossovers.


Exactly how do you use a multimeter to set gains on amp? Do you disconnect the ms8 from the amp to do that? I've been using passives on my front components and I think that's the problem. My tweeters are loud but my woofers aren't loud at all so when I calibrate I have issues. I plan on getting new speakers and running active and expect better results.


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## Schnathorst

One seat... driver seat, with a focus on center stage.


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## Elgrosso

So I'd say something like:
Ms8 channels 1,2 > front tweeters
3,4 > amp 1 > front mids
5,6 > amp 1 > rear XO > mid/tweet
7 > amp 2 > sub

Or

1,2 > front tweeters
3,4 > amp 1 > FR mids
5,6 > rear tweeters
7,8 > amp 1 > rear mids
Sub amp plugged on amp 1 pass-through from Front
(if you can define this the amp)

But maybe we should keep this thread clean and use the gigantic ms8 one?


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## Schnathorst

Thanks Elgro! I like this idea:

Ms8 channels 1,2 > front tweeters
3,4 > amp 1 > front mids
5,6 > amp 1 > rear XO > mid/tweet
7 > amp 2 > sub

Eventually, when I have more money, I plan to go with this configuration:
Ms8 channels 1,2 > front tweeters in kick pods (not door)
3,4 > amp 1 > front mids full range in kick pods (not door)
5,6 > amp 1 > front 6.5 mid woofer in door (drop rear fill)
7 > amp 2 > sub

So your recommendation would set me up nicely for a future conversion.

SS


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## Elgrosso

You're welcome, but rear fill is really cool with the ms8 (Logic7)
2nd solution could also allow 3 way + rear (XO) + sub


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## Schnathorst

Big news! I purchased the MS-8 last night, should be here by the weekend. I'm going to start with a unique configuration to see how it works. Specifically, I'm going to go with this config:

Ms8 channels 1,2 > stock front tweeters on A pillars (hopefully lift sound stage a little)
3,4 > amp 1 > front XO > mid/tweet (in front doors)
5,6 > amp 1 > rear XO > mid/tweet (in rear doors)
7 > amp 2 > sub

If the stock tweets aren't upto the level of quality I like then I'll go with this config:

Ms8 channels 1,2 > front tweeters
3,4 > amp 1 > front mids
5,6 > amp 1 > rear XO > mid/tweet
7 > amp 2 > sub

Thanks again for all the help!

SS


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## Elgrosso

You really mean to use 4 tweeters in front? Crossed or playing the same range?


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## Schnathorst

Playing the same range. Still thinking this one through. I may simply start with out the factory tweets to see if the MS-8 lifts the soundstage on it's own.


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## maggie-g

please keep in mind this is the FAQ thread. There is a regular MS-8 thread to hlep keep track of the onsie twosie questions.


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## princ3cmo

> There's another condition that has been reported a couple of times, and that's a condition in which MS-8 reads "Signal Low" until the volume control of the head unit is increased to a certain point at which MS-8 reads "Signal None". This indicates that there is something non-linear ,that isn't clipping, that happens to the signal at that point. I haven't had an oppotunity to do any investigation, but this has happened in two Audis with the B&O DSP system.


Was this issue ever resolved? This is the problem I am having


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## IJCOBRA

I'm getting a lot of low level static noise out of my speakers with the MS-8. Didn't have it with the 3Sixty.3. I can even hear a low rumble through the subs with the bass knob all the way down. I can hear it through all speakers even with volume all the way down. It does not increase or decrease unless I turn the MS-8's volume down. Below -30dB it is inaudible. When I restore the MS-8 to factory defaults, during the reset the noise goes away and it's completely silent.

I auto tuned with the MS-8 at -40dB. I run it at -10.

MS-8 says it doesn't want my headunit above 35 (goes to 40). I set gains on my amps using 0dB test tones at 25 on headunit (~3/4 usable volume) and the MS-8 at -10dB. This allows me to go to 35 on the headunit for gain overlap if needed. I only use the headunit for volume control.

Amps are all JL Slash v1: 2 300/4, 1 450/4, 1 1000/1.

Channels:
1: FL HI (4" mid and tweeter crossed over through 300/4 amp)
2: FL LO (8" Midbass)
3: SL (4" coax in back)
4: SUB
5: FR HI
6: FR LO
7: SR
8: CTR (4" mid and tweeter crossed over through 300/4 amp)

Sounds good besides the hiss and rumble.

I suspect that if I set my gains with the MS-8 any lower (like at -30) I will not be able to adjust my amps up enough for max power.


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## DDfusion

I have a very low level hiss(fax machine) type sound at low volume. It goes away when the car warms up. I think ford wired the radio hot to the same spot the turbo is on.


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## Force

how to use EZ mode in setup of jbl ms8


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## Vx220

Old thread, I know, but I wanted to thank the OP for compiling it all, and everyone else for their contribution. 

Not sure if Andy W is still on here, but he needs thanking for his analogies! He probably needs a prod towards writing a book of them...


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## mzmtg

Just to dig up this old fossilized thread for us MS-8 faithful...

I've been running an MS-8 for a little over three years. I've been very happy with it in general. I did deal with some inconsistent results of the auto tune and issues getting consistent bass integration, but I could get it to sound like I wanted pretty easily.

I recently changed a couple of drivers in my system, so I needed to retune it. I had HUGE headaches this time. VERY inconsistent results and the bass was just never right.

So, I came back to this thread and started reading. 

One of Andy's posts jumped out at me and I gave it a try. 

I moved all my crossovers UP. I cross my 12" sub to my 6.5" midbass at 90 Hz. I cross the 6.5" to the 3.5" mids at 1K Hz.

It's AMAZING. The auto tune nailed it, first try. Perfect image, perfect bass. I can rerun and rerun the auto tune and it's the same every time. This WORKS for me.

Maybe it will work for you.


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## trunks9_us

mzmtg said:


> Just to dig up this old fossilized thread for us MS-8 faithful...
> 
> I've been running an MS-8 for a little over three years. I've been very happy with it in general. I did deal with some inconsistent results of the auto tune and issues getting consistent bass integration, but I could get it to sound like I wanted pretty easily.
> 
> I recently changed a couple of drivers in my system, so I needed to retune it. I had HUGE headaches this time. VERY inconsistent results and the bass was just never right.
> 
> So, I came back to this thread and started reading.
> 
> One of Andy's posts jumped out at me and I gave it a try.
> 
> I moved all my crossovers UP. I cross my 12" sub to my 6.5" midbass at 90 Hz. I cross the 6.5" to the 3.5" mids at 1K Hz.
> 
> It's AMAZING. The auto tune nailed it, first try. Perfect image, perfect bass. I can rerun and rerun the auto tune and it's the same every time. This WORKS for me.
> 
> Maybe it will work for you.


Care to link the page and part you are referring to since I just got a Ms8 never have used one i d like to get a tune worth getting done right the first time so any tips or walk through would be super helpful and no I have not read the manual yet but I will be shortly


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