# Audiomobile MASS subwoofers



## Skierman (Mar 3, 2008)

Does anyone have any information or opinions on those drivers?


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## chijioke penny (Mar 22, 2007)

it's a pretty good sub....i owned two MASS 12's and loved them (sold them to get the ID MAX's)....I heard that tc sound made them for audiomobile


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## DS-21 (Apr 16, 2005)

chijioke penny said:


> it's a pretty good sub....i owned two MASS 12's and loved them (sold them to get the ID MAX's)...


Wow, that's a _gigantic_ step down. Why would you go from a SOTA underhung driver to a generic one?

When Audiomobile went under (or at least stopped buying drivers) they ended up in SVS Ultra home subs...

(The Audiomobile Mass's precursor, a driver sold by Crystal Sound - and used by TN for his I-B home setup - and Rudi Blondia of Audio-X-Stream, was also quite a phenomenal driver. Really put TC Sounds on the map.)


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## mvw2 (Oct 2, 2005)

Different strokes for different folks.

Anywho, the Search button will yield a few past discussions on the MASS sub. Search around, see what you find, and then come back here with any specific questions you may have.


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## machinehead (Nov 6, 2005)

I sold a pair of idq's to pick up a mass back in the day. Ported it, slapped a jbl 600.1 on it. Those were good times. Really helped jumpstart the whole online sub bussiness.


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## Robert_J (Nov 9, 2006)

DS-21 said:


> When Audiomobile went under (or at least stopped buying drivers) they ended up in SVS Ultra home subs...


 And at first, they were a direct copy with a different color cone (and maybe different T/S parameters). Then TC/SVS went to the Eclipse style basket but kept the motor the same. My SVS Ultra with the Eclipse basket has a magnet boot. When you remove it, there is an Audiomobile serial number sticker on the magnet.

Donpisto has a pair of 12", TC Sound built, underhung drivers in the for sale section. As close to Audiomobile as you can get.

-Robert


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## Eric Stevens (Dec 29, 2007)

DS-21 said:


> Wow, that's a _gigantic_ step down. Why would you go from a SOTA underhung driver to a generic one?


SOTA? that is a subjective opinion not many will agree with. It offered good performance for the price when first offered for sale. 

It was a long coil tall gap motor NOT under hung. 

What is generic about an IDMAX? Maybe you can explain with some insightful wisdom 

Eric 
Image Dynamics


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## Neil (Dec 9, 2005)

The MASS was an underhung driver that used a full sleeve on the pole (or a shorting ring below the gap...can't remember anymore) to further reduce, and improve the linearity of, the MASS's inductance. It really was (and still is) a great driver with better engineering behind it than even some of the popular drivers mentioned in this thread....

There is a reason the MASS is still talked about despite Audiomobile drivers being non-existent for many years now.


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## DS-21 (Apr 16, 2005)

Eric Stevens said:


> SOTA? that is a subjective opinion not many will agree with.


You are perhaps aware that the substantive meaning of "many" is simply "more than one." That is to say, no different from the meaning of "some," as opposed to "most," which means "more than half." So your diction is quite revealing, even if perhaps you did not intend it to be so. 

Sure, there may be any number of people who do not think that a long-throw underhung driver with low inductance due to Faraday shielding was not SOTA then (or now). They would be wrong.



Eric Stevens said:


> It was a long coil tall gap motor NOT under hung.


Perhaps they had multiple models and we're both basically right, but there certainly was a variant of the old TC-made Crystal/Audio-X-Stream underhung driver sold under the Audiomobile Mass brand name. 



Eric Stevens said:


> It What is generic about an IDMAX? Maybe you can explain with some insightful wisdom


The danger of a manufacturer asking such a question is that some of us are perfectly willing to answer it!

Correct me if I'm wrong, but given your literature one has to assume the IDMAX just a (very expensive) conventional overhung woofer lacking: 
-treatment of the coil, gap, or pole to linearize BL over excursion
-no Faraday shielding to lower inductance and limit inductance variation [edit]over excursion[/edit]

Moreover, despite obviously having the capability to measure it (given LEAP graphs in the product lit) you don't even bother to tell consumers what the inductance of the driver is. That marks you right away as, in the most positive interpretation, lacking interest in offering product that will be of interest to people who actually know anything.

Also, frankly by modern standards it offers a pretty short throw for the money. And the thing is tarted up with a gigantic and ugly logo on the cone. 

Don't get me wrong, your ur-IDQ's were perfectly competent drivers when they first came out. As you may remember, you graciously replaced an IDQ-12 for me after I measured one that I had bought in 1997 or early 1998 and found its T/S parameters to be wildly out-of-spec when I measured it in Dr. Marshall Leach's audio lab at GA Tech. But you guys should really look at modernizing your lines.


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## thehatedguy (May 4, 2007)

Shorting rings in subs really have little effect on the speaker's performance from the couple things that I have read...effect in the area the sub is being used at.


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## ANT (Oct 15, 2005)

DS-21 said:


> Wow, that's a _gigantic_ step down. Why would you go from a SOTA underhung driver to a generic one?


Generic?
From my understnading the ID Max is not a generic sub.
Seems like a lot of R&D went in to it.
If I remember correctly, when it came out, people were comparing it to the likes of W7, Mass, Crystal CMP2, Velodyne.. Not your average generic subs.

Memory might be off though.

DIYMA


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## Neil (Dec 9, 2005)

Like any driver, the impact of inductance is dependent on the intended bandwidth of the application (since this is what inductance primarily affects). Of course, the lower the inductance, the more applications the driver will work in.

Equally important is inductance linearity. Le(x), which is variation in inductance with coil position, tends to generate harmonic distortion with frequencies greater than 1.5x fs and less than 4x fs. It also generates intermodulation distortion for two tones where f1 is less than fs and f2 is greater than 7x fs.

Le(i), which is current-varying inductance, generates harmonic distortion for signals greater than 2x fs, and IMD for any two tones greater than 0.5x fs.

BL linearity and Cms linearity are both more important, in my opinion, as they generate more distortion than inductance non-linearities do. Still, it is not a reach in any stretch of the imagination to say that any driver that attempts to decrease inductance and improve the linearity of the inductance is, at the very least, a driver intended for better performance than a driver that doesn't attempt these things.

I would love to comment on the inductance of the IDMax, but alas...these things are not published. I can only speculate why...it's a 2.5" coil, obviously longer than average to achieve the stroke it does in an overhung package, and uses no shorting rings.....


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## DS-21 (Apr 16, 2005)

thehatedguy said:


> Shorting rings in subs really have little effect on the speaker's performance from the couple things that I have read...effect in the area the sub is being used at.


Mostly according to people who sell insufficiently-designed subwoofers! 



DIYMA said:


> If I remember correctly, when it came out, people were comparing it to the likes of W7, Mass, Crystal CMP2, Velodyne.. Not your average generic subs.


If by "people" you mean car audio mags, car-fi shop owners, and "competitors," that doesn't mean much. I've not seen any measurements of the driver by third parties or even from ID directly to suggest that it's anything but a rather unremarkable, generic driver.


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## Neil (Dec 9, 2005)

My earlier post mentioned that the IDMax had decent BL linearity. Guess that's what I get for relying on my memory....

http://www.sendspace.com/file/us44kg

A Klippel test would certainly be useful, though.


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## Neil (Dec 9, 2005)

Now let's compare that with the Mass...


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## Skierman (Mar 3, 2008)

Anyone have specs for the 10inch Mass?


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## ANT (Oct 15, 2005)

I think the Mass only came in a 12 inch version.The Evo came in a 10 inch. I still have one in my garage..


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## dawgdan (Aug 10, 2006)

Wrong. I am a former owner of a MASS 10". Worst decision I've made in the audio world was to sell it.

On the other hand, I am currently still in touch with the owner. He said he'll sell it back.. but it just won't fit in my install.


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## Skierman (Mar 3, 2008)

I've owned 2 10 SVC's since new. Ordered them back in May of 2002


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## Robdoggz (Sep 16, 2007)

I used to own 2 10" mass were dam nice i owned 2 12's also they were/are still decent subs but owning a pair of idmax 12's also i would take the max over the mass. For me the added spl and efficiency was worth it i gained a good amount of loudness and retained sq. 

Here are pics of my former subs unfortunately my mass 10's were stolen back in the days in 2002  Dam i miss all those subs almost as much as i miss the jl10w7's those were one of my favorites 

http://www.cardomain.com/ride/141302/2
http://www.cardomain.com/ride/141302/3
http://memimage.cardomain.com/member_images/9/web/141000-141999/141302_28_full.jpg
http://memimage.cardomain.com/member_images/9/web/141000-141999/141302_34_full.jpg
http://www.cardomain.com/ride/141302/9
http://www.cardomain.com/ride/141302/10


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## Eric Stevens (Dec 29, 2007)

Neil said:


> The MASS was an underhung driver that used a full sleeve on the pole (or a shorting ring below the gap...can't remember anymore) to further reduce, and improve the linearity of, the MASS's inductance. It really was (and still is) a great driver with better engineering behind it than even some of the popular drivers mentioned in this thread....
> 
> There is a reason the MASS is still talked about despite Audiomobile drivers being non-existent for many years now.


The Mass M2012 and M 2010 were a TC Sounds design driver designed by Steven Mowry who has posted on here several time in recent months. It is what Steven has coined the term perfectly hung. It has an extended top plate increasing the thickness close to the voice coil ID. The winding height was longer than the gap height which means it was NOT an underhung driver.

http://www.s-m-audio.com/steve_mowry.html Go here for more on Steven Mowry.

Eric

Image Dynamics


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## Skierman (Mar 3, 2008)

Robdoggz said:


> I used to own 2 10" mass were dam nice i owned 2 12's also they were/are still decent subs but owning a pair of idmax 12's also i would take the max over the mass. For me the added spl and efficiency was worth it i gained a good amount of loudness and retained sq.
> 
> Here are pics of my former subs unfortunately my mass 10's were stolen back in the days in 2002  Dam i miss all those subs almost as much as i miss the jl10w7's those were one of my favorites


In your opinion between 1 MASS and 1 IDMAX running their recommended RMS, in close to ideal sealed enclosures, which sub woofer would you prefer and why?


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## Robdoggz (Sep 16, 2007)

Sealed with the rated rms power i would have to go with the max because it would have been louder and still sound good. The mass were great imo i like think of the idmax as a mass with some extra bump to it. See i like my music pretty bassy the mass had enough spl for most people but it was limited with excursion and imo at rated power it suffered some powercompression. I am not a very technical person but this is from my experience with the two. So i would choose the max purely for the ability to get louder and its efficiency is better something like 3db more.

Also if going ported the winner imo is the max handsdown it was much more under control vs the mass ported.


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## Eric Stevens (Dec 29, 2007)

DS-21 said:


> If by "people" you mean car audio mags, car-fi shop owners, and "competitors," that doesn't mean much. I've not seen any measurements of the driver by third parties or even from ID directly to suggest that it's anything but a rather unremarkable, generic driver.


Don't know your background or how long you have had car audio as a hobby but here is some information for you. The Review by Tom Nouisane that stated "The Image Dynamics iDMAX 12 D4 subwoofer is the new king of the 12-inch hill. It has the most output of any 12 I’ve tested to date, and its response smoothness is better than or equivalent to any other 12 I know. It combines tasteful design, engineering excellence, incredible power, and fantastic sonics. If you must have the best 12-inch sub I’ve ever tested, then this is it. The iDMAX12 has only two limitations: Its mounting depth and its $449 suggested retail price." also measured the IDMAX12 for large signal parameters by DLC Design using their DUMAX method. And FYI the IDMAX12 review was done well after the review for the Audiomobile MASS 2012.

Your comments and their nature say a lot BTW 

Eric
Image Dynamics


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## bassfromspace (Jun 28, 2016)

dawgdan said:


> Wrong. I am a former owner of a MASS 10". Worst decision I've made in the audio world was to sell it.
> 
> On the other hand, I am currently still in touch with the owner. He said he'll sell it back.. but it just won't fit in my install.


Dude,

Buy it back and marvel at it.


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## DS-21 (Apr 16, 2005)

Eric Stevens said:


> Don't know your background or how long you have had car audio as a hobby


Well, I was measuring your drivers in ~1998 with the help of Dr. Wm. Marshall Leach, and finding them wildly out of spec (and graciously replaced by you because of that), so I'm not exactly new at this thing.



Eric Stevens said:


> but here is some information for you. The Review by Tom Nouisane


Dated when? 

Besides, we all know that TN is more than a little bit prone to exaggerated rhetoric. Never mind that, in his capacity as a reviewer for car-fi products he was never going to be sent most of the really good stuff out there. Do you think your industry would ever allow one of its mouthpieces to review anything like my new home subwoofer driver?

And though I probably stopped reading car-fi magazines in 1995 or thereabouts because I realized I'd learned all that they were willing to teach me by then, I presume you have a long-running ad buy in Car Stereo Review...



Eric Stevens said:


> also measured the IDMAX12 for large signal parameters by DLC Design using their DUMAX method. And FYI the IDMAX12 review was done well after the review for the Audiomobile MASS 2012.


I assume the results were basically the same as the rather mediocre results Neil posted here, supra. Otherwise, if you wished to actually make an argument instead of just posting overheated rhetoric you would've posted that data...



Eric Stevens said:


> Your comments and their nature say a lot BTW


I'll take that as a compliment, regardless of the smarminess with which it was intended.


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## cvjoint (Mar 10, 2006)

Neil said:


> Like any driver, the impact of inductance is dependent on the intended bandwidth of the application (since this is what inductance primarily affects). Of course, the lower the inductance, the more applications the driver will work in.
> 
> Equally important is inductance linearity. Le(x), which is variation in inductance with coil position, tends to generate harmonic distortion with frequencies greater than 1.5x fs and less than 4x fs. It also generates intermodulation distortion for two tones where f1 is less than fs and f2 is greater than 7x fs.
> 
> ...


Superb post! Always a pleasure to read your comments. 



DS-21 said:


> Do you think your industry would ever allow one of its mouthpieces to review anything like my new home subwoofer driver?


I'm very curious of these new drivers, especially the 15 if you have any experience with them. I turned away from xbl drivers due to excessive motor noise on the RExxx. PM me if you think it's too far off topic.


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## annoyingrob (Aug 24, 2007)

So why doesn't someone just measure the specs, and post them up here so we can stop all of this bickering.


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## 60ndown (Feb 8, 2007)

DS-21 said:


> I'll take that as a compliment, regardless of the smarminess with which it was intended.


i wouldn't.it was accurate.


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## 60ndown (Feb 8, 2007)

annoyingrob said:


> So why doesn't someone just measure the specs, and post them up here so we can stop all of this bickering.


imo, subs (boners) come and go, the max and the w7 are still here after a long time.

both great subs.

people can talk smak and paramiters all they want, but when year after year car audio enthusiasts keep using the max and w7, it means they satisfy, great sound and great output and nothing not to like.

some people just like to complain,

ignore them


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## dftnz7 (Mar 2, 2008)

DS-21 said:


> Do you think your industry would ever allow one of its mouthpieces to review anything like my new home subwoofer driver?


Your mouthpiece--an obnoxious, petulant, patronizing persona on a car audio forum--is enough to keep pretty much anyone from ever reviewing, browsing at, or really giving a **** about _your new home subwoofer driver._ You obviously have a lot of knowledge. Just a little (lot?) short in the people skills department.


Moreover, a set of specs don't always tell the whole story. When I buy a car, I don't read a set of specs, then decide what to get--I sit in them and drive them. Same with loudspeakers--the greatest set of specs in the world doesn't mean anything if it sounds like crap.


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## Et Cetera (Jul 28, 2006)

Here we go again, comparing an almost mythical sub with one of the most recognized subs in the world. I have heard so called underhung overhung shorting ring blah blah technology subs that couldn't hold a candle to an iDMax. Am I an iD fan? Yes. Now make a better sounding subwoofer (not better measuring) and make me your fan.


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## ItalynStylion (May 3, 2008)

annoyingrob said:


> So why doesn't someone just measure the specs, and post them up here so we can stop all of this bickering.


Someone drive to my house and we can test my MAX.


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## Skierman (Mar 3, 2008)

Does anyone know the specs for the 10inch MASS?


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## Vestax (Aug 16, 2005)

Might as well make a dedicated Audiomobile thread. Anybody want to throw in the EVO-R and EVO debate in here?


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## cvjoint (Mar 10, 2006)

dftnz7 said:


> Your mouthpiece--an obnoxious, petulant, patronizing persona on a car audio forum--is enough to keep pretty much anyone from ever reviewing, browsing at, or really giving a **** about _your new home subwoofer driver._ You obviously have a lot of knowledge. Just a little (lot?) short in the people skills department.
> 
> 
> Moreover, a set of specs don't always tell the whole story. When I buy a car, I don't read a set of specs, then decide what to get--I sit in them and drive them. Same with loudspeakers--the greatest set of specs in the world doesn't mean anything if it sounds like crap.


I don't think there is anything wrong with DS-21 statements. In fact they are some of the most informative posts I read every day. Sure he comes as a bit aggressive sometimes, but can you blame him? So many folks nowadays rely on voodoo from buying to reviewing that it makes their contributions nothing short of misleading verbiage. I know a good grip of loudmouths who couldn't back up the smallest irritant statement. I don't see why he needs to shield little babies, the internet is the new Colosseum and we have our gladiators. Would you prefer they'd switch to grooming each other?

I'm sure when you go out and buy an economy car you start at the Astron Martin dealer just as much as an F1 driver test drives the Prius for his daily driver. There are various signals you use to narrow down your search, just as there are in our hobby. A smart man would make use of them wouldn't you agree?


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## DS-21 (Apr 16, 2005)

annoyingrob said:


> So why doesn't someone just measure the specs, and post them up here so we can stop all of this bickering.


I believe the DUMAX report Neil posted was commissioned from DLC labs by Dan Wiggins. Eric Stevens did not challenge those data, which painted a decidedly unspectacular picture of the IDMAX, so one has to assume that they are representative of his product.

So there's no bickering about measurements. It's more like bickering between people intelligent enough to interpret measurements and head-in-the-sand types.



60ndown said:


> people can talk smak and paramiters all they want, but when year after year car audio enthusiasts keep using the max and w7, it means they satisfy, great sound and great output and nothing not to like.


Your conclusion does not follow from your premises. A more thoughtful analysis of your premises might be that "car audio enthusiasts" generally are unaware of superior options that often cost much less, because they are not typically available from the channels that offer the inferior wares of the car-fi industry. (When better products are offered from car-fi sources, they are often 3x the price of the same thing through its normal channels. See e.g. the old USD "12proB" - aka NHT 1259 - and the current Xetec and Genesis rebadges of the Peerless XLS line.) And what do you expect, considering that most shops I've visited don't even own (or have anyone who knows how to use) a box modeling program, let alone proper measurement gear.



dftnz7 said:


> Your mouthpiece--an obnoxious, petulant, patronizing persona on a car audio forum--is enough to keep pretty much anyone from ever reviewing, browsing at, or really giving a **** about _your new home subwoofer driver._


There's no difference between "home" and "car" drivers, except in the sales-pitch of someone trying to sell the more expensive and inferior one. A good subwoofer driver is a good subwoofer driver. Ten years ago, smart people were taking "car" drivers home (e.g. Jello W6, even IDQ; for a while as an undergrad I used two IDQ12's in a ported box as a subwoofer), as the only really decent "home" drivers available were the NHT 1259 and the ACI DV-series. (Even today, some car-marketed drivers are as good as the best home-marketed drivers, though the only one meeting that standard I know of is the JBL WGTi line.) Now the situation is exactly opposite. "Home" drivers have in general leapt way above "car" drivers, so today smart people are putting the better "home" targeted drivers into cars and largely ignoring the car-fi industry except where they absolutely have to (amps, etc). The best part is, those "home" drivers tend to be both a lot cheaper (even at current exchange rates, a Peerless XLS12 is ~$200, compared to apparently $450 or more for a generic IDMAX) and a helluva less gaudy. You don't have to deal with obnoxious logos or anything like that.



dftnz7 said:


> Moreover, a set of specs don't always tell the whole story. When I buy a car, I don't read a set of specs, then decide what to get--I sit in them and drive them. Same with loudspeakers--the greatest set of specs in the world doesn't mean anything if it sounds like crap.


Of course, we know a whole lot more about how to characterize a speaker (especially one with as limited a role as a subwoofer) than a car. Given the right measurements and some basic human thought, it's not hard to separate the wheat from the chaff in subwoofers. 



Et Cetera said:


> Here we go again, comparing an almost mythical sub with one of the most recognized subs in the world.


Amongst a small subset of car-fi nuts, perhaps. In the wider world, not so much. I don't see firms such as Genelec beating down ID's door for OEM contracts. (Maybe that's because their subs already use better woofers, the Peerless XLS line....)



Et Cetera said:


> Yes. Now make a better sounding subwoofer (not better measuring) and make me your fan.


I've heard the IDMAX, too, and it sounded to me exactly like what the measurements show: a generic driver. That is to say, it was no better sounding than other well-designed but generic (and much, much cheaper) drivers such as the Dayton DVC. Good enough for most people, I suppose, but hardly special. And for the price they see fit to charge for them, I expect world-beating rather than generic.

So there are literally dozens of better sounding and measuring drivers. Starting with the Peerless XLS and Dayton Reference line. (In car-fi land, perhaps the JBL W12GTi is a good place to start.) And most of them cost considerably less, to boot. Up to its excursion limits, the ~$80 Peerless SLS12 is, frankly, a better-sounding driver.



cvjoint said:


> I'm very curious of these new drivers, especially the 15 if you have any experience with them. I turned away from xbl drivers due to excessive motor noise on the RExxx. PM me if you think it's too far off topic.


I think Wiggins, et al. have learned a whole lot since the Tumult/XXX. I've not played with the Tempest-X at all, but my Maelstrom-X - mine finally came in yesterday - Kevin held it for me because I was out of town the weekend after they arrived at diycable - and during some LF sine waves playing with it out of the box it was whisper-quiet. Willy D's postings on avsforum.com say that his performed likewise. And, I might add, it's fully $100 less than the IDMAX, with almost triple the volume displacement (~2.7L vs.~7.8L) and a fully up-to-date motor with multiple gaps for enhanced BL linearity over excursion and enough Faraday shielding to bring the Le/Re ratio down to about 0.25mH/Ω. So bringing it up seems appropriate.


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## Eric Stevens (Dec 29, 2007)

DS-21 said:


> Well, I was measuring your drivers in ~1998 with the help of Dr. Wm. Marshall Leach, and finding them wildly out of spec (and graciously replaced by you because of that), so I'm not exactly new at this thing.


I have had some interesting discussions with Dr Bruce Edgar and others about Dr Leach and his work on horns. Dr Leach has some great insight on things. 



DS-21 said:


> Dated when?
> 
> I assume the results were basically the same as the rather mediocre results Neil posted here, supra. Otherwise, if you wished to actually make an argument instead of just posting overheated rhetoric you would've posted that data...


I avoid being argumentative or posting rhetoric, doesnt accomplish anything or help others in any way. I do however like to quench overheated, mis-informed and misleading posts.

In Feb 2002 Issue is when. 

The BL vs X had much better symmetry than the report attached in this thread as did the suspension compliance. I have many reports on the IDMAX and they all vary, some more than others mostly due to the DUMAX and its sensitivity to proper operation. Only common thing between all of the DUMAX reports is the magnetic center is off 4 to 5 mm. Using Klippel the magnetic center is within 2 mm which I attribute to the problems inherent with DUMAX Using air pressure to displace the diaphragm.

FYI DUMAX can achieve accurate results comparable to Klippel but the DUMAX is even more sensitive to proper understanding, operation, and setup than the Klippel. I learned this the hard way after sending some drivers in for evaluation and the resulting parameters being way off, David Clark explained the testing process to me and the possibility for inaccuracies because of the way the tests are done. David re-tested the speakers and the results were much more correct.

In fact with DUMAX it is very easy to get a ringer report that can be used for marketing purposes if you know what I mean  




DS-21 said:


> Besides, we all know that TN is more than a little bit prone to exaggerated rhetoric.


Even though his results were full of exaggeration he always calls it like he hears it. They are a business and need to sell magazines.



DS-21 said:


> I presume you have a long-running ad buy in Car Stereo Review...


We spent no $$$ with them after March 1998  The review of the IDMAX was 4 years after our last advertisement, a small 1/3 page ad, so I dont think we influenced the report with our deep pockets 


I don't withhold the inductance of the IDMAX to protect us from criticism or to prevent undue influence in any way. It just isn't a parameter that is pertinent to a driver being used as subwoofer especially when 99.5% of our consumers and dealers will never understand its meaning. Beside that it is a reactive frequency dependent parameter best described as is done in LEAP which is my preferred modeling tool. 

BTW good luck with your Subwoofer business!! If you would like to discuss things relative to subwoofer design and most specifically motor topologies, I have built and tested a lot of different stuff for us and OEM customers. 

Eric
Image Dynamics


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## Neil (Dec 9, 2005)

Well, the focus of the DUMAX and Klippel machines, while similar, is slightly different...and obviously the methodology is completely different. Still, there is some relevance in the results DUMAX provides. Even if we attribute a problem to something with a particular driver, it could possibly signal a consistency problem. Not saying one exists, though.

Does anyone have coil and gap geometry handy for the MASS? I have never in my entire life read or discussed it being anything other than an underhung driver. Maybe I should send Steve an email..... If I was misinformed, you have my apologies.


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## GlasSman (Nov 14, 2006)

DIYMA said:


> Generic?
> From my understnading the ID Max is not a generic sub.
> Seems like a lot of R&D went in to it.
> If I remember correctly, when it came out, people were comparing it to the likes of W7, Mass, Crystal CMP2, Velodyne.. Not your average generic subs.
> ...


Nope.....your memory is perfectly fine.


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## DS-21 (Apr 16, 2005)

Eric Stevens said:


> I have had some interesting discussions with Dr Bruce Edgar and others about Dr Leach and his work on horns.


Dr. Edgar used to be in the same building as you guys, didn't he? His speakers are more interesting than most home speakers, to be sure, but still sound blatantly like horns to me. As opposed to some of the better large coaxes (Tannoy, B&C, and Radian are the ones I've heard) and the GedLee Summa OS waveguides.



Eric Stevens said:


> In Feb 2002 Issue is when.


Well, that's an awfully long time ago. I'm sure TN has offered similar praise to a bunch of subs since then.
(Also, isn't that about the time he did his I-B sub? I seem to recall him using underhung TC Sounds drivers for that project....)



Eric Stevens said:


> The BL vs X had much better symmetry than the report attached in this thread as did the suspension compliance.


Of course, an alternate explanation is that your drivers vary quite a lot more than those from firms such as Peerless. I know quite well that at one point at least they did. Maybe this particular one was simply way off spec. 



Eric Stevens said:


> David re-tested the speakers and the results were much more correct.


Well, that's interesting and all, but the way to counteract data is with data, not assertions.



Eric Stevens said:


> In fact with DUMAX it is very easy to get a ringer report that can be used for marketing purposes if you know what I mean


I vaguely remember some scandal with Automobile and DUMAX numbers, but wasn't following it too closely because I was abroad on a Fulbright at the time...



Eric Stevens said:


> I don't withhold the inductance of the IDMAX to protect us from criticism or to prevent undue influence in any way. It just isn't a parameter that is pertinent to a driver being used as subwoofer especially when 99.5% of our consumers and dealers will never understand its meaning. Beside that it is a reactive frequency dependent parameter best described as is done in LEAP which is my preferred modeling tool.


What is it with car-fi companies, that you all seem to think your customers are uneducated rabble? (Well, in fairness, perhaps they are. People who understand a thing or two about these things are getting superior performance at equal or lower cost by going to Madisound, AEspeakers/Lambda, Parts Express, and some of the niche direct venders who have heavy hitters like Wiggins or Stompler in the background, so you guys really just get those who are left.) But first Zapco seems to think that it's perfectly reasonable for a customer who pays huge money for a commodity part to have to beg to be able to use it and then has the gall to claim here that their policy is anything but idiotic, and now you justify not providing information by saying that *99.5% of your customers and dealers are too stupid to understand what inductance means anyway.* Simply amazing! And you wonder why there are places like DIYMA whose entire raison d'être is to get the hell away from you people as much as possible! 

(And your point about it not being pertinent to subwoofers, is, of course, simply wrong on fact.) 



Eric Stevens said:


> BTW good luck with your Subwoofer business!!


I don't pretend to be a transducer engineer, of course. Or an engineer of any sort. Or any interest in starting any sort of audio business. My academic and practical talents are better suited to pursuits such as global poverty alleviation. I'm just an educated music lover, that's all. And there's no need to create my own company to build products I want, because by and large the market is doing a great job today of putting out subwoofers with impressive performance at reasonable prices. Not the car-fi market, whose products are by and large a teeming mass of overpriced and gaudy mediocrity (with rare exceptions such as the JBL WGTi line, which isn't exactly elegant looking but cannot be described as mediocre in performance), but the audio hobbyist market.



Neil said:


> Does anyone have coil and gap geometry handy for the MASS?


No, but I have numbers from the old TC drivers sold by Audio-X-Stream, which were basically the Crystal ones with plain dustcaps, and I assume the platform from which the Mass was developed. The vc height is 12.3mm and the gap height is 34.3mm. (That goes for the 10, 12, and 15.) Clearly an underhung driver.


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## Eric Stevens (Dec 29, 2007)

Eric Stevens said:


> Your comments and their nature say a lot BTW
> 
> Eric
> Image Dynamics


>>>>


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## bassfromspace (Jun 28, 2016)

I've yet to understand the ruckus that people kick up about subwoofers. Outside of displacement, what else really matters about them?


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## 89grand (Nov 23, 2006)

bassfromspace said:


> I've yet to understand the ruckus that people kick up about subwoofers. Outside of displacement, what else really matters about them?



I don't get it either. As far as I'm concerned, the main difference between some subs is power handling, and the ability to withstand abuse. Other than that, nothing really too important. I refuse to buy expensive subs...because I'm sure I couldn't tell the difference.

I couldn't pick out a Mass from an IDMAX just by listening to them if I was paid to.


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## Neil (Dec 9, 2005)

Just like every other driver, the lowest distortion possible is preferable if "accuracy to the source" is the goal. And certainly not every driver will sound the same, although this obviously relies on the listener.

Waiting for a reply on the motor geometry from a reliable source.


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## bassfromspace (Jun 28, 2016)

Neil said:


> Just like every other driver, the lowest distortion possible is preferable if "accuracy to the source" is the goal. And certainly not every driver will sound the same, although this obviously relies on the listener.


From my understanding, our ability to discern differences in the low frequencies is quite a bit lower than higher frequencies. I also understand that the "best" subs typically operate above 20% thd.

With that said, are the differences between subs noticeable enough to raise a fuss over or are we gonna argue specs?


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## DS-21 (Apr 16, 2005)

bassfromspace said:


> I've yet to understand the ruckus that people kick up about subwoofers. Outside of displacement, what else really matters about them?


You make a very good point in your first sentence. Subwoofers are talked about (by everyone, myself certainly included) way more than their importance justifies. The cynic in me thinks that it's just because it takes much less thought and work to get a big boom then to attain smooth, coherent response through the midrange. The other 5% of me thinks the cynic is right. 

Then again, people also make a ruckus about things that, once they reach a basic (and fairly cheaply attainable) level of competence, matter not at all from a sonic perspective, such as digital sources, amps, and wires. At least subwoofers can and do sound different from one another!

When I started out I thought displacement was basically everything, too. Then I started hearing some (even by modern standards) very high displacement drivers* that made something less than music, and started looking into why. Later on, I learned that those drivers had very high inductance, and no Faraday shielding to linearize it over excursion. I started looking at drivers I had subjectively found to be excellent and those I didn't, and a pattern quickly emerged: those with less inductance and Faraday rings always seemed to be at the top of the heap, and those without them sounded inferior.

People way smarter than I am seem to feel the same way. Dr. Earl Geddes recently posted the following on diyaudio.com as part of what's probably the most interesting conversation on the internet for audio geeks right now:
"You are missing the single biggest reason that I use the 12TBX100, it has a shorting ring. This I consider critical in a "competent" design because quite honestly I can't see why anyone would make a speaker without it."

As for what matters aside from volume displacement, I would say suspension linearity, heat management, shorting rings, motor linearity, low inductance, low inductance variation. That said, the driver that's still my overall favorite, JBL's W15GTi, seems to have decent-but-not-exceptional BL and linearity (to be sure, way better than the posted measurements of the IDMAX) per Klippel measurements here. It does have extremely low inductance, and probably more rigorously engineered thermal management than any other driver out there. I haven't had a chance to do any critical listening with my Maelstrom-X, so that opinion has a possibility of changing.



89grand said:


> I don't get it either. As far as I'm concerned, the main difference between some subs is power handling, and the ability to withstand abuse.


Funny, those two things are of almost no import to me. If a sub's power-handling is low, that's almost a blessing because you can buy a smaller, cheaper amp that uses less energy. (Of course, for deep bass that means a bigger box, because that's what determines efficiency down low.) And if you can get the same SPL with lower power, then you'll probably also get better sound because less power means less heat to dissipate and accordingly one would hope less thermal compression. I've never blown a driver that wasn't one of those stupid little Jordan JX53's in my life, so I suppose I'm either easy on equipment or have a predilection for having excess capability so that everything's loafing along. 



89grand said:


> I couldn't pick out a Mass from an IDMAX just by listening to them if I was paid to.


I wouldn't be so sure. Not to say that the differences would matter to you particularly much, or that you might not prefer the inferior driver to the more accurate one, but the differences aren't so subtle as to require millenia of Talmudic parsing.

*The drivers in question were from TC Sounds, using their overhung 3HP motor. For everything that's been said of TC Sounds here, they've also produced more than their fair share of stinkers, and have had serious QC problems pop up rather more often than would make one comfortable. Their underhung drivers that I've heard have never been less than superb, though. Ditto their TC2+/TC1k overhung designs. And though I've not heard one, credible third-party measurements of their TC2k suggest it was a standout performer, too.


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## thehatedguy (May 4, 2007)

Dr. Geddes is also operating that 12 up to about 1k hertz too.


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## thehatedguy (May 4, 2007)

So, he's XOed at about 900 hertz. I would think the difference in having the need to be able to play that high vs. playing 80 hertz would influence speaker design differences.

But I could be wrong.


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## chijioke penny (Mar 22, 2007)

ItalynStylion said:


> Someone drive to my house and we can test my MAX.


I have (7) of them in my tahoe  if you want to test


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## dftnz7 (Mar 2, 2008)

DS-21 said:


> My academic and practical talents are better suited to pursuits such as global poverty alleviation.


Alas, a noble, worthy, wistful, youthfully optimistic, and fundamentally unattainable ambition. Just make us some speakers for crying out loud. If you are half as good at designing/building them as you are at criticizing the efforts of others, your subsequent revenues could then be used to help alleviate global poverty!


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## DS-21 (Apr 16, 2005)

THG, if you read Dr. Geddes' comments on that thread (and elsewhere over the past several years) he doesn't limit his insistence that Faraday shielding is a necessary condition for a competent driver to units playing up to ~1kHz. Interestingly, in the thread I quoted, supra, Dr. Geddes doesn't focus too much on the raw inductance value. He writes that he prefers a higher number because he uses the driver's Le in his crossover design. I think it's certainly possible to distinguish that comment so that they square with my observations, in that he's not exactly contemplating drivers with the horrific levels of inductance with which many long-throw subwoofer drivers are blighted, but more reasonable numbers. The "higher inductance" B&C 10PS26 used in the GedLee Summa, for instance, has and Le/Re ratio of ~0.21mH/Ω, or a similar number to good-sounding subs such as the JBL W1xGTi and Exodus Maelstrom X. Worlds away from a nasty TC 3HP or (one must assume, given their reluctance to provide the data) an IDMAX.



dftnz7 said:


> Alas, a noble, worthy, wistful, youthfully optimistic, and fundamentally unattainable ambition.


I don't believe it is unattainable at all. Yes, there will always be _relative_ poverty. No two ways around that. And I'm somewhat glad, too, because the wait time for my most recent made-to-order commission from Edward Green is already way too damn long. I don't want another 100k people in the queue!

But people without access to basic things such as clean water, shelter, sanitation, electricity, nourishment, health care, literacy, and communications... I think we not only can we do something about that but it is a moral imperative for those of us with skills that can help and the wherewithal to be able to still live comfortably without selling our souls to Big Law/a hedge fund/one of the big global consultancies to do something. 

So, for someone like me I think it best that audio remain a hobby that at best pays in drips and drabs through "criticizing the efforts of others." Think of someone like Dr. Edward Said, who had a standout academic career but also wrote music criticism for The New Republic. For some living examples, consider Dr. Fred Kaplan or Dr. Anthony Cordesman; both do serious national security work but review music and audio gear on the side.


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## Skierman (Mar 3, 2008)

Still,, looking for specs so I can determine what airspace this driver needs for a sealed enclosure?


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