# TB speakers 8x12?



## cvjoint (Mar 10, 2006)

I've been toying around with ideas for the S2000. Since I'm restricted to 9 inch height in the spare tire well I am only looking at 8 inch woofers. 

Now this thing is 8 on one side so it fits the criteria, it is also 12 inches wide which makes for a lot of surface area, as much as an 11 inch sub. 

Parts-Express.com:Tang Band W8Q-1071F 8"x12" Subwoofer | W8Q-1071F subwoofer 8"x12" subwoofer long throw subwoofer tangband tb speakers










Ideally I'd want to hear from someone that has used it before, but the support is very limited. Are TB speakers decent? Does this one have a shorting ring, seeing how the LE is lower than 1 @4 ohms? Lastly, what are some other options?

I've been looking at the Jl 8W7 too, and the RLi. None of the other options seem to get much output. The TB 8X12 will have more output than any of the above and at least they publish an LE spec :surprised:


----------



## ItalynStylion (May 3, 2008)

I've not tried these but they definitely have intrigued me before. I just never really had the need.


----------



## bassfromspace (Jun 28, 2016)

I'd put money on the w7 over that TB.


----------



## cvjoint (Mar 10, 2006)

The size is just a perfect fit. I just want to make sure it doesn't have obvious downsides like motor noise or it falls apart. 

As for the Jlw7 I don't think there is much to doubt. these have twice the surface area of a 8w7. Even with the limited xmax 12mm vs. 19mm it should put out more output. Maybe the Jl has considerably more mechanical throw but I'm not interested in that, linear is what I'm going for.


----------



## Candisa (Sep 15, 2007)

I have a pair of TangBand W4-1337SA fullrange speakers and they sound fantastic. I recently gave a "demo" of them in our living room, playing free air, no box, not even a baffle. 
The person that was listening to them said they sound fantastic and you should know he has a full Dynaudio Esotar² set powered by Sinfoni amps in his car (his brother owns a caraudio shop)!

Does this mean everything from this brand is good stuff? No, as a matter of fact, Xenia first ordered a set of TangBand W4-1320 fullrange speakers to use in her own install. These are basically the same speakers as the W4-1337, but with a bamboo cone instead of titanium. 
The 1320's have more of a live, ambient sound, while the 1337's have more of a studio, clean sound, which is a matter of taste, BUT... the 1320's lack a LOT of detail compared to the 1337's, so she ended up sending her 1320's back and pay the difference to get 1337's instead...

PS.: The combination of a 1320 and a 1337 playing together gives something very very beautiful and we are considering building a pair of MTMW home speakers with that combination in the future, but if you only have the space for only 1 of them per side (which is already big enough to put quasi-on-axis on top of the dashboard of a car), the 1337's are a LOT better than the 1320's and we still don't understand how 2 very similar speakers of the same brand and with so little difference in price can be so different in sound quality.

Personally, I wouldn't risk using these 8X12's unless somebody I really really trust (there are lots of superpositive reviews of that W4-1320's too...) has experience with them and even then I would ask if I could test them. 

Xenia ordered a pair of CSS Trio8's recently, but she also recommended them to one of her friends who did test them and he LOVES them and likes them better than his IDMax 12"!
Those Trio8's only need an optimum sealed enclosure of .5cu.ft.. In a car and with some stuffing, I'm sure they'll do a great job already in .33cu.ft., so if you have enough space for 2 round 8" woofers, you might consider a pair of those. If you don't have enough space for 2, you might think about using 1 and maybe port it if you don't have enough output sealed...

Those Trio8's have 14mm of x-max, which is less than the 19mm of the JL, but when such a small cone is moving that much, it WILL make unwanted noises, so I would rather have a little less output choosing a lower-but-still-high x-max driver and have great sound quality, than spending a LOT more to buy a rediculously-high x-max driver that sounds bad anyway if you use the extra excursion...

Isabelle


----------



## ItalynStylion (May 3, 2008)

Have you modeled the tang band in your available space? I'd do that before weighing the options too much. Model both the JL and the Tang Band and see which response curve looks better.

The Tang Band subs are great from my experience. I've not tried that one but I've run through 12 of the 6.5" subs and I'm hooked. I had 4 in my IS300, I build another IS300 box for a customer with 4 in it as well, and now I have 4 in my Toyota Tacoma....plus another 2 in my room that I have home audio plans for 

The Trio8 is a great driver (otherwise I wouldn't sell it on my site) but I don't know if it would be as great a candidate here if you're considering the W7. That makes me think output is a factor so I'm not sure. The benefit though is that you could likely do a Trio8 ported where as you'd only be able to likely have the W7 sealed.

How much enclosure space do you think you have?


----------



## cvjoint (Mar 10, 2006)

I guess I should have mentioned my "box" plans or lack of it thereof 

I plan to do IB again. A Qts around 7 and a low FS are desirable but not necessary for this application. To get true IB if there is such a thing I need to do 10x VAS and that's not going to happen anyway. The S2000 trunk is 5 ft3, that's going to make for a large sealed box. 

Candisa you seem to have had good track record with the TB drivers. I doubt I'll find someone with experience with these in particular. Most likely I'll have to buy one and play with it free air if nobody can chip in. Well, I was one of the first to try out the AEIB15 and those turned out to be gold, repeat performance?! haha

It's funny you mention high xmax noise because at the meet yesterday some guy was telling me the JL does get noisy at high xmax. I was a bit skeptical of the good low motor noise reviews, that basket is hella restrictive imo. 

ItalynStalion I've seen nothing but good reviews about the smaller ovals. That is all positive news. 

On to the trio 8. The shallow design is not needed in my application so that doesn't benefit me. It seems to have rather large impedance too. I do love the triple shorting rings, that is a very nice touch. The low SD puts it at a great disadvantage to the TB, and xmax is lower the 8w7. Otherwise it is a very nice pick, I'll keep this one in mind. I did look at it to begin with. Coming from two AEIB15 I will notice the loss in output. For the sub department I will need to get all the output I can.


----------



## SQ_Blaze (Sep 29, 2008)

cvjoint said:


> I've been toying around with ideas for the S2000. Since I'm restricted to 9 inch height in the spare tire well I am only looking at 8 inch woofers.


Why are you "only" looking at 8" subs or that TB 8x12?

You have plenty of options for very capable 10's and 12's that will fit in an enclosure in that space you have and easily outperform that TB. Even if you use 1" MDF, you still have 6.5" of mounting depth to work with. And that's not even including all the quality shallow mount subs out there now.

I had my SI MAG D4 V2 in an enclosure no deeper than 8" on the outside and I guarantee that sub would rip the TB a new one!


----------



## ryan s (Dec 19, 2006)

cvjoint said:


> I guess I should have mentioned my "box" plans or lack of it thereof
> 
> I plan to do IB again. A Qts around 7 and a low FS are desirable but not necessary for this application. To get true IB if there is such a thing I need to do 10x VAS and that's not going to happen anyway. The S2000 trunk is 5 ft3, that's going to make for a large sealed box.


George, 10x Vas is a truism for the home environment. 4x Vas is "car IB" or "door IB" since we have limited space. 

I'm sure if I'm wrong, someone will tell me :surprised:


----------



## ItalynStylion (May 3, 2008)

How are we going to IB a sub in an S2k? Everything in this thread has made sense up until that point lol


----------



## cvjoint (Mar 10, 2006)

IB is definitely doable. I can IB 2 of those 8x12 suckers, or any other 8. Height is the only restriction. It's going to fit where the spare tire goes. I plan to make it removable in less than 1 minute and too keep the trunk space unchanged. Just like the Accord this will take years to complete, but I now know a heck of a lot more than when I first started with that car and slapped on Polk DB speakers haha

My IB idea should kick any of those floor board mounted sub setups if these TBs pan out. If you look at the sensitivity, SD, and throw of these suckers they have lots of potential and in IB it will be high fidelity, dig deep and save me weight and trunk space. It's a no brainer. I can fit two and use 5ft3 to help them breathe, it's going to beat a 12 shallow mount sub in the floor pan. Besides, I never like to mount speakers up or down firing. 

The VAS rule of thumb is just that, a rule of thumb. I see no reason why we should change it for car audio, especially since I will get next to no cabin gain in this car.


----------



## ItalynStylion (May 3, 2008)

cvjoint said:


> The VAS rule of thumb is just that, a rule of thumb. I see no reason why we should change it for car audio, especially since I will get next to no cabin gain in this car.


I think the reason it changes (educated guess) is because you're not looking for the same response curve in a car that you want in the house. In a car you'll have significant cabin gain for the low end where as in the house the room gain will be much less. Keeping that in mind, I'd imagine that a smaller IB ratio would be acceptable in a car.


All of that aside, my question about your alignment has to do more with the S2k itself. Most IB installs are done in the rear deck or against the rear seats. In most instances your rear wave is sealed from the front wave of course but the front wave is IN the cabin. How do you do that in an S2k? Am I missing something? I thought there was no type of pass through from the trunk where the spare is to the main cabin. I need an S2k education. :S


----------



## cvjoint (Mar 10, 2006)

ItalynStylion said:


> I think the reason it changes (educated guess) is because you're not looking for the same response curve in a car that you want in the house. In a car you'll have significant cabin gain for the low end where as in the house the room gain will be much less. Keeping that in mind, I'd imagine that a smaller IB ratio would be acceptable in a car.
> 
> 
> All of that aside, my question about your alignment has to do more with the S2k itself. Most IB installs are done in the rear deck or against the rear seats. In most instances your rear wave is sealed from the front wave of course but the front wave is IN the cabin. How do you do that in an S2k? Am I missing something? I thought there was no type of pass through from the trunk where the spare is to the main cabin. I need an S2k education. :S


I see what you are saying about the VAS in a car, but I don't think the S2k will have much of a cabin gain. On the other hand I don't think it will suffer from reflections. My rule of thumb is to never get a speaker's Q above the ideal. Lower than .7 is not really a problem.

Well the S2k is a better IB car than my Accord. I'm super excited of working on this car. Unlike most behind the seat IB setups this one will actually have about a 2 x 3 ft breathing hole behind the seats. IB looks like cake, no restrictions and it's a lot easier to seal off. 

You can even do IB in a hatch, you just have to get creative.


----------



## 60ndown (Feb 8, 2007)

JL Audio TW5 Subwoofers - Car Audio Subwoofers

put em in your headliner


----------



## rkgantz (Apr 14, 2010)

Any one have any of the Tang Band 8x12 for sale? I've been looking all over and they appear to be soldout.


----------



## Patrick Bateman (Sep 11, 2006)

cvjoint said:


> I've been toying around with ideas for the S2000. Since I'm restricted to 9 inch height in the spare tire well I am only looking at 8 inch woofers.
> 
> Now this thing is 8 on one side so it fits the criteria, it is also 12 inches wide which makes for a lot of surface area, as much as an 11 inch sub.
> 
> ...


If I'm not mistaken, this is basically the 8" Tang Band woofer, but with a different cone and basket. The motor is identical IIRC.

I've built a gazillion boxes with it's MCM equivalent, and it's a killer woofer (for the price.)

Having said that, I'm really getting to the point where I can't listen to a woofer if it doesn't have shorting rings, and underhung motor, or both. The price difference is almost nil nowadays, and they sound a hell of a lot better. If you've seen my Triple8 thread, it uses the woofer that I'm speaking of. I've pitted that box against a sealed box with the Diyma12, and a tapped horn with an underhung neodymium woofer from P-Audio. Basically the MCM gives you the most output for the money, but the other two sound and measure better. (IE, lower distortion.)

Low distortion is particularly important at low frequencies, because of the Fletcher Munson curves.

Last but not least, a painless way to reduce distortion is to use push-pull mounting. It's free and it works.


----------



## ItalynStylion (May 3, 2008)

The Tang Band 8" is a neo magnet design no? Or is there another one that you're referring to?


----------



## cvjoint (Mar 10, 2006)

Patrick Bateman said:


> If I'm not mistaken, this is basically the 8" Tang Band woofer, but with a different cone and basket. The motor is identical IIRC.
> 
> I've built a gazillion boxes with it's MCM equivalent, and it's a killer woofer (for the price.)
> 
> ...


Good read. I see you used a version of the TB 8 that did in fact had the same motor. Are you saying this one does not have shorting rings? I can't really tell, the LE seems to be low enough that it is possible. What was your favorite 8? I see u used the CSS one as well. 

IB is the method of choice for me. I need them to extend high and low, 20hz-120hz and do so weighing as little as possible. I'm hoping the output will be decent due to the large SD. I have no restrictions for power/coil configuration. The restrictions are low weight and one dimension being 9 inches max. 

I can mount three of these ovals IB or 4 8 inch subs. The three ovals will have 1/3 more SD than any 4 8s.


----------



## Patrick Bateman (Sep 11, 2006)

ItalynStylion said:


> The Tang Band 8" is a neo magnet design no? Or is there another one that you're referring to?


If I'm not mistaken, their 8x12 is the basically a W8-740P with a different basket and a different cone.

Parts-Express.com:Tang Band W8-740P 8" Subwoofer | subwoofer 8" subwoofer long throw subwoofer tangband tb speakers tangband-41108

It basically offers a ton of excursion for not a lot of money.

The MCM 55-2421 is kind of a cut-rate version of the same driver. Somewhat crummier build quality, and less excursion. I paid about $25 each for mine IIRC. I bought ten and one of them was DOA. Then again, I've seen TB woofers that were DOA too, so YMMV.

The Creative Sound eight is in a whole 'nother ballpark. But the CSS requires a relatively large box for an eight, due to the high QTS.


----------



## Patrick Bateman (Sep 11, 2006)

cvjoint said:


> I've been toying around with ideas for the S2000. Since I'm restricted to 9 inch height in the spare tire well I am only looking at 8 inch woofers.
> 
> Now this thing is 8 on one side so it fits the criteria, it is also 12 inches wide which makes for a lot of surface area, as much as an 11 inch sub.
> 
> ...


Is the back wave channeled to the outside of the car? If that's the case, you could stack three or four eights like a stack of pancakes. If you can squeeze four into the tirewell, that will give you more output than a pair of twelves. (Assuming xmax is equal.)

It will look like a Tymphany LAT:
















The CSS Trio8 is under four inches deep....


----------



## cvjoint (Mar 10, 2006)

I took this pic awhile ago:









That's where the donut goes. I was going to mount two 8 inch subs facing the camera so to say. Note that that I can remove that lid from above and have it breathe in the cabin easy. That is also only half the trunk. In the left side there is a gas tank so depth becomes important if I want to go with the third oval or 3,4th 8. 

The trunk itself is 5 cubes so that should be enough for 4 CSS trio8 if need be. The cone side of the sub will breathe in the 5 cubes. The motor will vent in the cabin up through the removed lid. 

4 CSS trio8s would work in parallel off an Arc Mini 500.1 getting about 500w at the 2 ohms. 

3 TB 8x12 would be fed 750w from 1.5 Arc minis 125.4 (6 channels bridged, 2 per sub)

The TB setup will obviously own in output. The question is how good would it sound? It seems like the CSS is nicer with the triple shorting rings, and a more advanced motor structure. I might give up some surface area for that. So far it seems like the CSS is preferred by some of you. The TB might nonetheless have shorting rings.


----------



## T3mpest (Dec 25, 2005)

IMO a system that has more output capabilities in this case will also probably have lower distortion. Both drivers have a low enough inductance that when you cross them over at 80hz like not going to get much inductance variation over it's stroke. The biggest difference is that when the other drivers are all the way at xmax, the tb's will be able to reach that output level at only 3/4 excursion. There is no replacement for displacement, lots of cheap woofers often sound very good when used in large groups as with lower excursion levels they do just fine. Plus, the more cone area you have the less you'll miss the switch from the 15. The question becomes, is the Trio that much better that even when it has to move 
50% further to reach the same output level, will it still sound better. IMO, subbass SQ is mostly about LFE, level matching, phase, ie how it integrates to your midbasses. All of those qualites except for LFE is pretty much install and tuning related, LFE is a product of cone area in your case.


----------



## Patrick Bateman (Sep 11, 2006)

cvjoint said:


> I took this pic awhile ago:
> 
> 
> 
> ...


XBL motors are kinda infamous for having low sensitivity. But the truth is that their motor force is actually spread out over the entire xmax range. For instance, a sub with a conventional motor will see it's motor force diminish as the excursion increases.

In other words, the sensitivity of the driver isn't consistent across the whole curve. If you've ever poured gobs of power into a sub, and it doesn't want to get any louder, you've heard this phenomenon. This is also one of the reasons that conventional subs sound a lot boomier when you're dumping a ton of power into them. Due to the reduction in motor force, the Q of the enclosure actually changes at high excursion.

Long story short: Why use a conventional motor? I have a pile of Audax and MCM subs I can't even listen to any more.


----------



## SSSnake (Mar 8, 2007)

> Why use a conventional motor?


Because if the conventionally motored sub is undergoing less excursion there *could* be (depends on the speaker) less variation in Bl, inductance, etc. than a non-conventionally motored sub (translation - sometimes a big ol' chevy V8 puts out more power than a Porsche turbo charged 4). 

Additionally, *ALL *subs will


> see it's motor force diminish as the excursion increases.


While Xbl subs help linearize Bl through their stroke they do suffer from more rapid fall off beyond Xmax. Some have argued that this extreme non-linearity once excursion gets beyond Xmax is detrimental to SQ (However, I am not very concerned with this area of operation). It is all a tradeoff and depedent upon the intended use of the drivers.

IMO - TB for the win.


----------



## ItalynStylion (May 3, 2008)

The trio 8's aren't in stock right now. I sold the last pair of them about two weeks ago. I'll have to ask Bob when we're getting more.

So at the moment we know two things for certain; the TB has more cone area but the Trio8 has a lower distortion motor. Have you modeled either of these in the configuration that you plan on using? I'd model them first to check response and then make the call after seeing response curves.


----------



## Patrick Bateman (Sep 11, 2006)

SSSnake said:


> Because if the conventionally motored sub is undergoing less excursion there *could* be (depends on the speaker) less variation in Bl, inductance, etc. than a non-conventionally motored sub (translation - sometimes a big ol' chevy V8 puts out more power than a Porsche turbo charged 4).
> 
> Additionally, *ALL *subs will
> 
> ...


One of these days I need to find a few hours and find out how effective push-pull is at low frequencies. I measured it in the midbass, and it lowered 2nd harmonic by close to 10dB at certain frequencies. So that's a *huge* difference.

It would be great to find out if that's effective down to 40 or 20hz. Due to the small size of the woofers I was testing with, they were basically unusable below 100hz.









Tom Danley, who built the most powerful sub in the world, uses a push-pull configuration of TangBand W8s* in one of his subs. Based on some stuff I read on the bass list, Tom considered an XBL motor for one of his subs, but found that push-pull was more effective.

I've never seen any published data though, vis a vis XBL vs push-pull.

* While this woofer appears identical to the one you're discussing, I believe Tom has his custom built. Tom probably tweaks the design to increase power handling and to get a specific set of parameters for horn-loading. But the basket and magnet appear identical to the one you can buy from PE.


----------



## T3mpest (Dec 25, 2005)

SSSnake said:


> Because if the conventionally motored sub is undergoing less excursion there *could* be (depends on the speaker) less variation in Bl, inductance, etc. than a non-conventionally motored sub (translation - sometimes a big ol' chevy V8 puts out more power than a Porsche turbo charged 4).
> 
> Additionally, *ALL *subs will
> 
> ...


Lol having the Bl fall off past xmax is a good thing. It's a built in limiter. With XBL^2 you can basically get the xmax up to near the suspension limits. The older brahmas has 28-30mm of xmax and would hit suspension limits before 40mm, IIRC 36mm was about the limit on that suspension. The sharp BL drop stops you from easily bottoming the woofer out on accident and helps keep it within it's linear range, IMPROVING SQ if anything. You need very little power in most cases to reach it's clean excursion limits and then above that point, you need more power than you'll likely have on tap to overdrive it. It's like having a car with a limiter that limits the gas input once you begin to redline or begin to travel way too fast.

Doesn't push pull distortion only deal with even harmonics? Those are usually considered somewhat pleasant to listen to and not nearly as obtrusive. I'd be more conerned with the odd order ones and a push pull won't help those AFAIK. I'd bet the XBL^2 motor, if it didn't have lower overall distortion probably did have lower odd order, so even if the total distortion was objectively higher, it was probably subjectively better souding due to the lower distortion that human ears actually tend to notice. That's all a supposition on my part however.


----------



## cvjoint (Mar 10, 2006)

All sorts of good information going on here. I'm not sure towards which one I lean on at the moment but there is obviously lots to think about. 

I would think a pertinent question is could I notice a difference in the two drivers at similar output while the Trio8 is in its linear range. It's pretty obvious that past a certain SPL level the TB drivers will sound nicer since they will be well within their linear range while the CSS will not. If TB can hold its own throughout the SPL range then it will be a clear winner. 

I'm thinking of matching them with a pair of B&C drivers up front in the doors:
B&C SPEAKERS
I'm going to guess that if I restrict them to 120hz up these might be able to belt out 110db full range at the given 140w. 

From what I understand the demodulating ring has lots of properties that might not be readable from the LE spec alone. Given the abundance of aluminum used in the CSS it might do particularly well say 80hz - 120hz. The TB is also oval, and I doubt that cone is variable thickness to make up for it. A free air comparison would be nice.

I'm not too worried on the response as long as I can give them enough air to breathe. I can EQ. out low end bass easily. 

I'm not sure I follow on the push pull thing. It's a cabinet design is it not? Why would you compare it with XBL, a motor topology? From that pic that box is a no go, any box really. In IB all I need is a 5 lb baffle to make them sing. That box would surely take over all my trunk space if it would even fit and weigh around 20lbs.


----------



## Patrick Bateman (Sep 11, 2006)

T3mpest said:


> Doesn't push pull distortion only deal with even harmonics? Those are usually considered somewhat pleasant to listen to and not nearly as obtrusive. I'd be more conerned with the odd order ones and a push pull won't help those AFAIK. I'd bet the XBL^2 motor, if it didn't have lower overall distortion probably did have lower odd order, so even if the total distortion was objectively higher, it was probably subjectively better souding due to the lower distortion that human ears actually tend to notice. That's all a supposition on my part however.


Maybe I've been measuring too many drivers, but I find distortion really noticeable now. I'll admit that some of it doesn't sound "offensive", but I notice it. Particularly when the subs are generating it, because it tends to "pollute" the midrange. At this point I'd rather have no subs than have subs that screw up my midrange.


----------



## SSSnake (Mar 8, 2007)

> Lol having the Bl fall off past xmax is a good thing. It's a built in limiter.


You are missing the point. If operated in this range you effectively clip the crap out of your waveform. Agreed it is right before reaching maximum excursion but it was suggested that a gradual roll off in BL is less audible. This was from a post on DIY Audio. It struck me as odd as well. However the poster, who I will not identify because I can't find the link, was VERY knowledgable and well qualified to provide this opinion. 

Back on topic the B&C 6s are awesome in the range you indicated. I wouldn't hesitate to use them. They use an aluminum shorting ring rather than the copper cap used in the 8NDLs but are still VERY capable speakers.

Push pull does help and I would recommend it for subs. Unless I am mistaken it does only affect the even order distortion but it is still well worth the effort.


----------



## T3mpest (Dec 25, 2005)

SSSnake said:


> You are missing the point. If operated in this range you effectively clip the crap out of your waveform. Agreed it is right before reaching maximum excursion but it was suggested that a gradual roll off in BL is less audible. This was from a post on DIY Audio. It struck me as odd as well. However the poster, who I will not identify because I can't find the link, was VERY knowledgable and well qualified to provide this opinion.
> 
> Back on topic the B&C 6s are awesome in the range you indicated. I wouldn't hesitate to use them. They use an aluminum shorting ring rather than the copper cap used in the 8NDLs but are still VERY capable speakers.
> 
> Push pull does help and I would recommend it for subs. Unless I am mistaken it does only affect the even order distortion but it is still well worth the effort.


If a standard design goes well past xmax it's going to be distorting heavily anyway, beyond xmax almost always ove 10% distortion. 30mm of xmax which most XBL^2 designs can give you is alot. Your also getting most of that XMAX very easily. Non XBL^2 drivers BL falls off well before you reach xmax, go look at a curve. Half way to xmax the Bl starts to slowly drop and every time it does, your power consumption needed to get more excursion increases. So does the overall Q of the woofer which greatly impacts your frequency response. You end up with a sub that begins to thermally compress in output well before xmax, less low end as the Q is quickly rising, and all of this is happening well within it's useable limits. With XBL^2 the sub has a Q that doens't change, so frequency response WITHIN it's useable limits is basically static, same sound, just louder. Also you get less power compression within useable limits as the BL isn't dropping so it's holding it's effeciency. 

I guess what it come down to is that I'd rather have a driver be more effecient and linear within it's limits and not be able to exceed that than a driver that will lose effeciency and a linear response at the "gain" of being able to overdrive itself for a quick dynamic peak.

I can see where he's coming from, but if you really plan on pushing a driver past XMAX, you didn't pick the right number of drivers, or the correct driver to begin with. So saying that it's dynamically limited beacuse it won't drive itself 5mm past it's actual intended range easily is a bit of a fallacy, IMO. A standard driver, is dynamically limited in the same way, it just happens more gradually,but it also happens within the intended usage limits, that makes it worse, IMO. I'd rather have a driver that will operate at low levels just as it does at high levels.

An XBL^2 driver doesn't truly sound strange due to this design in terms of dynamics. What happens is as you turn your gains up, you simply find at a certain point the driver doesn't sound any different. It doesn't get louder, or begin to distort, or do anything nasty. It simply takes more and more power sounding perfectly fine until the coil begins to smoke lol. Once you find that point where it stops getting louder, you back off. The only issue is that due to the lack of  BL drop, it hits that point pretty early in terms of power. It gets steadily louder and then, boom, nothing else. To some people I suppose this is unnatural as they are used to increasing Q and distortion as the volume increases. The lack of change is what sounds unnatural to those used to a standard motor. 

Edit: to get back on topic. IMO, no if both drivers are used within their intended limits you won't hear any remarkable differences in their bass. IMO, the biggest difference will be that the TB's will get alot louder overall. I like low inductance and XBL^2 designs alot my three subs were a Brahma, Avalanche, and a AV15, but that's an awful lot of cone area to give up. All things equal the flattened BL curve makes XBL^2 a superior option, but this really isn't a fair fight. The TB's use a good motor, not a great one like the Trio, but still a good one. IMO, it's akin to putting a 120lb world class featherweight up against a 250lb national level fighter. Techinically, the 120lb'er has it's advantages, but that's simply too much size to make up for when the bigger guy is "good enough".


----------



## thehatedguy (May 4, 2007)

I dunno. Talking about distortion in subwoofers operating as a subwoofer, like below 60 hertz is like seeing who can clap the loudest with one hand. You won't hear it.


----------



## thehatedguy (May 4, 2007)

Dr. Geddes has said he would rather have a sub that had a gradual falling off in BL rather than one who was flat and suddenly dropped off.




SSSnake said:


> You are missing the point. If operated in this range you effectively clip the crap out of your waveform. Agreed it is right before reaching maximum excursion but it was suggested that a gradual roll off in BL is less audible. This was from a post on DIY Audio. It struck me as odd as well. However the poster, who I will not identify because I can't find the link, was VERY knowledgable and well qualified to provide this opinion.


----------



## T3mpest (Dec 25, 2005)

thehatedguy said:


> I dunno. Talking about distortion in subwoofers operating as a subwoofer, like below 60 hertz is like seeing who can clap the loudest with one hand. You won't hear it.


I agree with this wholeheatedly, which is why I was against the whole push pull thing, especially if it's only affecting even order. IMO, the biggest advantage in XBL^2 is the lack of parameter shift, which I did like. I'd like to see his argument, but if it hinges on being able to run into your suspension limits 12mm past xmax for the sake of "dynamics", then I'd be inclined to disagree with him, regardless of his PhD's lol.


----------



## Patrick Bateman (Sep 11, 2006)

thehatedguy said:


> I dunno. Talking about distortion in subwoofers operating as a subwoofer, like below 60 hertz is like seeing who can clap the loudest with one hand. You won't hear it.









Wat?!

Let's say you're running a sub with an 80hz lowpass that's 12db/octave. If second harmonic distortion is 18db below the fundamental, that means that over 50% of the sub's output at 160hz will be distortion!

Even someone with tin ears can tell when 50% of the output is distortion 

The graph above compares the distortion of a Dyanudio, a Dayton, and a Scan Speak woofer. These are excellent drivers, and you can see that distortion performance like that is pretty typical.

(As you know, there's no way to electronically reduce distortion. Even if you have a 96dB/octave crossover, it won't do a thing about distortion.)


----------



## T3mpest (Dec 25, 2005)

Patrick Bateman said:


> Wat?!
> 
> Let's say you're running a sub with an 80hz lowpass that's 12db/octave. If second harmonic distortion is 18db below the fundamental, that means that over 50% of the sub's output at 160hz will be distortion!
> 
> ...



yeah, but in a trunk car your going to have a pretty big acoustic dip by 160hz anyway due to the seats and whatnot. 12db electrical will usually be much higher at the headrest position, compared to the mids playing right next to you I doubt you'll hear a major difference. Especially if you haven't fully deadened very panel in the entire car as the amount of distortion they will add to your signal at any appreciable volume level is probably more than the sub itself. There is a point of diminishing returns in a car. Even geddes only uses the B&C de250's on his waveguides as they are "good enough" because the room is the ultimate limiter. Thats playing in a band where distortion and whatnot is very audible and with a very advanced waveguide to minimize room interactions in the first place. If we step that down to the subbass region in a car, what kind of performance levels do we really need? Here's the response of a woofer that can easily play up to 2k placed into a trunk car. Notice the 40 decibel dip at 80hz that is almost purely acoustic filtering? That's somehwhat typical in a vehicle. With altered placement he got the red curve but that's still 20db's down. I think he used a 80hz crossover point, so realstically 3dbs of that was electrical.


----------



## thehatedguy (May 4, 2007)

I just read Geddes's Audio Transducers, and it really opened my eyes and reaffirmed somethings that I had strong feelings on.

The major cause of distortion in speakers is from BL fluctuations. Almost any subwoofer made in recent times will not have that much fluctuations in flux to really make a hill of a difference when we are talking about subwoofers being used as subwoofers. Can it be measured? Sure. Is it fun to engineer and push technology past previous limits? Sure. But can we hear it in our environment considering how insensitive our ears are in that area? Yeah...I'm not too sure about that. 

And if we are concerned with flux modulation vs. excursion...use a pair of larger subs to keep excursion low at listening levels. Or use some sort of enclosure that maximizes output vs. excursion. All we are doing with subwoofers in the car is creating pressure changes.

Now the argument of low distortion speakers gains weight as you move up in frequency.


----------



## T3mpest (Dec 25, 2005)

thehatedguy said:


> I just read Geddes's Audio Transducers, and it really opened my eyes and reaffirmed somethings that I had strong feelings on.
> 
> The major cause of distortion in speakers is from BL fluctuations. Almost any subwoofer made in recent times will not have that much fluctuations in flux to really make a hill of a difference when we are talking about subwoofers being used as subwoofers. Can it be measured? Sure. Is it fun to engineer and push technology past previous limits? Sure. But can we hear it in our environment considering how insensitive our ears are in that area? Yeah...I'm not too sure about that.
> 
> ...


To me the distortion isn't the issue. A decrease in BL will cause a increase in distortion, not a huge issue. However, the frequency response of the driver is impacted as well as the Q of the driver rises as BL drops off. You can easily tell me distortion doesn't matter with a sub and I'll agree, frequency response, not so much. Having a sub goes from q of .5 up to a .7 as you increase power to it is an actual issue, IMO. Also, no one can easily argue power compression isn't an issue and if it has to occur anywhere, I'd much rather have it occur outside the drivers intended excursion limits, vs inside.

Anyway if Geddes reasoning wasn't correct, people wouldn't talk about how low inductance and constant Bl drivers tend to sound different than older standard designs. A XBL^2 driver does have a unique sound vs regular designs. The biggest thing thing I notice is the lack of parameter shift, the driver simply never gives any sign of distress unless your right next to the cone. If the sub is in a trunk it simply sounds the same at low or high volumes, it just gets louder. With most subs as you begin to push them they start to sound boomy as the Q rises, low end drops off some and you know your pushing too hard.

Do you have a link to the paper/book your talking about, I wouldn't mind reading it. Also for anyone who hasn't seen it


----------



## cvjoint (Mar 10, 2006)

The subs will be ~ 2feet away from my head. The only thing between us will be speaker cloth :anxious:

From my previous install it seems that absorption is not necessarily that acute:
Here is my previous setup with 3 IdMax 12s in IB, Accord leather seats, mic at the driver's head. 








One of them is seats up, one down, then the trunk is open for both another. They seem very usable up to 100hz where the filter kicks in. In fact I tested subs up to 200hz in this arrangement and the absorption seemed to kick in strongly at about 150hz. In the case of the S2000 there won't be almost anything to absorb high frequencies in the way and I will run them possibly up to 120hz.


----------



## SSSnake (Mar 8, 2007)

I hate that I missed out on the rest of this conversation.



> Dr. Geddes has said he would rather have a sub that had a gradual falling off in BL rather than one who was flat and suddenly dropped off.


Thanks for that Jason. After looking over at DIY and not finding the quote I was beginning to believe that I had imagined the whole thing :blush:

I guess I need to break down and buy a copy of Geddes's Audio Transducers.

Tempest,

I too look for drivers that have minimal fluctuation of parameters under load. However, it is difficult if not impossible to know which designs will or will not possess this trait. XBL has the potential to be a very good motor topology but so does underhung. You can even see overhung designs that are better than XBL. My point is a good implementation of a simple motor design is likely to outperform a poor implementation of a complex motor design. This is why I staunchly believe this statement is the right approach.



> And if we are concerned with flux modulation vs. excursion...use a pair of larger subs to keep excursion low at listening levels. Or use some sort of enclosure that maximizes output vs. excursion.


Now this assumes you have the space to install more drivers. If not having a larger Xmax helps but with the potential for more parameter variation. That is why I suggested the TBs.

FYI
I still own XBL drivers (Avalanche 18s). I like the design overall but IMO the inductance is much too high in the Avas. I believe in letting the subs work higher than most (around 75hz is my preference to be moved up or down based upon the midbasses I am utilizing). The Avas just really didn't do this well. I'm not sure why but it seemed to be inductance related (again this is just my opinion).


I have heard the Brahmas and many times liked what I heard. I am very interested in the Maelstrom, Shiva X, and Tempest X designs. I am using the AE IB 15s so I do believe in using drivers with good motors.


----------



## cvjoint (Mar 10, 2006)

I entered both drivers in WinIsd, surprisingly they model exactly the same. I used 140L sealed as the volume of the trunk and split it in 4 if the CSS was modeled or 3 if the TB was modeled (that's how many I can fit). Q comes in at .53 and .54, easily withing parameter variation.










If AE made an 8 inch sub I would probably get it, the AEIB15 was my favorite of all that I have used.


----------



## thehatedguy (May 4, 2007)

Be forewarned, Geddes does not make the math in the book "horsey and ducky." I have had undergrad Differential Equations and Linear Algebra, and I wasn't following a lot of the math that well. It wasn't one of those books you just sit down read it and go build some crap because you just read it. To make the most of the book and the maths involved, I think you would want to have a good back ground in a program like Matlab- or something like it (I'm not an engineer so we didn't get to use any software other than Maple).

However the chapter on distortion was worth the read.

Books


----------



## SSSnake (Mar 8, 2007)

I am an EE so I can probably keep up (though it will likely take some effort  )


----------



## Patrick Bateman (Sep 11, 2006)

thehatedguy said:


> Be forewarned, Geddes does not make the math in the book "horsey and ducky." I have had undergrad Differential Equations and Linear Algebra, and I wasn't following a lot of the math that well. It wasn't one of those books you just sit down read it and go build some crap because you just read it. To make the most of the book and the maths involved, I think you would want to have a good back ground in a program like Matlab- or something like it (I'm not an engineer so we didn't get to use any software other than Maple).
> 
> However the chapter on distortion was worth the read.
> 
> Books


I picked up Audio Transducers at the RMAF. Did my best to slog through it, despite all the math. At the time I was building a lot of waveguides, so I really wanted to come up with a proper spreadsheet for designing one. (This is a year before I built my first set of Unity horns.)

For the life of me, I couldn't find the equation in the book!

The next day I asked Geddes where it was. And he said it's not in there! So he scrawled the formula on a napkin and I still have it sandwiched inside my copy of the book 

That's what I used to publish my spreadsheet, which ended up on a thread over on htguide.com.

While he's received a lot of kudos for Audio Transducers, I personally prefer his articles in the JAES and his home theater book. They're a lot more accessible to someone that's math-deficient like me. (I'm a software engineer, not an EE.)


----------



## thehatedguy (May 4, 2007)

I'll have to get the other book too and find those JAES articles too. I really respect the man and what he has to say. The more I learn, the more I respect him.


----------



## thehatedguy (May 4, 2007)

I asked Jeff to read it an 'plain it in Engrish 



SSSnake said:


> I am an EE so I can probably keep up (though it will likely take some effort  )


----------



## T3mpest (Dec 25, 2005)

SSSnake said:


> I hate that I missed out on the rest of this conversation.
> 
> 
> 
> ...


Technically XBL^2 should lower inductance as you can use a shorter coil and still get longer xmax values. I do agree with you on the avalanche though, no matter what you do you can't get good output out of it above 60hz. It probably is inductance or inductance vs excursion related.

What standard overhung designs do you consider better than the best designs of XBL^2 or LMS? As dan points out in his XBL^2 primer, there are very few downsides to XBL^2 as long as the overall design is good. You lose some BL due to the shorter coil, but you potentially gain BL at the end of it's stroke where a standard design drops off. Given a set of T/S parameters a driver that properly uses XBL^2 will probably be better overall than a underhung or overhung design, especially if it uses faraday rings in conjunction. There are simply less downsides overall to the design. Sure it's not required in every case, but all other things equal, I'd say it's a safer bet to assume it's an improvement. 
www.acousticdev.com/Files/XBLPrimer.pdf


----------



## 60ndown (Feb 8, 2007)

T3mpest said:


> A XBL^2 driver does have a unique sound vs regular designs. The biggest thing thing I notice is the lack of parameter shift, the driver simply never gives any sign of distress unless your right next to the cone. If the sub is in a trunk it simply sounds the same at low or high volumes, it just gets louder. With most subs as you begin to push them they start to sound boomy as the Q rises, low end drops off some and you know your pushing too hard.


nice explanation.tech talk is pointless unless we can translate it into every day talk.


----------



## T3mpest (Dec 25, 2005)

cajunner said:


> I've read that the build has to be perfect to extract the type of gains XBL2 has over the standard overhung designs, that being off just a little with wind height will mess it up a lot. If this is the case, what about drivers that develop a millimeter or two of sag? I've seen this on so many drivers, they get a little out of alignment but still play decent, I am wondering if this holds true for XBL as well, or is it not a factor?
> 
> sag will take that voice coil out of alignment, and I read that the difference of a single winding will knock XBL down a notch on distortion profiles, is this true?
> 
> ...



Well your always going to lose some BL in an underhung design. Your not taking advantage of the fringe field so your xmax will be a bit lower too. Dan did spend a while talking about driver sag. He even had a tech paper that gave you a formula to know if a driver was safe to mount vertically. I'm not sure if this was due to XBL^2 and gap alignment, or just because he felt it was important in general.


----------



## cvjoint (Mar 10, 2006)

The part about suspension tightening at the end of the linear travel doesn't sound so good to me. If you listen to something very dynamic you would have to set the volume very low so the rare musical peaks don't push the speaker too far. That would make xmax less usable imo.


----------



## T3mpest (Dec 25, 2005)

cvjoint said:


> The part about suspension tightening at the end of the linear travel doesn't sound so good to me. If you listen to something very dynamic you would have to set the volume very low so the rare musical peaks don't push the speaker too far. That would make xmax less usable imo.


It's not the suspension tightening, it's the motor physically stops pushing as hard. As BL drops on ANY speaker this occurs. Lets say your regular speaker has 30mm of xmax and a standard non optimized by curve. It's 70%bl at 30mm, but realistically, it's losing BL from every point from 15mm onward. If your regular contest asks for 10m of excursion and then you get a burst of wattage that should cause, lets say a 6db db burst. That is a doubling of input power and should take 20mm of excursion. On a non-bl optimized speaker, you wont' get that 20mm. Bl has already started to drop slightly so the compression will have already kicked in. Now you have 17mm instead on that peak. Because of this, your already losing output at regular listening levels. 

On a xbl^2 motor, with 30mm xmax, this compression effect happens very quickly at the very edge of it's linear travel. In the above case, a XBL^2 motor or any BL optimized motor will reproduce it perfectly. For example, the TC sounds LMS ultra has a 1%bl deviation at 32mm IIRC. If your using anything less than 32mm of throw, it will give you exactly the excursion you should be seeing. So in the case of the 10-20mm jump, it'll have no issues and respond as it should.

The question becomes, do you want the speaker to constantly be losing bl at the range you'll be listening to it most of the time, or only lose BL at the very end of it's linear travel? loss of bl is loss of bl, the further you can push a driver before it begins to lose it the better. Just think, if you had a driver that has 32mm of xmax and was keeping 99.9% of it's BL up to 31, would you say it's a crappy design since that last mm is incredibly compressed? A linear BL motor we have today like xbl^2 is similar to that, just not quite that extreme. The brama has about 32mm of linear travel due the suspesion on the rearward stroke. 27mm of it was within the 30% BL deviation we consider xmax. The first 20mm or so you'd lose no BL at all for all intents and purposes. If you use enough drivers to never need more than 20mm, you'd get a 100% perfect signal as far as BL was concerned, a non optimized driver, due to the bl dropping so fast would match that point at 10-15mm if you were lucky.

I guess the thing to realize is BL compression happens on all speakers all the time. The closer to the suspension or useable BL limits (xmax) you can push the drop off the better.

Also, that's the last nice thing about this design. On a regular speaker you get a gradual BL drop. Even beyond xmax it doesn't drop like a rock or anything. If you hit a dynamic peak and you've already given it enough power to get near xmax, and taken all the BL loss you incur in doing so, lets's say you hit another big peak. Now you WILL have to worry about it bottoming out, since xmax is still dropping, but even though your past where you should be operating the speaker, it's still going to try.

So overall the non optimized speaker is really losing out. It's easier to overdrive mechanically and less effecient over 99% of it's travel. Sure, beyond xmax it may have less BL deviation, but that's not really a good thing. It makes it easier to break and isn't useable output anyway, at least not clean distortion free output. Also at normal listening volumes (lets face it in a car with 20db's of gain a sub is usually moving less than 25mm on music) your suffering less BL compression. You only suffer compression right at the end, where techically both speakers are beginning to "fall apart" SQ wise. The only difference is the XBL motor will maintain composure for much longer and wont' allow itself to be overdriven to destruction. Plus, they can use nice soft spiders and let the motor do the job of keeping the sub in check.

With an XBL^2 design. Xmax drops hard just before xmax and drops quickly after it too. If you hit xmax, even on hard peak, you won't be able to move the cone far enough to mechanically damage it. Once you get past your clean output level (xmax), the BL drops off and the motor loss will mechanically protect it. Unless the peak was dynamic enough to smoke the coil, it won't break. Plus, since you don't incur much BL compression BEFORE xmax, that' probably not the case.

Here's pics that help illustrate. The top driver is the adire extremis, bottom is the AA poly mid. Same driver basically minus a few changes here and there, biggest being xbl^2. At 7.5mm the extremis drops off pretty sharply give you 9mm xmax. At 6mm, on the extremis, which is alot of excursion for a 6' mid, more than many have period, you have basically no BL loss. All the nasty effects of BL loss are a non issue. Then go look at the AA poly mid. Xmax at 8mm, so pretty close to the same 30% point. But at 
6mm, shoot it's BEEN sloping down for a LONG time. To keep it as linear as the extremis mid, you'd have to use what, the 2.5mm mark each way??? 

edit: the dip in the XBL^2 is a artifact, IIRC. So the upward curve you see isn't even there, if it is it's less pronounced than it appear, and it's not very bad at all anyway, very shallow slope... .6 n/a over 
7mm, the other driver can barely make .6n/a over a 3.5mm range.



Uploaded with ImageShack.us










In summation you can complain that yeah, the BL curve drops pretty quickly at 24mm on a 30mm driver using XBL^2. Remeber this though, the first 24mm you have no losses occuring at all, it's basically perfect in terms of BL related distortion, Q jumping around, etc. Ask yourself, is that really worse than a driver that starts messing things up at 7mm and slowly continues to do so until it also reaches the 30mm mark at 70% BL? How often will you use that last 6mm, especially in a car... How often will you use the first 24 that the XBL motor can use without any issues?


----------



## cvjoint (Mar 10, 2006)

Excellent post. I guess what we're talking about here is a shortage of BL/xmax measuring standards. It sounds like the torque/horsepower debate in the car audio realm. Seeing the torque curve is all you need just like how you need to see the BL curve to draw proper inference.

I'm sold on the XBL2 having a superior BL curve. Now what does it means exactly to have a dropping BL? Can I rectify it by giving the speaker more power? I think you guys mentioned earlier how the Q might change but I'm not sure. 

It seems like if needing more power is the only downside then you may want same motor topology on both subs and woofers, otherwise the XBL2 drivers will be louder and louder up to 70% BL.


----------



## T3mpest (Dec 25, 2005)

cvjoint said:


> Excellent post. I guess what we're talking about here is a shortage of BL/xmax measuring standards. It sounds like the torque/horsepower debate in the car audio realm. Seeing the torque curve is all you need just like how you need to see the BL curve to draw proper inference.
> 
> I'm sold on the XBL2 having a superior BL curve. Now what does it means exactly to have a dropping BL? Can I rectify it by giving the speaker more power? I think you guys mentioned earlier how the Q might change but I'm not sure.
> 
> It seems like if needing more power is the only downside then you may want same motor topology on both subs and woofers, otherwise the XBL2 drivers will be louder and louder up to 70% BL.



Well the more BL you have the more effecient the speaker is. BL is measured in N/A as you can see in the graphs. newtons of force/amphere of current. As the BL drops, the electrical Q of the woofer goes up, as I mentioned your getting less xmax than you should and excursion down low is decreasing. The quicker Bl losses set in, the less effecient the speaker will be. That's why alot of XBL^2 woofers are actually very effecient especially at low frequenies where excursion is required. Their 1db/1w/1m wont' indicate it necessarily, but they are. Down low that's a useless spec anyway. Basically though, your losing BL because the coil is leaving the magnetic gap. This makes the speaker less effecient so you need more power to make up difference. So on paper while a non BL optimized speaker may look more effecient due a higher BL or higher effeciency rating, it rarely is in practice. Once the driver begins to move, the Q goes up, low bass gets cut off and the BL drops. As I said earlier in this thread, the nice thinga bout XBL^2 drivers is they actually find their limits pretty easily. You turn it up till it stops getting louder, then stop. It'll get louder and louder very quickly and easily within xmax limits. Once you get near xmax, it'll stop getting louder, even as you throw ALOT of power on it. Back up at that point. 

Like a real world example. I had my AA avalanche hooked up with a bass knob below my dash. With about 600 watts of input I could pretty much get 99% of the output out of it as far as I could tell from the cabin. When I turned the gains up any higher i didn't hear any more bass, before that point, it went up very quickly and linearly with my volume knob. If I turned it up any more, I had to turn it up ALOT before anything changed and at that point it was making mechanical noises.

I guess the overall point is, XBL^2 speaker tend to be more effecient than they appear since most drivers lose BL as they move and that means losing effeciency. That can be a downside I suppose. You get them to level match at low levels, but if your mids arent' optimized and they are moving alot, yeah, they will begin to suffer BL compression and give out at higher volumes where as your subs stay clean. That's not really the subs fault tho lol. I usually don't run my midbasses very low tho so I don't have much first hand experience with that problem. I use high effeciency mids crossed sorta high usually so nothing compresses much.


----------



## cvjoint (Mar 10, 2006)

And when the Q goes up I imagine it's the same thing as your box getting smaller? Does the FR change?

So I'm guessing the CSS SDX7 mid would actually have a rather low sensitivity. Nonetheless it would be a good match to the Trio8. Two possible choices:

3x TB 8x12 + B&C 6 (18sound 6 ok too, but they don't seem to use a shorting ring and this is a mid)
-the filter would be around 120hz
or

4 x CSS Trio8 + CSS SDX7 
-the filter can be lower here, 100hz


----------



## T3mpest (Dec 25, 2005)

cvjoint said:


> And when the Q goes up I imagine it's the same thing as your box getting smaller? Does the FR change?
> 
> So I'm guessing the CSS SDX7 mid would actually have a rather low sensitivity. Nonetheless it would be a good match to the Trio8. Two possible choices:
> 
> ...



yes, the electrical q going up is just like the box getting smaller since it raises the overall q. I'd go with the first option if it was me. The B&C's are more effecient in an xmax limited scenario for sure. The cone area of the TB drivers certainly can't be ignored either. In a small car you can usually cross the mids higher before they localize too, especially if you make sure you don't have any rattles back there. I've used a couple B&C drivers before and they've all been top notch.


----------



## cvjoint (Mar 10, 2006)

T3mpest said:


> yes, the electrical q going up is just like the box getting smaller since it raises the overall q. I'd go with the first option if it was me. The B&C's are more effecient in an xmax limited scenario for sure. The cone area of the TB drivers certainly can't be ignored either. In a small car you can usually cross the mids higher before they localize too, especially if you make sure you don't have any rattles back there. I've used a couple B&C drivers before and they've all been top notch.


Dr. Geddes seems to use the B&Cs I was thinking off. Can't be too bad 

I've seen people swear on PHL gear, but there is virtually no mention of this brand on DIYMA. I wonder why.


----------



## T3mpest (Dec 25, 2005)

cvjoint said:


> Dr. Geddes seems to use the B&Cs I was thinking off. Can't be too bad
> 
> I've seen people swear on PHL gear, but there is virtually no mention of this brand on DIYMA. I wonder why.


PHL is nice, but sorta expensive. I've auditioned the 1120's and the 2520's. Both were vere nice speakers, but pretty pricy even used. B&C drivers are a better value/performance for sure. B&C is well priced most of the time and it's a good bet it will sound good as well. AE has a new 6.5 coming out very soon too.


----------



## SSSnake (Mar 8, 2007)

> What standard overhung designs do you consider better than the best designs of XBL^2 or LMS?


I wasn't saying that overhung was "better than the best of XBL^2 and LMS". It is my belief that it takes more than just XBL^2 and LMS to make a good woofer. I'll go back to the Avalanche example. I have two sitting in my living room on a LFE channel rather than in my car. The reason, IMO, is poor inductance linearity (and overall high inductance). I prefer to use an underhung driver (the AE IB 15) because of it's extremely low inductance AND low distortion motor design. the combination of two technologies was successful in this case. The AVAs are supposed to have shorting rings but they don't seem to be as effective as the rings in the IB15 (this is very likely due to a shorter lower power coil but for my application I prefer the IB15).

Now a direct comparison of overhung to XBL^2 is hard for me to do because I haven't really listened to those side by side or with as much listening time. The best comparison I can give is the Brahma 10 versus the Peerless XXLS 10. The Peerless is massively overhung (33mm coil with 8 mm gap) and still sounds VERY good. Would I prefer it over the Brahma? I don't know but I do know that it would be in the running.

Several other good overhung designs are the B&C 6MD38 and 8NDL51. To me saying that a woofer is better because it is XBL versus over or underhung is just premature. There are a lot of things in a motor that make it a quality design.


----------



## cvjoint (Mar 10, 2006)

T3mpest said:


> PHL is nice, but sorta expensive. I've auditioned the 1120's and the 2520's. Both were vere nice speakers, but pretty pricy even used. B&C drivers are a better value/performance for sure. B&C is well priced most of the time and it's a good bet it will sound good as well. AE has a new 6.5 coming out very soon too.


You said *soon* haha. The AE IB15 is underhung, sob I never knew. Maybe I'll wait for the AE 6.5 and 8s to come out.


----------



## SSSnake (Mar 8, 2007)

> The AE IB15 is underhung, sob I never knew


It appears to be...

Their Lambda motor is underhung. They go on to say that the Apollo motor is the Lambda motor with extra shorting rings. They offer the Apollo motor as an option for the IB15. I may be putting two and two together and getting twenty two but...


----------



## cvjoint (Mar 10, 2006)

T3mpest said:


> PHL is nice, but sorta expensive. I've auditioned the 1120's and the 2520's. Both were vere nice speakers, but pretty pricy even used. B&C drivers are a better value/performance for sure. B&C is well priced most of the time and it's a good bet it will sound good as well. AE has a new 6.5 coming out very soon too.





SSSnake said:


> It appears to be...
> 
> Their Lambda motor is underhung. They go on to say that the Apollo motor is the Lambda motor with extra shorting rings. They offer the Apollo motor as an option for the IB15. I may be putting two and two together and getting twenty two but...


I think I finally figured out where all this discrepancy in info over the IB15 comes from. Here's a quote from John @ AE on the UB-15:
_These were built as a custom project for Dave, although we do plan to offer them as really the ultimate in infinite baffle woofers in the future. The benefit over the standard IB15 is that they have the underhung motor for nearly perfect BL linearity up to the Xmax range. This massive underhung design though does come at a price because the massive hand machined top plate is not cheap. They are also quite heavy. Modeled in bassbox you get a Qtc of .707 in 10cf, so a pair will be about perfect in most standard trunks. I'm not sure why you are seeing 47cf.

John_

I was telling people my IB15 weighed 17lbs and I got called on, had to pull out the scale. It turns out this one guy Dave had a custom IB15 built, the UB-15: heavier ~45lbs if I recall correctly and apparently underhung.


----------



## SSSnake (Mar 8, 2007)

I do have to recant my statement. After re-reading their article it appears that they were comparing the Lambda to an underhung. Wow that means I like this overhung motor better than the Ava's XBL^2. Actually that makes a better argument for my statement.

Sorry about the confusion and thanks for the follwing info 



> think I finally figured out where all this discrepancy in info over the IB15 comes from. Here's a quote from John @ AE on the UB-15:
> These were built as a custom project for Dave, although we do plan to offer them as really the ultimate in infinite baffle woofers in the future. The benefit over the standard IB15 is that they have the underhung motor for nearly perfect BL linearity up to the Xmax range.


I thought that I had heard the IB15 was underhung before... With the small top plate I guess I should have known better.


----------



## cvjoint (Mar 10, 2006)

Does anybody have BL curves for AE speakers/lambda?


----------



## cvjoint (Mar 10, 2006)

The output models fairly modest even with the TB:









107db @20hz is the max I'll get out of them with 0 cabin gain (which is likely in a roadster I imagine). The mechanical limits (within xmax) are about 104db @ 20hz. 

I hit 135db at 20hz on a meter with my 3 IDMax IB but that was with twice the power and cabin gain of a coupe. It was likely bottoming out though, but 130db @20 hz seemed realistic with that setup within xmax. 

I think I'll pass on the CSS based on output alone.


----------



## Patrick Bateman (Sep 11, 2006)

cvjoint said:


> Dr. Geddes seems to use the B&Cs I was thinking off. Can't be too bad
> 
> I've seen people swear on PHL gear, but there is virtually no mention of this brand on DIYMA. I wonder why.


I've used the B&C eight, and the CSS eight, and they're both good. But they're good for different reasons. The B&C has superior build quality, much higher efficiency, and seems capable of taking almost limitless power. The CSS is less expensive, can play a LOT lower, but also needs more power to get there.

I've often wondered if a different cone on the CSS could turn that subwoofer into a woofer. The inductance on the CSS is low enough to play to 1500hz or even 2000hz.

But that's all academic; at the moment the B&C is a superior for woofer user, and the CSS is superior for *subwoofer* use.


----------



## DS-21 (Apr 16, 2005)

Hmm...the Trio8 motor with something like the old Audax aerogel cone would be an interesting driver. Too bad mine are spoken for, otherwise that might be an option.


----------



## beerdrnkr (Apr 18, 2007)

Didn't read the whole thread but Boston Acoustics makes some oval subs that can handle a ton of power and I've read that they sound really good too.


----------



## DS-21 (Apr 16, 2005)

cajunner said:


> I mean, why doesn't somebody make an 8" neo-radial with the 12" MR or 794 series motors and have the ultimate mid bass?


IMO and assuming the same cone and surround materials (i.e. Mms going down with size), the 794-series (3" coil) Aura motor would just be too much for an 8. After all, my NS10-794-4A gets a Qtc in the 0.6's in just 12L or so. Now, if Aura would make an 8 with their 513-series (2" coil) motor (which is also a whole lot cheaper)...I'd buy 'em.



cvjoint said:


> Dr. Geddes seems to use the B&Cs I was thinking off. Can't be too bad


Did you see Dickason's latest B&C test, of their 18SW115-4? Oh my, that driver measured really, really well. "Picture perfect" BL symmetry. 
22 _Voice Coil_ 7, (May, 2010) at 13. (Measurements at 17.) AudioXpress has VC for free right now, but I don't have the link as I'm looking at an exported PDF of the issue.



cvjoint said:


> I've seen people swear on PHL gear, but there is virtually no mention of this brand on DIYMA. I wonder why.


Lots of factors: poor distribution (IIRC only Andre/espeakers.com carries them in the US), expensive, and shockingly little manufacturer-published data considering they're in the pro market. I've thought about picking up some of their drivers (especially the coaxes) a few times, but the paucity of available data gives me pause.



SSSnake said:


> I wasn't saying that overhung was "better than the best of XBL^2 and LMS". It is my belief that it takes more than just XBL^2 and LMS to make a good woofer. I'll go back to the Avalanche example. I have two sitting in my living room on a LFE channel rather than in my car. The reason, IMO, is poor inductance linearity (and overall high inductance)...The AVAs are supposed to have shorting rings but they don't seem to be as effective as the rings in the IB15 (this is very likely due to a shorter lower power coil but for my application I prefer the IB15).


Odd that you'd put the lower-fidelity driver in the more demanding environment, but whatever. I think you're right that it takes more than a general motor topology to make a good woofer, be it XBL^2, LMS, Differential Drive, or even underhung NRT! BUT, all else equal, an underhung woofer is going to be the most linear, followed by one of the trick motors (LMT, XBL^2, Differential Drive), followed by straight overhung. And either the Differential Driver or the LMT will have the best thermal performance, followed by the overhung, with either the XBL^2 or underhung bringing up the rear. (Why? Relative thermal mass.)

One factual issue though: the Avas lacked shorting rings, which is one reason they weren't as good as they could have been. (For a while I had an Ava-18 in my home theatre. I replaced it with a Maelstrom-X, which was a huge improvement. The Aura drivers with which I replaced the Maelstrom-X are probably no better, but the M-Design cabinets are much prettier...)



SSSnake said:


> Now a direct comparison of overhung to XBL^2 is hard for me to do because I haven't really listened to those side by side or with as much listening time. The best comparison I can give is the Brahma 10 versus the Peerless XXLS 10. The Peerless is massively overhung (33mm coil with 8 mm gap) and still sounds VERY good. Would I prefer it over the Brahma? I don't know but I do know that it would be in the running.


Well, that's not really fair, because the Brahma lacks shorting rings. Given that the Brahma has a suboptimal early XBL^2 implementation, and the XXLS has a super implementation of an overhung design, I'm not sure it would be as close as you think. I think the XXLS would walk away, within its excursion limits. An XLS12/XXLS 12 vs. an Exodus Shiva-X, which has XBL^2 and shorting rings, would be an interesting comparison, though.



beerdrnkr said:


> Didn't read the whole thread but Boston Acoustics makes some oval subs that can handle a ton of power and I've read that they sound really good too.


The BA oval subs aren't in the running compared what else we've discussed here. No shorting ring, not well-executed motor or suspension, and expensive. Not to mention subpar power handling. See BA SPG-555 Klippel measurements.


----------



## cvjoint (Mar 10, 2006)

beerdrnkr said:


> Didn't read the whole thread but Boston Acoustics makes some oval subs that can handle a ton of power and I've read that they sound really good too.


The TB ovals fit so that's nice, the BA ovals only come one size from what I could find and it does not fit. The fact that it handles lots of power is nice, but I'm more interested in maximum linear output and sensitivity. 

From npdang's test this subwoofer is just a mediocre driver at best, and to be honest that's about as good of a review as we'll ever get, no one has stepped up to the plate with better reports. 



DS-21 said:


> Did you see Dickason's latest B&C test, of their 18SW115-4? Oh my, that driver measured really, really well. "Picture perfect" BL symmetry.
> 22 _Voice Coil_ 7, (May, 2010) at 13. (Measurements at 17.) AudioXpress has VC for free right now, but I don't have the link as I'm looking at an exported PDF of the issue.


I remember the test for the 8 inch B&C here on Diyma and that BL curve was as flat as they come. The only such curve I've seen was on the Extremis. I went on to buy those 8s and used them as a dedicated midrange for a long time. They were really good as a midbass too but don't quite have the cojones for sub duty.


----------



## thehatedguy (May 4, 2007)

FWIW, I have bought PHL from Zalytron, which at the time (2003) was the only place to get it. They (zalytron) are running close outs on discontinued PHL, and the price might be low enough to get you to try it out.


----------



## cvjoint (Mar 10, 2006)

As far as the 6.5s go the S2000 has very limited space in the doors. I will have to take the panels off and check maximum depth available. So far it seems like these are the following depths:

AE 6.5 88mm (est.) $150 pre-order

B&C 6ndl38 85mm $130

PHL (1361 - e speakers est. based on 1220 1330) 76.5mm $175

18Sound 6nd430 73mm $130

I prefer them in these order too, with the AE being first choice. If the 18sound doesn't fit I will have to sacrifice the door panel because no other driver would give me enough output and fidelity yet have a smaller depth.


----------



## 60ndown (Feb 8, 2007)

cvjoint said:


> I'm more interested in maximum linear output and *sensitivity. *
> 
> .


power is cheap, and powerful amps are small, why risk being disappointed with performance the first time you go for a drive (and cant hear/feel any bass?) and having to do it all again

put a real sub in there with real power.


----------



## cvjoint (Mar 10, 2006)

60ndown said:


> power is cheap, and powerful amps are small, why risk being disappointed with performance the first time you go for a drive (and cant hear/feel any bass?) and having to do it all again
> 
> put a real sub in there with real power.


You forget you are in the mobile environment, how much power can you generate on the go? A 60 amp alternator only goes so far. You can upgrade to a HO alternator but then you have dismal power at idle. Your car will suffer under heavy draws, dim lights, rpm drops, alternator whines and eventually dies. Sure you can buy a good alternator but that's $400 plus if you are serious. Then you need a $180 optima of a decent size, larger cables. You are taking up more trunk space as you need larger heatsinks to keep that power going. On the sub side you get power compression. Sensitivity goes a long way in the car environment. Most setups can only sustain a small portion of the available amplifier power. 

Money aside this is an S2000. Aside from an aluminum tub, Honda designed this to be as light and ideally balanced as possible. Countless top notch engineers spent considerable time designing the car as sharp as they could, distributing a pound here and there between the front and rear axle and shaving weight whenever possible. 

It is a big deal


----------

