If you feel a smaller subwoofer is faster than a larger one - the enclosure is NOT optimized for the larger one. No manufacturer would produce a "slow" subwoofer. Even within the same series of speakers, say the W7 line from JL for example, the motor on the 8W7 is identical to the 13W7. This demonstrates that the motor is strong enough to have control for the heaviest cone - and sound good.

I've had 15"s in my car that didn't have ANY enclosure (mounted IB), and were some of the tightest subs I've ever heard!

The only time you'll be able to notice a spacial cue in acoustic music is when the speakers (subwoofers in this example) are SPACED APART, and infront of you! There's only a few competition cars that I can think of that use this setup. 99.9% of cars, where the subwoofers are mounted behind the listener, there will be NO difference in sound quality between mono and stereo subwoofers. Again, most of the time the subwoofers should be wired mono.

 

 

It's not a fair comparison. To try to use your car anology...as long as both vehicles are able to move to 0.5mph, and stop in the same distance, everything is equal. Subwoofer frequencies are not high enough for anyone to discern what is a "faster" subwoofer". IF they feel there is a difference, the enclosure for the "slower" sub is not optimized.

The "BL" is essentially the T/S parameter that is equal to motor strength. Again, ANY quality subwoofer is going to have enough motor strength to be "quick". Despite what "MMS" (mechanical moving mass) is, rest assured, it'll be light enough for the motor to move at these low frequencies. If you want to validate your point, move the frequency up - where the cone's mass will have a much greater affect. The difference in weight between a 8W7s cone, and 13W7s cone is minimal - and won't have ANY effect on sound quality - especially due to the strength of the motor.

IB = Infinite Baffle - utilizes the trunk's airspace for the enclosure.

My car:


I've got a 12" mounted up front now. Crossover points for subwoofers should be kept as low as possible - never above 80hz. The higher you have it set, the harder it will be to integrate properly with the midbass drivers, and the more musical energy/output will come from behind you. The more musical energy (re: lower crossover point) you can use with your front speakers, the better.

 

Here I am with my girlfriend Robyn taking home the World Champion trophy for sound quality at last year's USACi World Finals:

 

Yes... you are right. normally, most subwoofer lowpass are kept below 80Hz... and that is probably the reason you and I disagree on the "fast" bass theory so much. It isn't until the higher frequency bass (60Hz-150Hz) that you can really start to notice the reaction time of the subwoofer. If you have a 12" subwoofer hitting continuous .5 Second 100Hz bass notes at 1 second intervals... you will start to notice that the cone will not "bouunce back" fast enough from the first note before it goes into the second note. On a 10" subwoofer, you will be able to differentiate the notes clear as day while onthe 12" subwoofer, the notes will start to bleed into one another and it will be less obvious that it is continuous notes and not one note.

I am a little different in my tuning methods and run a very long slope to a much higher frequency than most on my subwoofer lowpass. the slope begins at around 100Hz and drops off at almost 220Hz usually. I do not however, run my subwoofers without a slope all the way up to 200+Hz. I would end up with pure steady continuous bass as Im sure you know.

the problem is this. Both cars WILL get to 0.5mph and both WILL stop. however, the laws of inertia will cause the SUV to take off twice as slow and stop in at least twice the distance. regardless of how little the difference is... the difference IS there. and no matter how hard you tweak the engine and brakes on that SUV... you can tweak the engine and brakes on the car and the car will be faster again. Yes the difference is very small, but it is there nonetheless. (hence why I originally posted desputing the difference between the 10" and 12" subwoofer. I was not the original person that called them so different. I argued against it. However, there IS a difference... it may be small... but it is there)

btw... congrats on the trophy

 

Fine. We'll agree to disagree. I know there's no way anyone can tell a difference between a 10" (or smaller) and a 12" (or larger) - given the parameters I've specified: low crossover point, proper enclosure, etc.

Here's another pic of Robyn taking 1st place with her "slow" 12"s (wired mono), and able to hit 139.1dB LOL:

 

That's fine. Differences of opinionaside, we are kind of both working toward the same goal here; getting this guy some good advice for choosing the subwoofer that best suits his needs. I would say that based on his needs and wants from the application, he should go with the JL (if the JL and Focal were the only two options). If you aren't limiting yourself to those two brands, I would also recommend the following subwoofers:

[ul][*]JL 12w7 12" $599 new ($300 used) (450-1000wrms)[*]MTX T9500 12" $439 (1000 wrms)[*]Boston Acoustics G5124 $319 (450 wrms)[*]Image Dynamics IDMAX12 $449 (1000 wrms)[*]MMATS Dreadnaut 12" $449 (1000 wrms)[*]RE Audio MX12 $899 (1500 wrms) <-- kind of high power (but WELL worth it. OMG those things pound)[/ul]

 

Here's my list of top performing subwoofers:

BTW: RE was an excellent company. They've been sold (to US Amps), but the engineer's started a new company, Fi: www.ficaraudio.com The "Q" is awesome.

TC Sounds: http://tcsounds.com/

Critical Mass: http://www.criticalmassaudio.com/subwoofers.html

Oz Audio's Matrix Elite series: http://ozaudio.com/pages/products.html

JBL's "GTi" series: http://jbl.com/car/products/product_...UB&ser=GTI

 

Not too big a fan of JBL since the 90's... but the rest are very good drivers.
+1
I would add most of those to my list as well.