# My budget tuning process



## mzmtg (Dec 8, 2009)

Here's where I've gone so far trying to make the best of what I have. I'm looking for any tips or constructive criticism.

My system is passive 6.5" components up front & a 12" sub in the back of the car. It's powered by a 4-channel MTX amp with the rear channel bridged to drive the sub. My headunit is a *Kenwood* that has all the tuning features of the midrange Kenwood & JVC units these days.

The main tools I use are:
13-band graphic EQ (range is +/- 9db per band)
Digital Time Alignment (distance & gain adjustment for each channel)
Crossovers ("Tweeter crossover" is actually an adjustable high pass shelf filter with frequency adjustment and seperate L & R gain)

I am not using any of the other adjustments like loudness, bass boost, subwoofer level control, "stage EQ", "sound realizer" and so on.

Install log is here: *http://www.diymobileaudio.com/forum...8690-2010-mazda-cx-9-touring-install-log.html*

I'm using the *Dayton IMM-6* calibrated mic in my Android phone and the *Audio Tool app* for measurements.

I'm generally following Andy W's approach he's been writing up on the AudioFrog Forum: *Time Alignment Part 5: Putting it all together* 

First, I set all my amp gains using an *o-scope* to watch for clipping. I used -10db sine tones, 1KHz for the front and 40Hz for the sub channel.

The passive crossovers cross my mids & tweeters about *4.8kHz* with a *12db* slope. My mids are high-passed at *80Hz* with a *24db* slope. My subwoofer is low-passed at *70Hz, 24db*.

Then I used Erin's site to set up my time alignment. Here are my measurements and the site's calculations:
Capture by ben.garner, on Flickr

From there, I tweaked the left and right side values to move the image more to the center using pink noise pops.

My final time alignment settings are:
Front Left: *3.73*ms
Front Right *2.8*ms
Subwoofer: *0.0*ms

Next I used uncorrelated pink noise & the Dayton mic to adjust the subwoofer gain down at the amplifier until it's volume at the driver's seat matched the front channels.

Setting the Audio Tool app to 1/3 Octave & playing the uncorrelated pink noise, here's my uncorrected response:
Screenshot_20180209-100710 by ben.garner, on Flickr

Then I used the headunit EQ to raise the bass level back up using the "Bass Extend" function. This turns the bottom EQ band (63Hz) setting into a shelf filter that raises or lowers all the frequencies below 63Hz. 

Again using the mic and uncorrelated pink noise, I adjusted the other EQ bands to minimize any peaks that I could. I also used the the head unit "tweeter crossover" to bring down everything above 4kHz just a tiny bit.

My EQ settings so far (all filters have a Q of 1.35):
20-63 Hz: +9
100 Hz: +4
160 Hz: -8
250 Hz: -7
400 Hz: +6
630 Hz: -3
1 kHz: 0
1.6 kHz: -6
2.5 kHz: -3
4 kHz: -2
6.3 kHz: -4
10 kHz: -2
16 kHz: +5

Here's the response I'm at so far with EQ:
Screenshot_20180209-101025 by ben.garner, on Flickr

All that being said, the system definitely sounds better than it did before all this. I'm most impressed with the subwoofer integration using Andy's advice. It's blended into the front MUCH better than I was ever able to achieve trying to adjust the subwoofer's time delay to match its phase with the front.

So, thoughts from anyone?


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## JohnKoz (Jan 11, 2018)

Good luck with tune! I haven't gotten there yet, or even close, with my build. So I can't be much help sorry but I will be keeping an eye on this post to learn what I can


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## gijoe (Mar 25, 2008)

Have you measured each side independently? You don't have the ability to EQ each side, but you may be able to use gain and the crossover's tweeter attenuation to balance the levels a bit better. Even passive, you can get a pretty respectable system. Don't be afraid to try the loudness feature. Loudness is a volume dependent EQ that will boost the lows and highs at low volumes, so even when you aren't listening loudly you still have a nice balanced sound. It's not a gimmick or a band aid, because of Fletcher Munson curves (https://en.wikipedia.org/wiki/Equal-loudness_contour) no tune will allow you to have a balanced sound at all volumes. It seems that you've done a pretty good job optimizing the tools you have available. I wish more people would learn to use what they have before throwing more equipment at a problem that could be solved with a little time and knowledge.


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## mzmtg (Dec 8, 2009)

gijoe said:


> Have you measured each side independently? You don't have the ability to EQ each side, but you may be able to use gain and the crossover's tweeter attenuation to balance the levels a bit better. Even passive, you can get a pretty respectable system.


I haven't yet, but that's a great suggestion.




gijoe said:


> Don't be afraid to try the loudness feature. Loudness is a volume dependent EQ that will boost the lows and highs at low volumes, so even when you aren't listening loudly you still have a nice balanced sound. It's not a gimmick or a band aid, because of Fletcher Munson curves (https://en.wikipedia.org/wiki/Equal-loudness_contour) no tune will allow you to have a balanced sound at all volumes.


I used to run the Loudness set at 1 (out of 3). I may go back to it. I'm still just riding around listening to it as is right now.


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## asianinvasion21 (Sep 24, 2012)

I would try to avoid boosting on the EQ and only cutting frequencies. You can cause distortion by boosting more than +2db.


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## Iamsecond (Jan 3, 2017)

I wasn’t trying to do the same with my kenwood ddx393 but the ta distances are set at increments that I couldn’t work with. Never could get that right. You have done a good job with the 13 band eq. 

As to the boosting statement. Boosting is not usually the preferred action but it isn’t a no no either.


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## SPLEclipse (Aug 17, 2012)

I would turn up the gain on the sub channel(s) and turn down the preamp gain for the low shelf filter so it's not maxed at +9. You might be able to play with the sub/mids crossover a bit to eliminate the need for the +4dB at 100hz as well (and raising the entire level of the sub with the amp might help with that as well depending on the roll-off of the sub).

The +4dB at 400hz is bothersome as well, but there's a very good chance you will hear it if you're causing distortion.


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## mzmtg (Dec 8, 2009)

asianinvasion21 said:


> I would try to avoid boosting on the EQ and only cutting frequencies. You can cause distortion by boosting more than +2db.





SPLEclipse said:


> I would turn up the gain on the sub channel(s) and turn down the preamp gain for the low shelf filter so it's not maxed at +9. You might be able to play with the sub/mids crossover a bit to eliminate the need for the +4dB at 100hz as well (and raising the entire level of the sub with the amp might help with that as well depending on the roll-off of the sub).
> 
> The +4dB at 400hz is bothersome as well, but there's a very good chance you will hear it if you're causing distortion.


Yeah, it looks like I may be chasing some cancellation with that boost at 400. I'll cut that back a little.

The volume scale on the head unit maxes out at 35. In my previous testing, I have confirmed that it does not clip with a 0db sine wave tone at 40Hz or 1000Hz played at max volume (35).

With the EQ set as described above, with a couple of big boosts, now the sound actually stops getting louder at a volume setting of 29. Turning it up past 29 doesn’t make the music any louder. So It looks like the head unit is cutting overall output when I’m asking it to put a bunch of power into a couple specific bands, possibly to avoid distortion. I don’t think I’m hearing any distortion in normal listening.

My previous setup was using the gains in the amp and the head unit crossover to get that ~12db boost in the sub bass that we all like. The result was, as everyone knows, it’s hard to get the subs and the mids to stay together when you turn it up.

I'm trying to emulate the bass control that the MS-8 does, as described here: http://www.diymobileaudio.com/forum.../8257-jbls-ms-8-processor-86.html#post1002963

And further explained here: https://www.audiofrog.com/community/tech-tips/time-alignment-part-4-getting-the-bass-right/



Andy Wehmeyer said:


> 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.


Looking at my EQ’d frequency response above, it looks like my sub-bass is actually more like 16-18db hotter than my mid-bass bands. So I can probably pull that bottom EQ band down from +9 to +7 at least. I’ll give that a shot later today and see how it goes. If it gives me back some more headroom in the head unit to play louder overall, I’ll be happy with that too.


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## chasingSQ (Sep 25, 2017)

never boost anything if you can help it , and why no tweeter measurements on the t/a screen ?


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## mzmtg (Dec 8, 2009)

audirsfaux said:


> never boost anything if you can help it


Clearly, I'm not following that old rule of thumb here.



audirsfaux said:


> , and why no tweeter measurements on the t/a screen ?


I'm running a passive 2-way setup up front, so my mids and tweeters are on the same channels. Since I can't T/A the tweeters separately, I didn't measure them.


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## chasingSQ (Sep 25, 2017)

mzmtg said:


> Clearly, I'm not following that old rule of thumb here.
> 
> 
> 
> I'm running a passive 2-way setup up front, so my mids and tweeters are on the same channels. Since I can't T/A the tweeters separately, I didn't measure them.


oh ok .


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## mzmtg (Dec 8, 2009)

I found a spreadsheet that converts the .at files from the Audio Tool app into a .txt file of 1/3 octave measurement data that can be imported in REW.

So here’s the comparison between my left & right channels with no EQ. I can see the right side is quite a bit down from 150 – 900 hz.
L&R no EQ Normalized by ben.garner, on Flickr

Here’s 3 separate measurements, Left, Right and Stereo.
L&R&Stereo no EQ Normalized by ben.garner, on Flickr

So I put together a couple of different EQ setups to try to bring the stereo response closer to either the Whitledge or JBL house curves. Obviously with a graphic EQ, I couldn;t just run the auto EQ function. So, I set my avaiable filters up and then adjusted them manually to try to get a decent curve fit. I tried to set the target level down so most of my filters are cuts with much smaller boosts. I also did not try to fill in the big hole at 400 Hz. I’ll try each one and see how well they work and how I like the sound.

Here’s the Whitledge curve EQ settings and the predicted response I came up with:

Whitledge EQ Filters by ben.garner, on Flickr

Whitledge EQ predicted by ben.garner, on Flickr

Here are the settings and the predicted response for the JBL curve.

JBL EQ Filters by ben.garner, on Flickr

JBL EQ predicted by ben.garner, on Flickr



Anyway, I’ll report back…


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## asianinvasion21 (Sep 24, 2012)

mzmtg said:


> Clearly, I'm not following that old rule of thumb here.
> 
> 
> 
> I'm running a passive 2-way setup up front, so my mids and tweeters are on the same channels. Since I can't T/A the tweeters separately, I didn't measure them.


You should honestly try running active if your head unit allows it. It will just take a small 2 channel amp to run the tweeters. It will give you a little more flexibility with crossovers and slopes. It will also drastically improve the imaging being able to time align each driver. My dads car has a basic 13 band eq and I was able to get it pretty flat by just cutting.

No Sub


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## mzmtg (Dec 8, 2009)

asianinvasion21 said:


> You should honestly try running active if your head unit allows it. It will just take a small 2 channel amp to run the tweeters. It will give you a little more flexibility with crossovers and slopes...


Well of course. I like seeing how good I can get things to work the way they are before I spend more money.

I do need a new head unit since my Kenwood has some kind of funky noise in the bluetooth audio section. Also, the display sucks. So I haven't decided which way to go with sources and processing really. It's not obvious to me if my money is better spent on a head unit with better crossover and processing capability or by going for an affordable DSP like a C-DSP or a used MS-8.

Amp-wise, my ultimate plan it to get a mono amp for the sub and then I'll have the channels for 2-way active in front, or bridge the 4-channel for 200 watts per side in a passive setup.


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## asianinvasion21 (Sep 24, 2012)

mzmtg said:


> Well of course. I like seeing how good I can get things to work the way they are before I spend more money.
> 
> I do need a new head unit since my Kenwood has some kind of funky noise in the bluetooth audio section. Also, the display sucks. So I haven't decided which way to go with sources and processing really. It's not obvious to me if my money is better spent on a head unit with better crossover and processing capability or by going for an affordable DSP like a C-DSP or a used MS-8.
> 
> Amp-wise, my ultimate plan it to get a mono amp for the sub and then I'll have the channels for 2-way active in front, or bridge the 4-channel for 200 watts per side in a passive setup.


The double din pioneer I bought for my dad was $180 new and it had pioneers network mode which allows 2-way active + sub. Its pretty amazing what you get nowadays for the price. I think any pioneer deck with network mode will give you a decent improvement on sound and staging.


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## mzmtg (Dec 8, 2009)

mzmtg said:


> Here’s the Whitledge curve EQ settings and the predicted response I came up with:
> 
> Whitledge EQ Filters by ben.garner, on Flickr
> 
> Whitledge EQ predicted by ben.garner, on Flickr


I put in these EQ settings and I definitely like the sound so far. I'll ride around this way for a couple days and see if it needs adjustment.


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## gijoe (Mar 25, 2008)

mzmtg said:


> Well of course. I like seeing how good I can get things to work the way they are before I spend more money.
> 
> I do need a new head unit since my Kenwood has some kind of funky noise in the bluetooth audio section. Also, the display sucks. So I haven't decided which way to go with sources and processing really. It's not obvious to me if my money is better spent on a head unit with better crossover and processing capability or by going for an affordable DSP like a C-DSP or a used MS-8.
> 
> Amp-wise, my ultimate plan it to get a mono amp for the sub and then I'll have the channels for 2-way active in front, or bridge the 4-channel for 200 watts per side in a passive setup.


People like you who learn to utilize the tools they have correctly before buying more tools will have a much better foundation than most other people. 

Since you need a new head unit anyway, I would look at the 80PRS. It's 3-way active (2way front plus sub). Many are going to recommend more robust DSP for 4-way setups, and that's fine, but I think you'll be able to do more with a 80PRS than most people can with the MS-8. It's going to come down to your needs and budget, but since you seem to be interested in taking full advantage of what you have, you can make an active 3-way shine.


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## Mic10is (Aug 20, 2007)

audirsfaux said:


> never boost anything if you can help it , and why no tweeter measurements on the t/a screen ?


boost is fine and often needed. but much depends on why the boost is needed. Is the null caused by a mode in the vehicle? is it cancellation? is it just a null at a single point in the measurement point?

Boosting is fine to get a desired curve, assuming the boost is not across more than an entire octave.
it will not cause distortion. This "myth" comes from when people would take a signal that was already at its peak and apply more boost to increase the output at those frequencies, most commonly in the bass and subbass regions


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## asianinvasion21 (Sep 24, 2012)

If your boosting just make sure to check the oscope after tuning the EQ. In my experience you may have to lower the gains a tad bit after boosting the EQ. At least if you are running your gain to the maximum before clipping.


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## mzmtg (Dec 8, 2009)

mzmtg said:


> I put in these EQ settings and I definitely like the sound so far. I'll ride around this way for a couple days and see if it needs adjustment.


Oooh, neato. I measured the frequency response after putting in the EQ settings I figured up manually in REW and this is what I get:

2018-02-14 Whit EQd Actual Response by ben.garner, on Flickr

VERY close to the target. So REW works! Who knew?


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## fcarpio (Apr 29, 2008)

asianinvasion21 said:


> You should honestly try running active if your head unit allows it.


I agree with this. You can keep the 4 channel for the mids and tweets and get a cheap(ish) class D mono for the sub. you seem to have the hang of tuning and you will benefit quite a bit from a proper time alignment alone, I think you know this by now. You could get the NVX JAD1200 for a couple of hundred bucks new and you will not be disappointed. These pop up every now and then used on ebay and can be had for much less than that.

EDIT: For $110 shipped this is something that may work for you:

http://www.diymobileaudio.com/forum/car-audio-classifieds/367290-audio-system-m-line-100-2-a.html

I know it is a two channel, but it can be bridged.


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## mzmtg (Dec 8, 2009)

fcarpio said:


> I agree with this. You can keep the 4 channel for the mids and tweets and get a cheap(ish) class D mono for the sub.


That's the ultimate plan. I intend to eventually get rid of the single cheap kicker sub in a prefab box for 2 12s in a properly designed box. So, theoretically, I'm looking for an amp that will give me ~300W rms into 4 Ohms (to use with my current sub) and then ~500 watts into 2 ohms (for the future 2-sub setup).

There are LOTS of decent, affordable amps out there that will do this for me.


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## mzmtg (Dec 8, 2009)

Well, hell, I just realized that REW can AutoEQ and optimize my graphic EQ. I didn;t see that I could ask it to just "optimize gains" on the filters where I specify the frequency and Q.

So, I'll see how it's numbers compare to mine...

Capture by ben.garner, on Flickr


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## SSSnake (Mar 8, 2007)

> I would try to avoid boosting on the EQ and only cutting frequencies. You can cause distortion by boosting more than +2db.


WTF is magical about +2db. Unless you have only +2db of headroom in your system at that frequency this is largely false. I agree completely that large boosts typically only make things worse because they are usually in an area where you have a null but setting some arbitrary limit of +2db is asinine. 

Mick already covered the comment about no boost.

I know everyone is trying to help but it is "better to remain silent and be thought a fool than to speak out and remove all doubt". I also realize that it is sometimes hard to convey your thoughts without pages of conditions but blanket statements like these mislead less experienced readers.

Having said all of this AS A GENERAL RULE I try to cut rather than boost and also don't try to fix every wiggle in the FR. Sometimes though you need a little boost but get you there


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## fcarpio (Apr 29, 2008)

SSSnake said:


> WTF is magical about +2db. Unless you have only +2db of headroom in your system at that frequency this is largely false. I agree completely that large boosts typically only make things worse because they are usually in an area where you have a null but setting some arbitrary limit of +2db is asinine.
> 
> Mick already covered the comment about no boost.
> 
> ...


LOL, I was going to jump all over the "no boost" comment but I got lazy and chose not to.


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## SSSnake (Mar 8, 2007)

fcarpio said:


> LOL, I was going to jump all over the "no boost" comment but I got lazy and chose not to.


Sorry all for the rant I just see things like this posted all of the time. It drives me nuts.

Sent from my SM-N950U using Tapatalk


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## mzmtg (Dec 8, 2009)

SSSnake said:


> Sorry all for the rant I just see things like this posted all of the time. It drives me nuts.
> 
> Sent from my SM-N950U using Tapatalk


Understanding how these things actually work and why one makes the adjustments one does can lead one to take such rules of thumb with a grain of salt.


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## Jeffdachefz (Sep 14, 2016)

For example If your max output is around X out of 62 and you want to boost, you'll have to go down the volume knob the more you boost just to compensate, plain and simple. Boosting affects the head unit pre-out for that particular frequency which will directly affect your amplifier output and can be easily over driven into clipping so you are not careful, you'll blow your stuff. Either boosted or pure EQ cuts styles of tuning will work and get you where you need, just be smart about it.


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## mojozoom (Feb 11, 2012)

REW can also tell you exactly where you can and can't boost. 

Before EQing a system it's a good idea to print out an Excess Group Delay plot for each driver so you know what regions to avoid.


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## SSSnake (Mar 8, 2007)

> For example If your max output is around X out of 62 and you want to boost, you'll have to go down the volume knob the more you boost just to compensate, plain and simple. Boosting affects the head unit pre-out for that particular frequency which will directly affect your amplifier output and can be easily over driven into clipping so you are not careful, you'll blow your stuff.


Another half truth. Try 6db of boost at 20khz. Do you clip appreciably sooner? Probably not. Now add 6db of boost at 20hz. Boosting 6db at 20hz will in all but contrived cases cause you to clip sooner. 20khz, meh, not really. Why? It will only take a few watts (ROUGH guesstimate) to get the 6db at 20khz. 6db at 20hz on the other had will take a lot more power/watts.

BTW - Why do you care if you have to turn down the volume knob some? Most songs aren't recorded at the same level. So between songs you have to adjust the volume knob (if you are trying to get max output). Songs with a ton of low bass typically have to be played back lower on most systems as well.

Guys we can do this all day long. The long and the short of it is that boosting is not something that should be avoided at all costs. It, like most other adjustments, need to be made with an understanding what is going on with the rest of the system.


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## Jeffdachefz (Sep 14, 2016)

SSSnake said:


> Another half truth. Try 6db of boost at 20khz. Do you clip appreciably sooner? Probably not. Now add 6db of boost at 20hz. Boosting 6db at 20hz will in all but contrived cases cause you to clip sooner. 20khz, meh, not really. Why? It will only take a few watts (ROUGH guesstimate) to get the 6db at 20khz. 6db at 20hz on the other had will take a lot more power/watts.
> 
> BTW - Why do you care if you have to turn down the volume knob some? Most songs aren't recorded at the same level. So between songs you have to adjust the volume knob (if you are trying to get max output). Songs with a ton of low bass typically have to be played back lower on most systems as well.
> 
> Guys we can do this all day long. The long and the short of it is that boosting is not something that should be avoided at all costs. It, like most other adjustments, need to be made with an understanding what is going on with the rest of the system.


as i said earlier, both methods work, just gotta be smart and know your system limits.


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## SSSnake (Mar 8, 2007)

> you'll have to go down the volume knob the more you boost just to compensate,


As I illustrated (or at least attempted to) in my previous post this is frequently NOT the case. For reference that was the half that was untrue.



> as i said earlier, both methods work, just gotta be smart and know your system limits.


Here ^ is were the truth enters the picture.

With that post I feel this horse has been beaten thoroughly to death. I'm out.


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## asianinvasion21 (Sep 24, 2012)

Jeffdachefz said:


> For example If your max output is around X out of 62 and you want to boost, you'll have to go down the volume knob the more you boost just to compensate, plain and simple. Boosting affects the head unit pre-out for that particular frequency which will directly affect your amplifier output and can be easily over driven into clipping so you are not careful, you'll blow your stuff. Either boosted or pure EQ cuts styles of tuning will work and get you where you need, just be smart about it.


Agreed, At least this is what I have experienced. When ever you boost EQ after setting the gains you will have less volume output on the head unit before clipping. It is always best to go back and check for clipping after boosting the EQ. Every head unit is obviously different when it comes to distortion on boosting. I just avoid boosting period if I can. If it adds any chance of clipping why not just avoid it. I'm sure some of the newer DSP's have a protection against this but some head units will definitely clip when boosting the EQ.


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## mzmtg (Dec 8, 2009)

asianinvasion21 said:


> I'm sure some of the newer DSP's have a protection against this but some head units will definitely clip when boosting the EQ.


See post #8 of this very thread: http://www.diymobileaudio.com/forum/5296754-post8.html


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## mzmtg (Dec 8, 2009)

+
YouTube Video









ERROR: If you can see this, then YouTube is down or you don't have Flash installed.







mojozoom said:


> REW can also tell you exactly where you can and can't boost.
> 
> Before EQing a system it's a good idea to print out an Excess Group Delay plot for each driver so you know what regions to avoid.


That's a good point. 

Right now, I'm not actually using REW to take my measurements. I;m using my phone then transferring the FR data into REW on my desktop.

Once I get REW onto my laptop and get a mic for that, then I can get more detailed with everything.

This is fun


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## mojozoom (Feb 11, 2012)

It sure is. It's a great hobby and gives us lots to ponder.


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## mzmtg (Dec 8, 2009)

In an effort to get some headroom back on the head unit's "preamp", I followed Andy's advice for those that don't have a low pass shelf filter in their DSP. I lowered the subwoofer cutoff frequency half an octave below the midrange HPF, so 60Hz and 80Hz, repsectivley and then turned the gain up on the subwoofer amplifier channels to get my +9db (or so) boost there.










This way I could get rid of the big boost in my EQ at 63Hz.

So with these EQ settings, I got this response:

2018-02-20 Whitledge Filters by ben.garner, on Flickr

2018-02-21 FR with subs up by ben.garner, on Flickr

I definitely have the headroom back in the head unit to play louder overall, but the subwoofer is not nearly as well integrated as it was before.

I'll keep messing with it (of course) to see if I can find a good compromise.


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## mzmtg (Dec 8, 2009)

mzmtg said:


> I definitely have the headroom back in the head unit to play louder overall, but the subwoofer is not nearly as well integrated as it was before.
> 
> I'll keep messing with it (of course) to see if I can find a good compromise.


I moved my sub crossover back up to 80Hz (matching the midrange high pass) and cut the gain on the amp back down some. 

This seems to have made a big improvement. Matching the crossover frequencies has kept the bass up front like it was. But, keeping a bit more gain in the sub amp than I had back in the beginning has let me increase the sub bass range without maxing out the boost in the EQ.

Here's the frequency responses of my subwoofer and front stage measured separately then overlaid. You can see that my actual acoustic crossover point is still in the right place (just about 80Hz).

2018-02-27 EQd Response Comparison by ben.garner, on Flickr

I then measured the frequency response with all speakers playing (red line). The green line is the measured response from a couple of weeks ago. I can see that I'm not getting any unwanted cancellation or interference at the crossover point and I've filled in the big dip I had at 63 Hz before (cursor). I can definitely hear this difference.

2018-02-27 EQd Actual Response Comparison by ben.garner, on Flickr


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## mzmtg (Dec 8, 2009)

I re-ran auto EQ with no boost, only cuts. These are the filter settings and the resulting measured frequency response. Still sounds pretty good, so I'll run this for a while and see if anything jumps out at me as needing more work.

2018-03-05 Whitledge Filters by ben.garner, on Flickr

2018-03-08 Whit EQd Actual Response by ben.garner, on Flickr


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## SubOptimal (May 6, 2017)

If you're using the Whitledge target curve, I think you'll find it's for single stereo channel. I.e. left side + sub.

If the last pic is you're overall response, then it looks too bass heavy and the highs roll off too quickly.


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## mzmtg (Dec 8, 2009)

SubOptimal said:


> If you're using the Whitledge target curve, I think you'll find it's for single stereo channel. I.e. left side + sub.
> 
> If the last pic is you're overall response, then it looks too bass heavy and the highs roll off too quickly.


Really? I did not know that.

Well, worth a shot to try something a little different then. I used the "Half of Whitledge" house curve from Jazzi's spreadsheet and came up with the following...

Here are the filter settings and predicted response from REW for that target curve:

2018-03-09 Half Whitledge Filters Sub Xover Minus 8 by ben.garner, on Flickr

2018-03-09 Half of whitledge predicted by ben.garner, on Flickr

I'll give that a shot and see how it sounds.

I don't know where that big peak at ~120Hz came from. I gotta get that thing under control.


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## SubOptimal (May 6, 2017)

You must get the left and right responses as close as possible before adjusting overall tonality.
The full Whitledge curve is a pretty good start point. But again, for one side (plus sub) at a time.


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## mzmtg (Dec 8, 2009)

SubOptimal said:


> You must get the left and right responses as close as possible before adjusting overall tonality.
> The full Whitledge curve is a pretty good start point. But again, for one side (plus sub) at a time.


I don't have separate left/right EQ.


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## mitchell0715 (Apr 11, 2015)

OP how can you get away with using a -10db sine wave for your gains? You'll surely be clipped on almost all music

or do you mean +10db?...


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## mzmtg (Dec 8, 2009)

mitchell0715 said:


> OP how can you get away with using a -10db sine wave for your gains? You'll surely be clipped on almost all music
> 
> or do you mean +10db?...


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## Weightless (May 5, 2005)

-10 is correct. 

Music isn't recorded at 0. If the music hits 0db, it'll clip, but usually it's in the lower frequencies where minor clipping isn't as noticable. 

Sent from my SM-N920P using Tapatalk


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## mzmtg (Dec 8, 2009)

mzmtg said:


> I don't know where that big peak at ~120Hz came from. I gotta get that thing under control.


Fixed it. I had my rear speakers on when I took those measurements this morning. I usually turn them off unless the kids are riding back there and want to jam. 

So, now here's where it stands, REW auto-eq filters and predicted response:

2018-03-09 Half Whitledge Filters Sub Xover Minus 6 by ben.garner, on Flickr

2018-03-09 Half of whitledge predicted-2 by ben.garner, on Flickr

My mid-to-sub transition has gone all to hell again, so I obviously need to figure out where that went off the rails too.

I've got a new subwoofer amp on the way (JBL GTX500 woo hoo). So I'll be rewiring the front speakers to use the MTX 4-channel in bridged mode which will give me a LOT more power to play with. Right now, I'm running about 60 watts per side in the front and about 200 to the sub. The new configuration will be (up to) 200 watts per side in the front and (up to) 500 to the sub. My speakers probably can't handle that much juice long term, so I'll make the necessary adjustments once it's all in and running.


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## mitchell0715 (Apr 11, 2015)

Weightless said:


> -10 is correct.
> 
> Music isn't recorded at 0. If the music hits 0db, it'll clip, but usually it's in the lower frequencies where minor clipping isn't as noticable.
> 
> Sent from my SM-N920P using Tapatalk


I'd like to learn more about this, but maybe that's for another thread..

I guess it may be okay on lower power amplifiers at say 50w per channel? but at 150w per channel I don't know if I want to risk blowing my speakers


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## mzmtg (Dec 8, 2009)

mitchell0715 said:


> I'd like to learn more about this, but maybe that's for another thread..
> 
> I guess it may be okay on lower power amplifiers at say 50w per channel? but at 150w per channel I don't know if I want to risk blowing my speakers <img src="http://www.diymobileaudio.com/forum/images/smilies/confused.gif" border="0" alt="" title="Confused" class="inlineimg" />


That 10db of overlap is 10db regardless of amplifier power.


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## mitchell0715 (Apr 11, 2015)

mzmtg said:


> That 10db of overlap is 10db regardless of amplifier power.


thats asking more 8x the amplifiers capabilities when a 0db portion of the track comes through


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## mzmtg (Dec 8, 2009)

mitchell0715 said:


> I'd like to learn more about this, but maybe that's for another thread..


Not to keep veering off-topic, but...

Here's a great article from RF about gain overlap: How to Properly Set Your Gains (Gain Tutorial)


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## mzmtg (Dec 8, 2009)

mzmtg said:


> Not to keep veering off-topic, but...
> 
> Here's a great article from RF about gain overlap: How to Properly Set Your Gains (Gain Tutorial)


To bring it back on-topic 

I am going to be installing a dedicated subwoofer amplifier this weekend. With that, I can run my 4-channel in bridged mode. This setup will give me more than double the power available to each channel. (Going from ~60 to the front & ~200 to the sub up to ~200 to each front channel and ~400 to the sub)

With this new setup, I will be setting the gains with a 5db overlap instead of 10 since I'll have plenty of power to get louder without getting into higher levels of clipping in the amp like I do now.

(I'm still debating whether to run the 4-channel in bridged mode or to use all 4 channels to biamp the front component speakers through the passive crossovers. Biamping would at least give me the ability to time align & set the level of each driver individually.)


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## mitchell0715 (Apr 11, 2015)

mzmtg said:


> Not to keep veering off-topic, but...
> 
> Here's a great article from RF about gain overlap: How to Properly Set Your Gains (Gain Tutorial)


I don't think it's off topic because it is relating to your tuning process and gain overlap is very important

32%thd seems awfully high, i mean with 10db of overlap doesn't that mean you're increasing the power dramatically? If I can set it with that much overlap, cool, but I really think it's going to heat up the voicecoils and eventually burn up my speakers considering they're on a ppi900.4


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## mzmtg (Dec 8, 2009)

mitchell0715 said:


> I don't think it's off topic because it is relating to your tuning process and gain overlap is very important
> 
> 32%thd seems awfully high, i mean with 10db of overlap doesn't that mean you're increasing the power dramatically? If I can set it with that much overlap, cool, but I really think it's going to heat up the voicecoils and eventually burn up my speakers considering they're on a ppi900.4


The only time you'd actually get to 32% thd is at the source unit's maximum volume setting AND playing a zero dB signal. 

When does that actually happen with music and not just test tones? Not very often. 

Even then, these millisecond scale passages of clipped signal won't damage the voice coils.


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## mzmtg (Dec 8, 2009)

mzmtg said:


> (I'm still debating whether to run the 4-channel in bridged mode or to use all 4 channels to biamp the front component speakers through the passive crossovers. Biamping would at least give me the ability to time align & set the level of each driver individually.)


And there she sits, new subwoofer amp mounted under the passenger seat:



I am using the 4-channel MTX amp to biamp the front components for now. So the front channels power the tweeters through the JBL passive crossovers. The rear amp channels power the midrange speakers with no low pass crossover. The JBL passive put a full range signal to the midranges already, so they are meant to run this way. (See here and here)

So now the whole tuning rigmarole begins anew...


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## mzmtg (Dec 8, 2009)

mzmtg said:


> I am using the 4-channel MTX amp to biamp the front components for now. So the front channels power the tweeters through the JBL passive crossovers. The rear amp channels power the midrange speakers with no low pass crossover. The JBL passive put a full range signal to the midranges already, so they are meant to run this way. (See here and here)
> 
> So now the whole tuning rigmarole begins anew...


This seems to be working out really well so far. I have the tweeters running off the rear channels of the head unit and the mids off the front channels. This lets me apply a little bit of a low pass crossover to the mids. The kenwoods have a setting for a tweeter "crossover" adjustment. This is a low pass filter that attenuates all high frequencies on the front channels with an adjustable frequency and gain.

So, I set the frequency to 2.5k and the gain all the way down at -8db. This is how it affects the output of my midrange speakers (response is measured with no other EQ applied):



With the passive crossovers installed for the tweeters, this is what my front stage looks like (again with no EQ applied, just crossovers):



Not bad at all....


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## mzmtg (Dec 8, 2009)

Little update...

I hadn't been adjusting the delay on my single subwoofer so far. I had been trying everything this way due to seeing Andy W's advice everywhere he posts that it isn't really necessary. His explanations are obviously sound and make sense on their face.

But, I had had good results delaying the sub in my previous car. So I started delaying my subwoofer while watching the SPL at the crossover frequency, 80Hz. I ended up with a delay of 3.37ms, which is a phase difference of 97 degrees.

The bass is definitely more tied to the front of the car now and the whole image is much more clearly focused up front. Everything has tightened up.


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## mzmtg (Dec 8, 2009)

No more measuring and REW for me.

I picked up an MS-8. Right now it's just sitting in my passenger footwell while I get used to using it. So far, after a few days use, I like it A LOT.

This is the (obviously) temporary setup, also including the JL Audio bluetooth receiver as the source.


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## mzmtg (Dec 8, 2009)

I've been working with the MS8 over the last couple of weeks to get familiar with how the different settings can affect the final sound. As I said above, I am LOVING this thing. I can tweak the big picture settings that make the most difference (crossovers & gains, essentially), let the auto EQ do its thing, then fine tune it from there to my personal preference. 

My biggest impression of this thing over what I was doing before is _detail_. I’m hearing texture and layers to the music that I’ve never heard in songs that I’ve been listening to for 20 years. It’s really a lot of fun.

Today I took the first measurements of what it's actually doing. As before , using my phone and the Dayton IMM6 mic.

Right now, the sub/mid crossover is set to 85 Hz (24 db/oct) and the mid/tweeter is set to 2950 Hz (24 db/oct). Here's the 1/3 octave response with the processing switched off (RED line) compared to processing on, GREEN line):



Right off the bat, I see it has fixed the big dips I had at 63Hz and 400Hz before. I also see that my subwoofer REALLY needs to be in a bigger box. Looks like I can also turn up the gain on the sub amp just a bit and re-run the calibration. The MS8 is adding a LOT of bass. I also see that I could try adding a few DB via the 31-band EQ to the entire top octave. Man, that’s a HARD roll off on the very top end.


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## mzmtg (Dec 8, 2009)

I spent a little time with the 31 band EQ built in to the MS8. It's really very cool that I can make adjustments and watch the effects real time on my RTA. It's great that I just "draw" the filters I want and the MS8 figures out how to make that happen without me having to EQ each driver or mess with crossovers or any of that.

Here's the raw system response with no processing:


Here's the response with the automatic processing:


Here are the EQ adjustments I made and the resulting response:





Easy peasy.


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## Dillinger (Aug 27, 2021)

mzmtg said:


> I found a spreadsheet that converts the .at files from the Audio Tool app into a .txt file of 1/3 octave measurement data that can be imported in REW.
> 
> So here’s the comparison between my left & right channels with no EQ. I can see the right side is quite a bit down from 150 – 900 hz.
> L&R no EQ Normalized by ben.garner, on Flickr
> ...


What is this spreadsheet you speak of? 😄


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## mzmtg (Dec 8, 2009)

Dillinger said:


> What is this spreadsheet you speak of? 😄



Right here: Bofinit Corporation - AudioTool - Online Manual


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## Dillinger (Aug 27, 2021)

mzmtg said:


> Right here: Bofinit Corporation - AudioTool - Online Manual


Sweet thank you so much.


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## gmack7277 (10 mo ago)

YOu still running the RAM 3C's? How do they compare to the JL C2 3.5's you had?


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## mzmtg (Dec 8, 2009)

gmack7277 said:


> YOu still running the RAM 3C's? How do they compare to the JL C2 3.5's you had?


I'm still getting them dialed in. I'm using the outboard passive crossovers with them as well. 

Compared to the JL's there's a lot more detail, especially in the high end, which is exactly what I wanted. Their sound has mellowed quite a bit in the 2 weeks I've been running them, but the 6 - 16k range still needs attention, it gets harsh on some songs when I play it loud...


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