# Ms-8 Center Channel Speaker



## luttman1973 (Mar 31, 2009)

Whats the ideal speaker or speakers to run for a center channel.For people that are running a center channel what are you guys using.Thanks ed


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## eng92 (Oct 28, 2008)

If you read the MS-8 thread, it is suggested that the centre channel low frequency driver be the same size as what you are using for the front L & R.

I cannot fit an 8 in the centre, so I am going with a 6.5 and a 1" dome on top of the dash fitted with an acoustic lens. Here is the 6.5 partially installed.


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## CraigE (Jun 10, 2008)

Any pics, or more info about the acoustic lens ?


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## eng92 (Oct 28, 2008)

CraigE said:


> Any pics, or more info about the acoustic lens ?


I am just doing my own knock-off of the B&O unit. (it will not be a pop-up style though)

Acoustic lens technology < Bang and Olufsen Advanced Sound System < A8 < A8 < Models < Audi UK

http://www.sausalitoaudio.com/pdf/SAU_ALMA_WPaper_R1.pdf


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## thehatedguy (May 4, 2007)

As big as you can get. And on axis as much as possible.


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## 14642 (May 19, 2008)

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


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## mattyjman (Aug 6, 2009)

Andy Wehmeyer said:


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


wait, really? are you being sarcastic?


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## t3sn4f2 (Jan 3, 2007)

mattyjman said:


> wait, really? are you being sarcastic?


No, he's serious. Show him your thread and see what he thinks about what I mentioned about the windshield angle.


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## thehatedguy (May 4, 2007)

Hmm, redoing my center channel now...on axis or up at the glass?

Maybe some of both?


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## MarkZ (Dec 5, 2005)

I would think 'both' is what you should try to avoid...


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## thehatedguy (May 4, 2007)

I had the last one sort of angled up at the dome light...which was what I was thinking as sort of "both"


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## MarkZ (Dec 5, 2005)

Haha if the speaker was large enough and the polar response was narrow, maybe instead of 'both' it was really 'neither'.


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## 14642 (May 19, 2008)

^^^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.[/


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## mitchyz250f (May 14, 2005)

Wow, thanks for clearing that up Andy. But one question, you wrote that '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'.

Did you mean windshield and not dash? 

Are you saying with the ms8, the doors are better location than kicks or just the simpliest? In your description there is no tweeter, correct, just a three inch mid pointing at the windshield. How high should it be able to play. My current mids only go to 10K, is that good enough?


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## 14642 (May 19, 2008)

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.


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## MarkZ (Dec 5, 2005)

Care to reveal how center is computed with the MS8, or is this proprietary?


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## t3sn4f2 (Jan 3, 2007)

MarkZ said:


> Care to reveal how center is computed with the MS8, or is this proprietary?


http://www.diymobileaudio.com/forum/1002963-post2151.html


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## lycan (Dec 20, 2009)

MarkZ said:


> Care to reveal how center is computed with the MS8, or is this proprietary?


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*.


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## CraigE (Jun 10, 2008)

I'm onboard with the 3" mids.

I recently installed 3" (Faital) mids in the stock upper door locations, and shoe horned a 4" (JBL P462) coax in the stock center location.

This is the best combination so far, in my car. 3-way fronts, ctr, sides, sub.


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## AAAAAAA (Oct 5, 2007)

I just added a center, I used a factory opening in the car, it is like hatedguy's: pointing more or less at the dome light. 

Managed to cram a 5 1\4 and xover it at 80hz... it's to low for the driver because I can see it bounce around way to much HOWEVER

A center channel adds so much, I love it, I am extremely glad that I am making the move.

Interestingly, there is still an advantage to setting "driver" as oppose to "front" for both passengers. Optimal results are still just for one person in my limited experience so far.

Can't wait to throw in the rears.


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## MarkZ (Dec 5, 2005)

lycan said:


> 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*
> ...


And this is what I was curious about. I can think of a few ways to try to do this with the whole signal, but how it's done in real time is very mysterious to me...


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## 14642 (May 19, 2008)

Try this. Logic 7 is David's baby:

http://www.davidgriesinger.com/sur.pdf


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## thehatedguy (May 4, 2007)

Yeah, but my center is an oval- 5x7 coax .

I know...still doesn't matter much.


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## thehatedguy (May 4, 2007)

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.


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## mitchyz250f (May 14, 2005)

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?


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## 14642 (May 19, 2008)

mitchyz250f said:


> 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?


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


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## wadejg (Apr 20, 2007)

Andy Wehmeyer said:


> 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.


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


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## mattyjman (Aug 6, 2009)

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


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## 14642 (May 19, 2008)

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


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## Dangerranger (Apr 12, 2006)

thehatedguy said:


> Yeah, but my center is an oval- 5x7 coax .
> 
> I know...still doesn't matter much.


IMO this really poses an interesting argument as oval speakers will beam in a different way than round speakers, a rather peculiar radiation pattern realistically, not dissimilar to a ribbon tweeter or electrostatic panel 

For example, say you use a door location with the smaller side of the speaker aimed at the listener...say that 5x7...do you choose a crossover point more relative to how a 7" driver would beam, or more like a 5" driver and just deal with the poorer dispersion of the longer axis of the speaker?


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## kkant (Feb 3, 2008)

wadejg said:


> I'm trying to figure out how, assuming 1 channel used for a sub, you would use the other 7 channels left.


If you are running out of output channels on the MS8, then try assigning channels in this way: Use a separate MS8 channel only for speakers that are physically separated. Use outboard active or passive xovers for the rest. So for your center woofer and teeter, which are presumably in the same place, use a single MS8 channel. For your front L/R speakers, if your woofers are low in the doors and the tweeters are far away on the top of the doors or the dash, use separate MS8 outputs for the woofers and tweeters.


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## kkant (Feb 3, 2008)

Dangerranger said:


> IMO this really poses an interesting argument as oval speakers will beam in a different way than round speakers....say a typical 6x9 speaker or the 5x7 coax you mention
> 
> For example, say you use a door location with the smaller side of the speaker aimed at the listener...say that 5x7...do you choose a crossover point more relative to how a 7" driver would beam, or more like a 5" driver and just deal with the poorer dispersion of the longer axis of the speaker?


I think in general, as you approach beaming territory you start leaving the pistonic range. I'd err on the safe side and cut it off according to the beaming characteristics of the larger dimension of the oval.


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## Dangerranger (Apr 12, 2006)

kkant said:


> I think in general, as you approach beaming territory you start leaving the pistonic range. I'd err on the safe side and cut it off according to the beaming characteristics of the larger dimension of the oval.


I believe so too in a 2 way.

Just the concept is intriguing  Realistically even in a home, only about 30% of what you hear is direct sound. Now think about the automobile.....wow. I'd probably cut that in half. but realistically on the similar note: a line array could be a very good thing in a vehicle, angling the speakers toward you for direct radiation, but positioning them in such a way that it cuts back a lot of the reflections from the dash, windshield, etc. Whereas in a home I'd argue in favor of a 2.5 way arrangement, an MTM in a vehicle (or more extreme circumstances) makes a lot of sense. Now of course, an oval speaker is an entirely different story.

But say you compared two speakers: a 6x9 versus an 8" round speaker. Very similar, almost exactly the same in surface area. If the smaller side of the 6x9 was directed toward the listener, can you "get away" with a higher crossover point, would be the interesting question to ask.


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## thehatedguy (May 4, 2007)

IRL, there is a difference in frequencies at which each side will beam, but I don't know how much of it is really that important. A 7" cone will beam ishy of 2k hertz while a 5" cone will beam around 2750. I can get my tweeters to play that low...I just don't like to do so. And there really isn't a nice way to do a wideband driver AND a large midbass. I could probably have went with a smaller midbass and a wideband or a dome midrange, but having a large center channel midbass was more important to me. Which in the space that I have, a 5x7 maximizes cone area and foot print while allowing a stock looking dash.


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## mitchyz250f (May 14, 2005)

thehatedguy - Why can't you do what Mark did to get the better dispersion, with the star-shaped thing.


'if the tweeter and mid on the center are close, there is no reason why you would need two channels for that... so a passive'. 

So if the mid is pointing straight up, where do the tweeter go? Facing up also, or at the front of the pod down the center of the car, or at the back of the pod?


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## MarkZ (Dec 5, 2005)

Sounds like a great application for a coaxial.


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## nar93da (Dec 11, 2008)

Andy,

What are your thoughts on using a full range driver for a center? I can't fit a decent size speaker for a center. The biggest I could fit is a 3.5", maybe 2 depending on the frame size. I'm using the storage pocket above the radio in my G35. Thank you


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## AAAAAAA (Oct 5, 2007)

^It's been said by Andy before, center should be able to go as low as your side speakers and that a tweeter is needed.


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## quality_sound (Dec 25, 2005)

AAAAAAA said:


> ^It's been said by Andy before, center should be able to go as low as your side speakers and that a tweeter is needed.


He also said if it can't it's not a big deal.


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## wiseman454 (Nov 30, 2009)

Sorry for being a dolt but 3-way as in sub, mid, tweet or 
Sub, midBass, Mid and tweet?
Give me a free search pass please. I just pulled waaay to many 14 hour days in a row.( Not including honey-do time)
Can I run a fully active 4-way AND a center with the Ms-8?
aka Sub, Midbass, mid, tweet and center.. Center would be mid-tweet passive.


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## kkant (Feb 3, 2008)

wiseman454 said:


> Sorry for being a dolt but 3-way as in sub, mid, tweet or
> Sub, midBass, Mid and tweet?


The latter.



wiseman454 said:


> Can I run a fully active 4-way AND a center with the Ms-8?
> aka Sub, Midbass, mid, tweet and center.. Center would be mid-tweet passive.


Sure. You may have to use outboard passives or actives if there are not enough MS8 outputs.


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## quality_sound (Dec 25, 2005)

tw, mid, mb


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## kkant (Feb 3, 2008)

thehatedguy said:


> IRL, there is a difference in frequencies at which each side will beam, but I don't know how much of it is really that important. A 7" cone will beam ishy of 2k hertz while a 5" cone will beam around 2750. I can get my tweeters to play that low...I just don't like to do so. And there really isn't a nice way to do a wideband driver AND a large midbass. I could probably have went with a smaller midbass and a wideband or a dome midrange, but having a large center channel midbass was more important to me. Which in the space that I have, a 5x7 maximizes cone area and foot print while allowing a stock looking dash.


Those 5x7's often come with weak low-excursion motors, resulting in nonlinearity -- which the MS8 can't compensate for. Not to mention, I'm not sure what the unorthodox cone shape does to the response and breakup modes -- more work for the MS8 to do. You may be better served with a high quality 5" round driver with higher and more linear excursion. In fact your linear SPL and resulting low freq capability may be even better with the 5", because of the higher excursion motor.


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## BigRed (Aug 12, 2007)

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


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## 14642 (May 19, 2008)

kkant said:


> Those 5x7's often come with weak low-excursion motors, resulting in nonlinearity -- which the MS8 can't compensate for. Not to mention, I'm not sure what the unorthodox cone shape does to the response and breakup modes -- more work for the MS8 to do. You may be better served with a high quality 5" round driver with higher and more linear excursion. In fact your linear SPL and resulting low freq capability may be even better with the 5", because of the higher excursion motor.


The non-round shape of oval speakers tends to make cone distortion irregular, which spreads the chaos around and reduces the magnitude of peaks and dips. That's a good thing.


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## fuji6 (Feb 4, 2008)

Andy Wehmeyer said:


> No, MS-8 will work with either. Doors will give you a wider stage, so long as you have a center.


So with 3" mids in the doors. Ideal tweeter placement would be where? 
Also given you are also running sides/rears, would you place your passive xover depending on tweeter position? for instance Tweeters near the mids would probably mean using the passive on mids/tweeters.... with the tweeters farther (maybe a pillars) would mean using the passive on the mid/mid-bass....?


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## MarkZ (Dec 5, 2005)

I'd use the passive crossover between the mid and tweeter, regardless of position. Mostly because of the power response, clipping issues with the tweeter, insertion loss (for lack of a better term), size of the passive crossover, etc. Also, there are several midranges that exhibit a natural high frequency rolloff, which would also cut down on the parts count.

Not sure what the MS8 prefers, because I'm not completely clear on how it autotunes, but it's hard for me to imagine it relying so heavily on midrange/tweeter placement that you would want to put the passives on your woofers.

The real question worth asking is why anyone would put 3" mids in the lower doors?


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## AAAAAAA (Oct 5, 2007)

^From what I have read from AndyW's posts here and there

*Ideally* run the side tweets active in the a-pillars and maintaint your mid lower in the doors.

For the 3 inch, it all goes back to beaming, the 3 inch in the door will pretty much have the same FR through out it's range because it won't beam(When run with a tweet of course). Andy has said a few times that keeping the midrange in doors makes the stage wider.It's all about avoiding beaming: that is pretty much the opposite of what lycan and P bateman have been looking into the past few months.


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## MarkZ (Dec 5, 2005)

Why a 3" in the lower door and not a larger more sensitive wider bandwidth driver if it's going to be mated with a tweeter? 3 inch speakers suck. [with the exception of a few applications...]


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## 14642 (May 19, 2008)

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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## hallsc (Oct 26, 2008)

Sorry Andy, but are we supposed to be trying to match the center speaker to the midRANGES in the doors, or the midBASSES in the doors? If we had the option between a 6.5" coax and a 3" or 4" mid next to a tweeter (passively crossed), which would you recommend? 
Also, say we can't get anything bigger than 3" or 4" - is the MS-8 going to feed the missing midbass to the doors? IOW, if we have a 3-way in the door, and the 6.5" midbass is high-passed at like 80 Hz, and the 3" center is HP'd at like 500 Hz (not actual numbers here, just examples), will the MS-8 distribute 500 Hz and below to the left and right as if there was no center channel and play all the midbass there, or do we lose that, and only get left and right separated? Hopefully I am getting my point/question across correctly...


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## thehatedguy (May 4, 2007)

I would agree with that part about the motors...but the xS57 that I am using has a very nice strong neo motor with decent excursion. It's the same motor that is used on the xS65s.

The oval cone as Andy stated has less modal issues than a round cone. Which as he states is a good thing.

And with the fronts highpassed at 80 or 90 hertz, cone area would be more important than excursion in terms of output. You just aren't going to play these speakers low enough to make use of a ton of excursion.

The only limiting factor in my SPL is the power from the MS-8's internal amps.



kkant said:


> Those 5x7's often come with weak low-excursion motors, resulting in nonlinearity -- which the MS8 can't compensate for. Not to mention, I'm not sure what the unorthodox cone shape does to the response and breakup modes -- more work for the MS8 to do. You may be better served with a high quality 5" round driver with higher and more linear excursion. In fact your linear SPL and resulting low freq capability may be even better with the 5", because of the higher excursion motor.


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## thehatedguy (May 4, 2007)

Yeap. Whatever the center doesn't play gets sent to the fronts.



hallsc said:


> Sorry Andy, but are supposed to be trying to match the center speaker to the midRANGES in the doors, or the midBASSES in the doors? If we had the option between a 6.5 coax and a 3" or 4" mid next to a tweeter (passively crossed), which would you recommend? Also, say we can't get anything bigger than 3" or 4" - is the MS-8 going to feed the missing midbass to the doors? IOW, if we have a 3-way in the door, and the midbass is high-passed at like 80 Hz, and the center is HP'd at like 500 Hz (not actual numbers here, just examples), will the MS-8 distribute 500 Hz and below to the left and right as if there was no center channel, or do we lose that, and only get left and right separated? Hopefully I am getting my point/question across correctly...


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## thehatedguy (May 4, 2007)

I 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.



BigRed said:


> 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


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## hallsc (Oct 26, 2008)

thehatedguy said:


> I 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.


How did THAT turn out? What are you rockin in the center compared to the fronts?


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## DS-21 (Apr 16, 2005)

Andy Wehmeyer said:


> Yeah, what gives with all of the "wideband" stuff? A three inch doesn't make bass and it doesn't make high-frequencies..


A desire to compromise ultimate HF extension and to some degree ultimate SPL (though I think at the Georgia G2G there were some people who were surprised at how loud even a 2" widebander crossed at ~700Hz can get) for no directivity mismatch in the midrange, and getting the highpass high enough to avoid the soundstage separation that occurs with door mounted midbasses and high tweeters.

("You Are the Everything" on R.E.M.'s "Green" is a track that really suffers from this problem.)

Yes, a well-designed (concentric/coincident) coax may be better. But they're more expensive, and often far deeper than widebanders.


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## kkant (Feb 3, 2008)

thehatedguy said:


> The oval cone as Andy stated has less modal issues than a round cone. Which as he states is a good thing.


What would be the downside of oval cones, I wonder? Why isn't everyone using them in that case?



thehatedguy said:


> And with the fronts highpassed at 80 or 90 hertz, cone area would be more important than excursion in terms of output.


In terms of output, both are equivalent and equally important. area*excursion=volume.



thehatedguy said:


> You just aren't going to play these speakers low enough to make use of a ton of excursion.


I must listen a lot louder than you guys. I can almost guarantee that I'd blow out the 5x7's at 80 Hz, listening to music. I've done it several times before.


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## Dangerranger (Apr 12, 2006)

kkant said:


> What would be the downside of oval cones, I wonder? Why isn't everyone using them in that case?


well realistically the strength of the cone *can* be stronger in a round speaker. But can is the key word. Realistically anybody using a poly or similarly damped cone in a round midbass doesn't have a whole lot of room to talk about cone breakup of an oval speaker because their drivers are just as guilty. If anything you can get away with a stiffer cone material with oval cones just due to not having a characteristic breakup node as does a round speaker.

Manufacturers can either choose to damp the breakup or push it past the intended frequency range. Damping it would be the choice of the majority of manufacturers. The other end of the spectrum includes drivers like the SEAS Excel magnesiums. Another very good example would be the L18 7" midbass driver in the Prestige lineup, which uses a cone profile that pushes the primary breakup node to ~7khz. It's one of my favorite 7" drivers for that reason, what it lacks in a bit of refinement compared to the Excels, it makes up for by being very effective in a 2 way because you can cross it over in the 2-2.5khz region and not worry about 3rd order distortion exciting the breakup node as much.



kkant said:


> In terms of output, both are equivalent and equally important. area*excursion=volume.


This is true, but cone area is much preferred over excursion as the method to achieve this IMO. You don't have to worry about linearity of the motor as much, inductance variation as much, the driver with more cone area will be more efficient apples to apples, and on top of that relying on excursion to get deep bass you have to worry about distortion levels as well as power compression



kkant said:


> I must listen a lot louder than you guys. I can almost guarantee that I'd blow out the 5x7's at 80 Hz, listening to music. I've done it several times before.


True, but as you said earlier, there's a serious lack of quality 5x7 speakers.

Realistically, if you were to compare some old school JBL T595 speakers, you'd be hardpressed to find many drivers that will outperform their midbass in a car. The cone shape isn't inherently evil, just the effort applied into the driver in question and it's implementation.


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## Dangerranger (Apr 12, 2006)

DS-21 said:


> A desire to compromise ultimate HF extension and to some degree ultimate SPL (though I think at the Georgia G2G there were some people who were surprised at how loud even a 2" widebander crossed at ~700Hz can get) for no directivity mismatch in the midrange, and getting the highpass high enough to avoid the soundstage separation that occurs with door mounted midbasses and high tweeters.


Damn shame i missed it. I live in Georgia but had prior commitments. Been debating on trying whispers in my truck as the stock dash spots actually had 2" drivers in the factory "premium" system.



DS-21 said:


> Yes, a well-designed (concentric/coincident) coax may be better. But they're more expensive, and often far deeper than widebanders.


Maybe we could convince KEF to beef up those little 3.5" concentric drivers they use in the HT satellite systems and give it a more IB friendly design in 4 ohms?


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## DS-21 (Apr 16, 2005)

Actually, the baby Uni-Q's _are_ quite beefy. I bought a pair of the HTS1001 eggs with intention to use them in a car project. Three-inch Uni-Q's. The frames look like the flagship TC Sounds frames in miniature. 

And the drivers are also marked 4Ω, though honestly who gives a damn if 4Ω or 8Ω as long as they get loud enough without lots of dynamic compression?

And as for "IB friendly," one really shouldn't run such a small driver low enough that the enclosure matters anyway.


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## Dangerranger (Apr 12, 2006)

DS-21 said:


> Actually, the baby Uni-Q's _are_ quite beefy. I bought a pair of the HTS1001 eggs with intention to use them in a car project. Three-inch Uni-Q's. The frames look like the flagship TC Sounds frames in miniature.
> 
> And the drivers are also marked 4Ω, though honestly who gives a damn if 4Ω or 8Ω as long as they get loud enough without lots of dynamic compression?


Good to know, maybe I'll try to dig up an Ebay deal  Have heard them before but obviously never gutted them. If you still have them laying around, could you do me a favor and give an estimate on what the mounting cutout as well as mounting depth would have to be to use some of those little guys?



DS-21 said:


> And as for "IB friendly," one really shouldn't run such a small driver low enough that the enclosure matters anyway.


True. but from what I remember those drivers did have fairly impressive bass response for the size everything considered


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## thehatedguy (May 4, 2007)

Damn it. You guys are going to make me spend more money.

Any widebanders that one should be looking at?

The center crossed really low was fun, but it would be for a "judging thing" only type of deal.

Why aren't more people doing oval speakers? It is probably easier to engineer round cones. There is a stigma around oval cones not sounding good. But that is from years of bad oval speakers...cause most of them do suck, but their round counterparts probably do too. JL was one of the first companies to really do a good oval speaker years back in the XR line- not counting the 6x9 KEFs. You have to think that at one point nearly every Toyota, Ford, and Nissan had 5x7/6x8s in the front...and that is a great up sale to people wanting good sound without installation issues.

Yeah, you can get the same volumetric displacement from a smaller speaker with higher excursion. But for the reason stated above, I would rather use surface area to get my output. Plus I like the sound of large midranges.


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## Dangerranger (Apr 12, 2006)

thehatedguy said:


> You have to think that at one point nearly every Toyota, Ford, and Nissan had 5x7/6x8s in the front...and that is a great up sale to people wanting good sound without installation issues.


Most of the newer Toyotas and a lot of Nissans are using 6x9s up front now. My truck does. I'd say there's a pretty good demand solid 6x9" midbass drivers these days honestly.


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## thehatedguy (May 4, 2007)

Not to mention Dodge has been using 6x9s for a while too.

I think some forward thinking companies (shamless plug for ID and JL) have seen this and have gotten into the oval speaker market. You can do a few things- make a plate and use a smaller speaker, but if you are used to the output for a 6x9 that has the cone area of an 8 then chances are a 6 isn't going to cut it. You can cut the hole larger and use a larger round speaker, which if you lease the car this isn't much of an option. Or you can drop in a good oval speaker that maximizes the cone area of the cutout.


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## Dangerranger (Apr 12, 2006)

I'm definitely rethinking the idea of using the 6x9 hole as the 6.5s currently are a bit lacking in the midbass dept. looking at older T595s and similar, wish I could find some of the old KEF 690Qs


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## kkant (Feb 3, 2008)

Dangerranger said:


> well realistically the strength of the cone *can* be stronger in a round speaker. But can is the key word. Realistically anybody using a poly or similarly damped cone in a round midbass doesn't have a whole lot of room to talk about cone breakup of an oval speaker because their drivers are just as guilty. If anything you can get away with a stiffer cone material with oval cones just due to not having a characteristic breakup node as does a round speaker.


Seems to me that there must be more to it than that--else we'd see Scans and Seas ovals. It could just be an audio-snob thing against ovals, but I would think the DIY community which is the market for these things would try to be more technically objective than that.



Dangerranger said:


> This is true, but cone area is much preferred over excursion as the method to achieve this IMO. You don't have to worry about linearity of the motor as much, inductance variation as much, the driver with more cone area will be more efficient apples to apples, and on top of that relying on excursion to get deep bass you have to worry about distortion levels as well as power compression


Good points for a home speaker, but I disagree for a car--because of the dispersion issue. Bigger cones mean less consistent dispersion at the xover, and we are primarily hearing the power response in a car. And also because in a car we are generally limited in cone area because of space issues--so we need huge excursion anyway to make use of the limited space. The downside is, of course, that the best motors tend to cost a lot....but it's just money, right? 

I like to keep the low pass cutoff on my woofers on the low side with respect to cone area. To me, the harshest and most egregious problems from speakers come from the breakup modes in the passband and even outside the passband excited by nonlinearity. The smaller the cone, the higher I can cut off without any danger of running into those issues.


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## thehatedguy (May 4, 2007)

There was a set of KEF 6x9s on evilBay a couple of weeks back.

Has anyone used the little Aurasound Cougars?

Man I tell you, I am loving these little Vifa DQ25 tweeters...just don't like crossing tweeters over low and putting them up high. They don't play low enough to get a coherent stage like DS-21 mentioned. But damn, these little guys for a $13 tweeter sound so much better than what the price says they should.


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## thehatedguy (May 4, 2007)

You ever try to countersink an oval speaker? They don't make Perfect Oval jigs....

Plus in the home, why bother with an oval speaker? You don't have the space and install constraints you have in the car.

I wouldn't give the home DIY market that much credit (with a few exceptions). We know compression drivers have orders of magnitudes less distortion than cone drivers, but they still don't use them very much.



kkant said:


> Seems to me that there must be more to it than that--else we'd see Scans and Seas ovals. It could just be an audio-snob thing against ovals, but I would think the DIY community which is the market for these things would try to be more technically objective than that.
> .


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## kkant (Feb 3, 2008)

thehatedguy said:


> You ever try to countersink an oval speaker? They don't make Perfect Oval jigs....


Ha! Good point, of course you are correct.



thehatedguy said:


> Plus in the home, why bother with an oval speaker? You don't have the space and install constraints you have in the car.


If the asymmetry of the oval really did reduce breakup by a significant amount, I'd bet many home DIY'ers would use them. I think your first point is the real reason.

I just wish there was a 6x9 with a revelator motor attached to it. Then I'd be sold. What large excursion 6x9's are there? Any nonlinearity tests done on them ala zaph?



thehatedguy said:


> We know compression drivers have orders of magnitudes less distortion than cone drivers, but they still don't use them very much.


Most sources I've seen indicate the opposite (and give reasons for the higher distortion of CD's). Do you have links to tests showing otherwise? Not necessarily disagreeing, just looking for more info.


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## thehatedguy (May 4, 2007)

Geddes is the man when it comes to compression drivers. The problem is bad designed horns.

Sadly I don't know of anyone in the home world who has tested an modern oval speakers. And I do not really know of any large excursion 6x9s....nothing with over 4mm one way.


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## kkant (Feb 3, 2008)

Dangerranger said:


> Realistically, if you were to compare some old school JBL T595 speakers, you'd be hardpressed to find many drivers that will outperform their midbass in a car.


From the specs, it looks like the Scan 18W's will kill the Kef and JBL 6x9's in midbass, despite the smaller cone area. I'd love to try a good 6x9, it would fit perfect in my ride, but it looks like no one is making a really world-class motor for that speaker size. 

Hey...Maybe Andy W can answer this: The 6x9's in the ML Lexus LS's....what's the one-way linear xmax on those?


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## DS-21 (Apr 16, 2005)

Dangerranger said:


> Good to know, maybe I'll try to dig up an Ebay deal  Have heard them before but obviously never gutted them. If you still have them laying around, could you do me a favor and give an estimate on what the mounting cutout as well as mounting depth would have to be to use some of those little guys?


As it happens I had one under my desk, and they're super-easy to disassemble (pry off the grille, remove two hex bolts). It's shallower than I thought, about 2" with a small-diameter neo magnet. And the flange is a bit bigger, roughly 4" from corner to corner. Here are some crappy cellphone pics.



















Considering the cost of these things, IMO both the aesthetic and sonic performance is quite good.

This speaker is specifically an HTS1001.2.










(Oh, and the driver says 4Ω on it but the back of the egg says 6Ω.)



Dangerranger said:


> True. but from what I remember those drivers did have fairly impressive bass response for the size everything considered


Nah. They really just do that old LS3/5a thing of having really high Q sealed boxes to fool you into thinking they have bass at first.



thehatedguy said:


> Has anyone used the little Aurasound Cougars?


If you have any chance of fitting them, the Whispers are _much, much_ better.


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## thehatedguy (May 4, 2007)

You guys are gonna make me end up getting a divorce...lol. The wife doesn't understand it- my speaker and sound thing.

Crap...let me go see what I can do. Again.


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## Dangerranger (Apr 12, 2006)

DS-21 said:


> Nah. They really just do that old LS3/5a thing of having really high Q sealed boxes to fool you into thinking they have bass at first.


True. Keep in mind "all else considered" I should've mentioned my expectations aren't THAT high for a 3" driver  they do seem as if they'd do just fine 300hz on up in a vehicle on steep slopes.

And thanks for the pics, that flange does look pretty big I'll have to remeasure my dash spots. If I remember right the "tweeter" mounting holes are about 3 1/8" screw to screw with a 2 3/8" cutout 





DS-21 said:


> If you have any chance of fitting them, the Whispers are _much, much_ better.


Is it a miata that you run the whispers in? how do they do realistically? I know you said 700hz on up they do great I'm just wondering what to compare them to in terms of output level. I was debating trying out either those or the peerless 2" or 2.5" "fullrange" drivers


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## DS-21 (Apr 16, 2005)

Dangerranger said:


> True. Keep in mind "all else considered" I should've mentioned my expectations aren't THAT high for a 3" driver  they do seem as if they'd do just fine 300hz on up in a vehicle on steep slopes.


I think that's certainly doable. As for the back-side, I'd worry more about stuffing it well to fight backwave reflections than any bass loading, though. 

I also think there's no harm in running your midbasses higher than 300Hz. I set my midbass lowpass basically by upping the crossover until I lost that coherence, and then dialed it back until I got the coherence back. That led me to a point of 710Hz on the Alpine Audyssey box (H650). I suspect that I might be able to go a bit higher with the MS-8 when it gets here, because it can do 4th order slopes rather than just 2d order.



Dangerranger said:


> Is it a miata that you run the whispers in? how do they do realistically? I know you said 700hz on up they do great I'm just wondering what to compare them to in terms of output level. I was debating trying out either those or the peerless 2" or 2.5" "fullrange" drivers


I wouldn't say do great. I think people are surprised by how loud they can play, but there's certainly some distortion there. (I find the sound pleasing. The analogy I use is that they sound kind of like they're driven by a SET amp. Everything's clear but a little rose-tinted. Very pleasing for a casual listening system in a daily driver. (And very appropriate-sounding in my Miata's wood-and-tan-leather interior.) Perhaps not so great for someone interested in competition or with a great interest in a ne plus ultra critical listening system.

That said, from an excursion standpoint they're supposedly good for >102dB from ~350Hz up [edit: each] when fed their rated peak powerhandling of 60W. (At their continuous powerhandling of 15W they model out to ≥96dB from 350Hz up.) Do I think they can actually do that for any meaningful amount of time? No. But they do get pretty loud. Much louder than the 2" Peerless. (The Peerless '970 also doesn't have that "tubey" overload sound, being fairly cool until they audibly crap out.) Keep in mind that I'm a guy who likes to listen with the top down in a small open car with a fairly loud cat-back and have the system cranked loud enough to be able to hear, for example, the opening bars of Led Zeppelin's "No Quarter." And while I've been musing either commissioning pods for the upper doors (the stock Miata trim piece bolts onto the main doorcard) or doing A-pillars, the Whispers do well enough that in 6+ years of owning the thing I've never been that compelled to actually do it. (The KEFs are going to go across the front of my DS, if I ever get to that resto.)

Also, I was honestly surprised at how much louder they can get now that they're highpassed at 710Hz (2d order, with a second 2d order filter at 200Hz for excursion protection) than they could when I was running them at ~350Hz, 4th order with the SLS8's. According to Audyssey, the passenger side driver is 3.6' away from the first measuring point, and the driver side one is 2.4' away.

Worse comes to worst, they are available right now on eBay for 27 bucks a pair (caveat emptor, they may be knockoffs, and at any rate they only have the ones with the annoying solder pads, rather than the vastly nicer quick-disconnect tab ones, available. I asked.) so there's not much to lose.

At any rate, perhaps after these two hell weeks (I'm in the last throes of studying for the NY bar exam) you can take a listen if you're so inclined.


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## 14642 (May 19, 2008)

DS-21 said:


> Also, I was honestly surprised at how much louder they can get now that they're highpassed at 710Hz (2d order, with a second 2d order filter at 200Hz for excursion protection) than they could when I was running them at ~350Hz, 4th order with the SLS8's. According to Audyssey, the passenger side driver is 3.6' away from the first measuring point, and the driver side one is 2.4' away.


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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## wadejg (Apr 20, 2007)

I just spent days listening to a whole bunch of 1"-3" full range drivers. I listened to 25 drivers total, and did a couple reviews in that section of the forum. I was pretty surprised at the quality that one could get, especially when they were crossed over at 300hz+. However, in the end, when a tweeter was added (and crossed over) the level of detail increased and distortion was clearly less, no matter how flat the response curve was supposed to be of the full range driver I was listening to. It was enough of a difference to convince me that I will likely run my center channel with a tweeter crossed over passively.

What was also clear, was that the drivers that sounded best run full range, were also the ones that sounded best when a tweeter was added. I thought perhaps some of the drivers might have coloration at higher frequencies that when crossed over and a tweeter was added would be less noticeable, but this was absolutely not the case.

Regards,
Justin


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## Dangerranger (Apr 12, 2006)

kkant said:


> From the specs, it looks like the Scan 18W's will kill the Kef and JBL 6x9's in midbass, despite the smaller cone area. I'd love to try a good 6x9, it would fit perfect in my ride, but it looks like no one is making a really world-class motor for that speaker size.


Realistically I highly doubt it in a car. The Scan 18W has a very good motor, but realistically I wouldn't say it's so much better than the JBL that it'd make up for the difference in surface area. It's been a while since I've toyed with a T595, but they had a very beefy motor on that one, definitely looked to be more an adaptation or at least very similar to their pro drivers of the era. Perhaps that's a bit assumptive, but keep in mind this is a company that had sophisticated motor designs LONG before Scanspeak was even created as a company. Hell they were using optimized overhung motors and SILVER shorting rings in drivers that they built 30 years ago. The mids and tweeters weren't the absolute greatest in the world, but they were pretty good all considered, but that midbass driver was just awesome.

Aside from that, most of the 18Ws I've heard in car applications weren't particularly fantastic in a car door without a good bit of tuning just due to the motor and suspension design on them. They get low, but from a more practical perspective in the 80hz-160hz region or so there was a bit to be desired. I couldn't tell you what the X-max was on the T595, perhaps andy has an older spec sheet laying around with more details on the drivers, but they were VERY efficient, the Qts wasn't so low that it was thin on the low end, but in terms of absolute tactile bass output and tonal balance I've heard few midbasses that can match it.


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## tonym (Jun 21, 2009)

I have a grand cherokee ...there isnt any room for a center..only place would be down by the shifter..I run AVI they have a 2 speakers that will fit...

1st
FRM-70, 70 mm (2.5") Full Range Device 
Serious disbelief was the first reaction from audiophiles with this little full range. To date, nothing has emerged from the market that has the capability of high quality sound production from something this compact. It is the most powerful 2.5" Full Range Device in the market (45 W RMS), thus making it a good center channel speaker. With a cast aluminum frame, 1" voice coil, and a neodymium magnet and the operating range is suggested at 110 Hz to 26 KHz. 

2nd 
MDN-50, 50 mm (2") Dome Midrange Device 
Believe it or not, the MDN-50 is a midrange device! It is powered by a 72g (2.5 oz) neodymium magnet and a 50 mm (2") aluminium voice coil with a suggested operating range of 550 Hz to 13 KHz

waste of time? or would there be a noticeable diferance?


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## WLDock (Sep 27, 2005)

Andy Wehmeyer said:


> 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.
> The center is a similar dual-2-ohm 6" and a tweeter and it's mounted in the top of the dash.


OK, thanks for clearing that up...I was wondering how you pulled off 3-way L & R, center, rear, sub. But, I guess you are not running rears?

Myself, I was wanting to try rears but I wanted to try 3-way L & R as well. I guess I have time to figure it out....I will keep reading the experiences of others for now.


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## hallsc (Oct 26, 2008)

3-Way L + R, Rears, Center, and Sub are attained through the use of a passive crossover between the mids and the tweets. I had this question about a month ago on the big MS-8 thread. Obviously the center is passively crossed as well.


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## MarkZ (Dec 5, 2005)

Can't wait for the MS-13 to come out. 

I really don't see the point of using passives + components instead of simply using coaxials, UNLESS you're going to provide attenuation/L-pad or get creative with the passive crossover. There are lots of very capable coaxial speakers out there for cheap. In this forum we usually ignore them, usually because it's hard to mount a sizable midrange up high. But I think there's also a stigma attached to coaxials in certain parts of car audio land. Just sayin...


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## mitchyz250f (May 14, 2005)

Andy, I think you said passives could be used when the mid and the tweet were close. What does close mean? Is that actual distance from mid to tweet or path length? My mids and tweets are in my pillars, the tweeters are 5" further away. Can I use passives. If my mids are in my lower doors but have the same PL as the tweets in the pillars, is that considied close. 

Also, is the center more important than the rears?

Mark- I think the coaxials are a good point. Can you recommend some?


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## Knobby Digital (Aug 17, 2008)

MarkZ said:


> Can't wait for the MS-13 to come out.


It already has. And fools are so crazy about it, they're getting it tattooed all over their bodies.


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## 89grand (Nov 23, 2006)

MarkZ said:


> Can't wait for the MS-13 to come out.
> 
> I really don't see the point of using passives + components instead of simply using coaxials, UNLESS you're going to provide attenuation/L-pad or get creative with the passive crossover. There are lots of very capable coaxial speakers out there for cheap. In this forum we usually ignore them, usually because it's hard to mount a sizable midrange up high. But I think there's also a stigma attached to coaxials in certain parts of car audio land. Just sayin...


I don't get it either. When I do my system, it will be midbass in the doors (factory location) L/R 4" coaxials on the far corners of the dash near the wind shield (factory location) and one 4" coaxials in the center of the dash (not factory). I see no advantage to using a component set over a coaxial in my application.

I could see some limitations with a small wideband, but not with a 4" coaxial.


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## DS-21 (Apr 16, 2005)

MarkZ said:


> But I think there's also a stigma attached to coaxials in certain parts of car audio land. Just sayin...


I for one would _never_ pick a separate MT over a well-designed coaxial.


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## MarkZ (Dec 5, 2005)

Yup. But amp crossovers rule, so that could save the day if you've got them and the extra channel to work with. That's probably the only reason I'd go with discrete components... so that you can adjust tweeter level & crossover point. But aside from that, decent coaxials should do just fine.

--Edit: I forgot this was an MS-8 thread and that it will just undo what you tweak at the amp anyway  --

Anyway, it's all a moot point for me. Andy can rake me over the coals, but I don't use a tweeter for my center.  My center mids flirt with 6kHz. I'm not yet convinced that I'm missing out on much by leaving out the last octave and a half...


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## kkant (Feb 3, 2008)

Dangerranger said:


> Aside from that, most of the 18Ws I've heard in car applications weren't particularly fantastic in a car door without a good bit of tuning just due to the motor and suspension design on them. They get low, but from a more practical perspective in the 80hz-160hz region or so there was a bit to be desired.


What specifically do you mean? We have the MS8, so any linear aberrations associated with mismatched Qts/Vas etc will be corrected (not to mention most of the FR problems in that range are related to the shape of the car, not the driver). On nonlinearities, well, if the JBL 6x9's have about the same cone area as other 6x9's, and they are about 3mm xmax (the figure I see associated with the KEF 6x9s y'all have mentioned), then the Scans have a full 50% more linear displaced volume than the JBL 6x9s. Despite the smaller cones. That's a big difference, and it's something the MS8 can't compensate for.


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## WLDock (Sep 27, 2005)

hallsc said:


> 3-Way L + R, Rears, Center, and Sub are attained through the use of a passive crossover between the mids and the tweets. I had this question about a month ago on the big MS-8 thread. Obviously the center is passively crossed as well.


You know....that is what I was thinking but it seems like a step backwards imo. I know the MS-8 can correct a lot of problems but I doubt it can fix the all the issues of a bad designed crossover. Once I went active almost two decades ago....I never wanted to deal with passives in a three-way system again.

*On the other hand, I see no reason to get an MS-8 unless I plan to run a center and rear....what would be the point?*

Well, I guess I will keep working on some designs. The plan is to run some tweets and 3" mids that have high efficiency so....maybe I can come up with an all active system using a combo of the internal amps combined with outboard amps and active crossovers....maybe just passives on the mid/tweet? An all out system will need 14 drivers to pull it off!

This is going to take some time just to design! Heck, my OEM system has 9 drivers with 2.5" coaxials in all the doors and one in the center of the dash. My car is perfect for the MS-8 I am going all out or bust!


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## kkant (Feb 3, 2008)

WLDock said:


> On the other hand, I see no reason to get an MS-8 unless I plan to run a center and rear....what would be the point?


The autotune.


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## Dangerranger (Apr 12, 2006)

kkant said:


> What specifically do you mean? We have the MS8, so any linear aberrations associated with mismatched Qts/Vas etc will be corrected (not to mention most of the FR problems in that range are related to the shape of the car, not the driver).


This is true, I wasn't referring to their use with an MS-8. MS-8 or not though, I'd rather the low end response be closer than not just due to not having to EQ the crap out of a driver and mess with your amplifier headroom. Your amplifier is only as powerful as how much is left after the highest level of boost is applied unless someone enjoys distortion



kkant said:


> On nonlinearities, well, if the JBL 6x9's have about the same cone area as other 6x9's


Probably just a tad more surface area just due to not having any polepiece or phase plug or similar in the way, but that won't affect the surface area a ton. I'd estimate it's similar to others, probably 220cm^2 or so versus the Revelator 7" being 150cm. Their newer T696 6x9 has 237cm^2 surface area but it has the Plus one cone design which gives a tad more surface area. I'm not sure of the x-max of the T595s but the output was a lot more than the KEFs, and the motor was a lot more substantial. The KEFs were good, but the bass output wasn't the selling point, concentric drivers just make a whole lot of sense in car audio. Not that the motor/suspension wasn't well designed either, just not the highest output drivers out there. Hopefully andy or someone could chime in on the T595? I'd bet they're more than 3mm one way honestly.



kkant said:


> and they are about 3mm xmax (the figure I see associated with the KEF 6x9s y'all have mentioned), then the Scans have a full 50% more linear displaced volume than the JBL 6x9s. Despite the smaller cones. That's a big difference, and it's something the MS8 can't compensate for.


They don't inherently have anything. Saying a driver has 50% more displaced volume is like saying speakers produce 300 watts rather than handle them. It's simply potential. The excursion is a matter of the frequency produced and the power applied to the driver, and how efficient the driver is. And the interaction with the enclosure if applicable. So the real question is: in the real world, in the given application, can you actually utilize said driver in a way that would realize this potential and have it outperform the other driver in question? The Scanspeak doesn't have any more output than a lower x-max 7" until you dump enough power on it to realize the potential. That JBL is 6-7db more efficient than the Scanspeak off the jump. So you're going to have to dump 4x the power on the Revelators just to get a comparable output level. It'd be like saying an Aurasound Cougar is capable of more output due to having more "displacement" than a conventional dome tweeter, after all, the x-max is there  Just doesn't work that way in the real world, hoffman's iron law is a mofo.

What the Scanspeak could do is drop lower, but honestly my criteria for a midbass driver isn't whether it can drop to 40hz in a door, not sure if that's one of yours or not. It's unrealistic to use a 7" driver down that low, the distortion is going to be terrible as well as a car door being a crappy enclosure to begin with. 80hz is about all I want to run a 7" down to, 60hz if I don't require high-ish output levels.

Displacement potential is important, but if you have the chance to maximize surface area versus maximizing excursion out of a smaller driver for the exact same displacement, the latter is never an acceptable compromise IMO. Displacement potential is exactly that: potential. Surface area is a constant, x-max is a variable based on a lot of different things factoring in and it's not in any way guaranteed output. Then you have issues like power compression, the voice coil/suspension of a driver is never centered, most of the time a few mm off even with better manufacturers. Inductance variation is higher shorting rings or not. And on top of that, a large x-max doesn't guarantee low midbass distortion. If that were the case the Adire Audio extremis would be the midbass king of the 7" driver world and it's just not so. Metal and Kevlar coned drivers tend to rule the roost in low midbass distortion.


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## kkant (Feb 3, 2008)

Dangerranger said:


> This is true, I wasn't referring to their use with an MS-8. MS-8 or not though, I'd rather the low end response be closer than not just due to not having to EQ the crap out of a driver and mess with your amplifier headroom. Your amplifier is only as powerful as how much is left after the highest level of boost is applied unless someone enjoys distortion


The minor difference in midbass responses due to the T/S mismatch is simply not enough to justify a decision either way. The car interior has a far larger impact on the linear response in the midbass.



Dangerranger said:


> They don't inherently have anything. Saying a driver has 50% more displaced volume is like saying speakers produce 300 watts rather than handle them. It's simply potential. The excursion is a matter of the frequency produced and the power applied to the driver, and how efficient the driver is. And the interaction with the enclosure if applicable. So the real question is: in the real world, in the given application, can you actually utilize said driver in a way that would realize this potential and have it outperform the other driver in question? The Scanspeak doesn't have any more output than a lower x-max 7" until you dump enough power on it to realize the potential. That JBL is 6-7db more efficient than the Scanspeak off the jump.


********, no way. 97 db sensitivity? Not counting the coax mid/tweet? Remember the coax doesn't do anything at the midbass range. I can grant you a 2-3 db sensitivity advantage for the 6x9. So yes, you need more amp power on the Scans to realize the full xmax. First of all I would say, amp power is as cheap as you want it. Non-issue. Second, on power compression, yes it's an issue. But it's not as simple as you make it out to be. A less sensitive driver may be designed in such a way as to have less power compression than the higher sensitivity motor -- say due to heavier and better heatsinking off the coil, just to name something that pops into mind.

And why not increase the cone size indefinitely? Breakup and directivity. There are disadvantages to a bigger cone; and I would want to see real world measurements before jumping to the conclusion that an oval speaker inherently has better breakup characteristics. Unfortunately such measurements seem to be very hard to find for ovals.



Dangerranger said:


> What the Scanspeak could do is drop lower, but honestly my criteria for a midbass driver isn't whether it can drop to 40hz in a door, not sure if that's one of yours or not.


Not at all. I fully agree that 80 is the minimum to take a pair of 7's to. Actually I would say 100 min on the 7's, for the reasons you suggest. But saying that the Scans play lower is really equivalent to saying that they will play louder more linearly, at any pistonic frequency. Including midbass above 100. And that's what I am looking for.



Dangerranger said:


> Displacement potential is important, but if you have the chance to maximize surface area versus maximizing excursion out of a smaller driver for the exact same displacement, the latter is never an acceptable compromise IMO.


If the displacements were the same, I would probably agree with you. But they are not. Not even close. The Scan is significantly higher. And this doesn't even consider the demonstrably low nonlinear distortion of the Scan motor, within its "linear" xmax limits.

Here's how I see it. If you compare the optimal system design using Scans against the optimal system design using 6x9's, the Scans win on output and linearity. It may be more expensive, but it'll be better.



Dangerranger said:


> Metal and Kevlar coned drivers tend to rule the roost in low midbass distortion.


Actually, according to Zaph, what rules the roost in midbass is the Scan Revs. Not the metal/kevlar drivers.


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## Dillyyo (Feb 15, 2008)

Andy Wehmeyer said:


> 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.
> 
> ...


Does this midrange discussion equally apply to cones and dome drivers? I am currently set up like you, but have 10's in the doors with 3's and tweets in the upper door and sails respectively. I think my G37 can fit a 3" dome in the center, but my midranges are LP at ~500 IIRC.


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## Dangerranger (Apr 12, 2006)

kkant said:


> ********, no way. 97 db sensitivity? Not counting the coax mid/tweet?


94db sensitivity. The 4 ohm scan is advertised as 90db, but that's at 2.83V (2 watts with a 4 ohm load). Both the 8 and 4 ohm scans are 87db. 



kkant said:


> Second, on power compression, yes it's an issue. But it's not as simple as you make it out to be. A less sensitive driver may be designed in such a way as to have less power compression than the higher sensitivity motor -- say due to heavier and better heatsinking off the coil, just to name something that pops into mind.


To which I'd argue that a higher sensitivity driver could also be designed to dissipate heat just as effectively. JBL has been a good example of that with their pro audio equipment for a good long time.



kkant said:


> And why not increase the cone size indefinitely? Breakup and directivity. There are disadvantages to a bigger cone; and I would want to see real world measurements before jumping to the conclusion that an oval speaker inherently has better breakup characteristics. Unfortunately such measurements seem to be very hard to find for ovals.


We were referring to midbass and overall linear displacement after all, I'm not at all arguing the effectiveness of Scans as an overall solution



kkant said:


> But saying that the Scans play lower is really equivalent to saying that they will play louder more linearly, at any pistonic frequency. Including midbass above 100. And that's what I am looking for.


Not necessarily. Playing louder would be if you could realize the potential of it's excursion, which is dependant on the frequency range you're trying to cover. A 6" midrange will get a whole lot louder than a 6" midbass in it's intended range in a real world application just due to the aforementioned reasons of power compression and efficiency, despite the midbass having more linear excursion potential.



kkant said:


> If the displacements were the same, I would probably agree with you. But they are not. Not even close. The Scan is significantly higher. And this doesn't even consider the demonstrably low nonlinear distortion of the Scan motor, within its "linear" xmax limits.


Again you're assuming that this JBL is the typical garbage 6x9 offering like 99% of those offered to the car audio market. 




kkant said:


> Actually, according to Zaph, what rules the roost in midbass is the Scan Revs. Not the metal/kevlar drivers.


By Zaph's own testing the SEAS Excel W18EX is a good bit cleaner than the Scan in midbass distortion, actually anywhere below 500hz, with them being pretty even up to around 1khz which is the point that you have to worry about harmonics exciting the breakup node on the mag cone. And comparatively, the W18EX is actually cleaner than the W18NX in midbass distortion despite the NX having SEAS more recent implementation of the Excel motor platform. Scans own Kevlar drivers were also cleaner down low as well, though, as are Usher's Scan 8545 clone

As far as others, the results seem to be similar. Linkwitz decided on the Excel W22 over the Scans for the same reasoning, when he was testing for the Phoenix dipole system, the W18E Excel was very close to Scans 8" drivers. After that SEAS released the W22 driver which Linkwitz decided to use in his Orion design due to wanting a low distortion 8" driver without utilizing a multiple driver arrangement.


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## kkant (Feb 3, 2008)

Dangerranger said:


> 94db sensitivity. The 4 ohm scan is advertised as 90db, but that's at 2.83V (2 watts with a 4 ohm load). Both the 8 and 4 ohm scans are 87db.


You're right, I missed that. But I'm still not going to grant you a 7 db sensitivity difference. I'm sure that's either due to differences in measurement or because of the coax drivers adding to the SPL at some higher frequency. The cone area you quoted was only 1.5x the 6", and I doubt the motor is *that* much more sensitive--especially when it has to carry the higher mass of the bigger cone. I'm sticking to a 2-3 db difference until I see some real tests. 



Dangerranger said:


> To which I'd argue that a higher sensitivity driver could also be designed to dissipate heat just as effectively. JBL has been a good example of that with their pro audio equipment for a good long time.


Again, I doubt it. Sure, it could be incredibly high sensitivity and also great heat dissipation all at the same time--and why not let's throw in huge xmax and ruler flat response. Given that we lack information about this 6x9, that's not the right assumption to make. It's almost always a compromise.



Dangerranger said:


> Not necessarily. Playing louder would be if you could realize the potential of it's excursion, which is dependant on the frequency range you're trying to cover. A 6" midrange will get a whole lot louder than a 6" midbass in it's intended range in a real world application just due to the aforementioned reasons of power compression and efficiency, despite the midbass having more linear excursion potential.


That's a real broad statement and generalization, especially in the absence of data. Could be this, could be that, who knows? So we're back to the question of how loud and clean these drivers get in the midbass. I'm betting that both the Scans and 6x9's have no problem reaching xmax without significant power compression problems. In which case, the Scans win. In the absence of data, that's a fair assumption.



Dangerranger said:


> By Zaph's own testing the SEAS Excel W18EX is a good bit cleaner than the Scan in midbass distortion, actually anywhere below 500hz, with them being pretty even up to around 1khz which is the point that you have to worry about harmonics exciting the breakup node on the mag cone. And comparatively, the W18EX is actually cleaner than the W18NX in midbass distortion despite the NX having SEAS more recent implementation of the Excel motor platform. Scans own Kevlar drivers were also cleaner down low as well, though, as are Usher's Scan 8545 clone


I took a look at the graphs again, and you're right. That Seas is a nice driver. Still, I don't think I would use it in my application -- though the midbass distortion is excellent, the 1.7k nonlinear out-of-band peak is pretty bad--even if I cut it off at 1.2 I can still see that causing a problem. That's a sensitive range for our ears. And MS-8 can't fix that problem.


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## Dangerranger (Apr 12, 2006)

kkant said:


> You're right, I missed that. But I'm still not going to grant you a 7 db sensitivity difference. I'm sure that's either due to differences in measurement or because of the coax drivers adding to the SPL at some higher frequency. The cone area you quoted was only 1.5x the 6", and I doubt the motor is *that* much more sensitive--especially when it has to carry the higher mass of the bigger cone. I'm sticking to a 2-3 db difference until I see some real tests.


Realistically the Scan is designed with a low Fs due to being designed for ported use in home cabinets. An Fs of 27.5 is REALLY low for a 7" driver, and it's due to a very loose suspension as far as the Scan goes (look at the Vas and Qms). That's to compensate for the BL being lower for multiple reasons, having a lot of copper in the motor cuts down on your BL force a good bit just because the gap can't be as tight. Longer excursion cuts efficiency just due to the moving mass of having more coil. While I'm a big proponent of shorting rings, you also have to realize that there are things that you have to compensate for when they're used. It's always a tradeoff. I'm not really sure if the JBL has shorting rings or not, they definitely had shorting rings in most of their pro drivers at that point but not sure if the 595 got the trickle-down from that.

Just because you're driving a larger cone doesn't mean that the motor is less sensitive. Larger drivers get larger motors to compensate for the moving mass, but on the other hand you have proportionally higher radiating area. The real question is: say you compare an 8" driver to a 7" driver like the Scan, if it has 1.5x the surface area yet doesn't have 1.5x the moving mass, it's a given it's going to be more efficient if the motors are geared to generate the same parameters. Low bass response is a function of Fs vs Qts. You can get any driver to drop low, it's just a question of whether you're willing to make the compromises to get it. Just as a 1" Aurasound Cougar driver can drop lower than a 1" tweeter, but that 78db sensitivity isn't going to do much no matter how much power you dump on it. Now, you get into compromise. With an 8", most are going to design it to have lower bass response than the 7", just because it's easy to and people would expect that. But if they're designed to produce the same frequency range, the 8" is going to be much more efficient. 

As far as the JBL goes, it was a lower Q design and wasn't a terribly low Fs like the Scanspeak is. It's a given that's going to be more efficient especially considering the additional cone area. If the Scan were designed the same way it would also be more efficient. Where the Scan can drop low, I feel it's not particularly beneficial in an environment where transfer function offers so much help in that region. I don't feel that it justifies the loss in efficiency. 100-300hz is the big problem area in the vehicle and it doesn't take a monster excursion driver to cover that, but efficiency definitely does help. You can always make a driver quieter . After you equalized that Scan in the intended frequency range, you'd be surprised just how little of that excursion you're using. And if you don't have a ton of power on it, you're not using it anyway. Pushing that driver in a home in a sealed or ported enclosure with 100 watts at 50hz is one thing, pushing it in a vehicle with 100watts and a 80 or even 100hz HPF is totally different. There isn't really as much excursion required of said drivers as people make it out to be, most of the time the distortion people complain about are simply them pushing their amplifier into clipping or people just using too low a crossover frequency on a crap driver.

One could technically use a W7 or a TC sounds LMT motored subwoofer in an SPL competition as well, but the power just isn't there to utilize their excursion in a ported enclosure. If the competition set a requirement that all subs competed at 20hz it'd be different. Sometimes monster excursion and lower efficiency is a hindrance, same goes when you're using a higher crossover frequency, which with lower surface area drivers in a car for midbass, I'd call a necessity.



kkant said:


> Again, I doubt it. Sure, it could be incredibly high sensitivity and also great heat dissipation all at the same time--and why not let's throw in huge xmax and ruler flat response. Given that we lack information about this 6x9, that's not the right assumption to make. It's almost always a compromise.


Of course. But every speaker is a compromise, the Revelator included. But in terms of an all around 7" driver that does everything well, Scanspeak did make the right compromises. That's not to say it's the ultimate in every single thing, but it's damn good. It doesn't have the midbass performance of the W18EX nor does it have the upper midrange performance of the (discontinued and missed by me at least) the Vifa XG, but it's a solid implementation.



kkant said:


> That's a real broad statement and generalization, especially in the absence of data. Could be this, could be that, who knows? So we're back to the question of how loud and clean these drivers get in the midbass. I'm betting that both the Scans and 6x9's have no problem reaching xmax without significant power compression problems. In which case, the Scans win. In the absence of data, that's a fair assumption.


Well realistically a dedicated midrange design will differ from a dedicated midbass design a lot unless the designer is just pulling the wool over someone's eyes. Scan has a dedicated midrange revelator in 5" form and if you compare that with the 5" midbass, (midrange: 15M/4531K, midbass: 15W/4531G) it's 3db more efficient in the same surface area. In their case they accomplished it by a lower Qts, lower moving mass due to cutting the x-max in half. And realistically the Fs isn't much higher than the midbass, they really could have gotten even more efficiency out of the midrange if they wanted. Look at the old JBL 2118. 8" midbass driver, higher Fs, low Qts. Not designed to go as low as the drivers we're talking about, but has a solid 97db sensitivity. When you don't have to design a driver to drop really low, you open up a lot of doors. That driver could drop to 70hz in a ported cabinet. In a car, when you have transfer function working in your favor you have to ask the question: How low do you REALLY need to go? The same argument exists for subwoofers realistically, where people complain that drivers with more low end sound boomy and sloppy when they havent' applied enough EQ to compensate for it.



kkant said:


> I took a look at the graphs again, and you're right. That Seas is a nice driver. Still, I don't think I would use it in my application -- though the midbass distortion is excellent, the 1.7k nonlinear out-of-band peak is pretty bad--even if I cut it off at 1.2 I can still see that causing a problem. That's a sensitive range for our ears. And MS-8 can't fix that problem.


Exactly. I prefer to use it in a home where you can get tweeters that can mate up with it. Or midranges. I'm definitely not arguing the effectiveness of the Scans as an overall driver. The only hindrance to it's top end are simply beaming issues inherent in any 7" driver. It's a very easy driver to work with and very effective.


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## Dangerranger (Apr 12, 2006)

But I agree that this argument is not going far as we lack information on the older JBL. I've scoured their older files for more information with no luck 

Perhaps we could have a shootout with drivers that we do have readily available for testing: say the Scan versus the ID XS69? Both in linear output potential, and in a real world implementation with differing power levels, crossover frequencies, etc?


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## kkant (Feb 3, 2008)

Dangerranger said:


> Perhaps we could have a shootout with drivers that we do have readily available for testing: say the Scan versus the ID XS69? Both in linear output potential, and in a real world implementation with differing power levels, crossover frequencies, etc?


That would be very helpful. I would actually like to find a 6x9 which would be "as good as" the Scans from 100-1200 Hz. Apart from anything else, it would make installation easier.



Dangerranger said:


> As far as the JBL goes, it was a lower Q design and wasn't a terribly low Fs like the Scanspeak is. It's a given that's going to be more efficient especially considering the additional cone area. If the Scan were designed the same way it would also be more efficient. Where the Scan can drop low, I feel it's not particularly beneficial in an environment where transfer function offers so much help in that region. I don't feel that it justifies the loss in efficiency. 100-300hz is the big problem area in the vehicle and it doesn't take a monster excursion driver to cover that, but efficiency definitely does help.


I'm still reading the rest of your post, but this struck me first. I do think I am using most of the excursion, even crossed at 100 Hz. Perhaps I listen louder then most. But I expect each driver to be capable of 110 db at about 10% distortion. And for a 6-7" at 100Hz, that requires a lot of xmax.


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## radarcontact (Oct 28, 2010)

Hate to bring a dead thread back to life, but this is SO frikin' interesting...wish I had just a tad more grey matter...

Anyway - if "dash-pointed-up-at-windshield" is impractical for my vehicle, how bad would "attached-to-back-of-rearview-mirror-pointing-parallel-to-dash" (straight out the damn windshield) be? I realize this effectively bounces the sound _onto _the dash from above, but wouldn't that also give a decent "airyness" for a center channel?


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## cycfari (Jan 9, 2009)

After reading all the wonders of the center channel, I took the plunge too & made a diy center speaker from a little flower pot. Sealed enclosure is approx. 0.8L ,Driver is 3" fullrange Fountek FR89EX. Looking foward to install & test it soon.


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## quietfly (Mar 23, 2011)

this is a great thread!


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## eviling (Apr 14, 2010)

I playyed with a single L4 as a center back when i was gonna use L4's for A pillar, I din't really find a HUGE difference with a center period, its a compliment to any music, but really never heard a WOW OMG moment.


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## FG79 (Jun 30, 2008)

I came across this thread by accident, and it definitely interests me because I've been a center channel guy myself.

How are people liking the MS-8 with the center??

I'm lost exactly on how the MS-8 processes the center....I read a little bit of Andy's post but it seems like all the speakers are being processed at once as opposed to just manipulating the center??

This concern of getting a very low crossover point to match the side woofers really amazes me because I was doing just fine with a crossover point of 150 hz on a 4" coax! Everything was passive in the system, no processing....and as long as you were below 300 hz, everything was good. 

You didn't need 80 hz from a 4" driver as the rest of the system was providing that. And the system was coherent too as in it sounded like you were getting full range from the center. It also added midbass and midrange punch to the system. A 6.5" driver is nice, but seems unnecessary.

The hard part is that it didn't discriminate as a center, so most of the image was sucked to the middle. Great for vocals, but sometimes instruments would get tugged there as well. Compromise.

What I always wanted was just to manipulate the center to only play what was common to both channels and ignore the sounds that were individual to left and right channels! Why can't we have a processor (or processing mode) that does just this? Even if it wasn't perfect, it'd be awesome. 

It may work as is from an imaging/staging point right now, but I'm worried about how tonality will be affected. I want total freedom to do what I want to do with the rest of the drivers (in particular crossover points)....manipulate the center as needed. 

BTW: Upward facing, bouncing off the windshield did the job just fine. No need for exotic angles.


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## subwoofery (Nov 9, 2008)

FG79 said:


> I came across this thread by accident, and it definitely interests me because I've been a center channel guy myself.
> 
> How are people liking the MS-8 with the center??
> 
> ...


:blank: You should really re-read how the MS-8 processes the center channel. Do a search, your wanted processor does exist already... 

Kelvin


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## FG79 (Jun 30, 2008)

subwoofery said:


> :blank: You should really re-read how the MS-8 processes the center channel. Do a search, your wanted processor does exist already...
> 
> Kelvin


I'm a skeptic when it comes to car audio these days, but believe me I want such a product to exist.

I'll PM Andy.


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## CraigE (Jun 10, 2008)

Maybe this will help.
Page 87, post #2151, Giant MS-8 Thread

http://www.diymobileaudio.com/forum.../8257-jbls-ms-8-processor-87.html#post1002963


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## 14642 (May 19, 2008)

FG79 said:


> What I always wanted was just to manipulate the center to only play what was common to both channels and ignore the sounds that were individual to left and right channels! Why can't we have a processor (or processing mode) that does just this? Even if it wasn't perfect, it'd be awesome.


This is precisely what Logic7 does with a center channel.


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## boulderguy (Oct 2, 2011)

I made it thru 3 pages, now I'm just lazy & asking - 

What's the general opinion about matching center channel power to L & R power?

Specifically, if I have 6.5" satellites & a 5.25" center (X'ed at say 80), and the sides have 100w each, can I get away using the MS8 amp for the center @ 20w, or do I need another 100w for the center?


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## FG79 (Jun 30, 2008)

Andy Wehmeyer said:


> This is precisely what Logic7 does with a center channel.


Ok, I looked at your original post with the diagrams and all...

It seems like the L7 will filter out bass from the door speakers and then put that on the center to play. I get what is trying to be achieved here and I'm sure it images very nicely but I'm worried that this processing will take away the dynamics and overall midbass of the system. 

I hear this type of tradeoff too often in cars, and because I'm not an imaging/staging audiophile like everyone else it's not a reasonable tradeoff for me.

I'd love to be proven wrong in a big way (that midbass/dynamics are as good or better), because I'm a center channel guy. 

Where are the L7 demo cars?


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## subwoofery (Nov 9, 2008)

FG79 said:


> Ok, I looked at your original post with the diagrams and all...
> 
> It seems like the L7 will filter out bass from the door speakers and then put that on the center to play. I get what is trying to be achieved here and I'm sure it images very nicely but I'm worried that this processing will take away the dynamics and overall midbass of the system.
> 
> ...


Why do you think that the bass is filtered out the bass from the front speakers? Where did you read that? 

Kelvin


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## boulderguy (Oct 2, 2011)

I think he's looking at this from the MS8 thread - 



Andy Wehmeyer said:


> 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.


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## tarkusnj (Sep 21, 2016)

So how did this center channel speaker perform?


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