Alpine "S" Series Subwoofers or JL Audio subwoofers? have any of you had any experience with either or? I will be running a 750watt MTX amp to the subs and I would like to get some input before i buy the subs

What model JL audio? What kind of music do you listen to? How much money are you looking to spend? Think about porting it into the cabin, otherwise you'll be getting some nasty rattles on the back deck.

Why limit yourself to those two? There are lots of great subwoofers out there, and many of them are significantly cheaper, better-sounding, or both than the Jello or Alpine offerings.

Four examples:

1) Adire Audio Brahma
www.adireaudio.com
Pros: Sophisticated motor design, exceptional quality.
Cons: Pricey, silly dustcap logo, requires lots of power.

2) Lamdba Acoustics
www.lamdbacoustics.com
Pros: Superior motor design and peerless attention to detail. His Apollos are the best woofers money can buy.
Cons: Nick doesn't suffer fools gladly, so you have to know exactly what you want.

3) Dayton Titanic/DSQ
www.partsexpress.com
Pros: Basically a Lamdba motor, albeit without the Faraday ring that so lowers the inductance of the Lamdba lines. Extremely good value for the money.
Cons: Not as sophisticated as the Lamdba or Adire motors.

4) Peerless XLS
in the US, www.partsexpress.com or www.madisound.com, corporate site www.d-s-t.com.
Pros: Used in US$20k speaker systems, and especially for Europeans probably the cheapest option.
Cons: Again, not as sophisticated motors as the Adire Brahma/Tumult or the Lamdba, so distortion will be higher.

Frankly, I think road-noise would swamp a lot of the motor differences, so my personal choice for a car woofer would be the Dayton, followed by the Peerless.

Jay

PS: Lest you think I used "Jello" as an insult, you're wrong. I've built excellent home and car subs around their woofers, and I called them "Jellos". However, the fact of the matter is they've been passed by.

A couple other more mainstream units, which still perform well, are the Infinty Kappa Perfect, Audiomobile, and Soundstream Exacts. Good subs are NOT cheap, expect to pay ~$250-$350 each (although I snagged a couple Perfect 12.1's on closeout at SoundCity.com for $165!)

Most importantly, whatever sub you buy, you MUST use the EXACT size box recommended by the mfr or you will NOT get the most out of the sub! Every time I have built the box properly the output is awesome.


Regards,

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Actually, I disagree with you there. Mfg's often recommend enclosures that are comically small, leading to a higher-than-desirable value of Q, and hence a boomy sound that has little to do with the reproduction of real musical insturments. High Qtc subs are harder to blow up, because the box artificially limits low end response. Also, they produce a spike in output in the 80Hz range that may make the woofer "thump" harder but has nothing to do with what was originally recorded on the disc.

JL in particular is notorious for box rec's that lead to indestructible subs at the cost of fidelity. (I've sparred with Manville Smith of JL on this topic a number of occasions, and we're reasonable people who simply agree to disagree on the issue.)

So how do you get it right? First, individually measure the Thiele-Small parameters of each driver. An easy way to do so is to buy the "Woofer Tester" at www.partsexpress.com. Why test individually? Manufacturing tolerance, and different atmospheric conditions from where the driver was originally measured.

Furthermore, companies are likely to take people seriously if they have a problem with their woofers if they can back up those problems with hard numbers. Once I bought a pair of Image Dynamics IDQ-12 woofers (very nice woofers that genuinely sound good in small sealed boxes because they have low-Qtc, but that technically are obsolete compared to the Adires, Lambdas, and Dayton Titanics of the world) with widely disparate measurements. I spoke to Eric Stevens of ID about my problem, and his answer was simple and refreshing: I'm sorry, pick the one you like and I'll hand-match a new one to its specs.

Once you've done that, then put those numbers into a box-design program. There are lots of good ones out there, at prices ranging from free to thousands of dollars. I prefer lspCAD, which is pricey but does stuff that the free ones don't. (If you're not into DIY home speakerbuilding, you don't need the power of lspCAD.)

The best compromise between sound quality (value of Qtc approach 0.5, or EBS alignment of vented speakers) and box size, is after all, the one you pick. I tend to build car subwoofers as sealed boxes with Qtc in the 0.577-range, and home subwoofers as EBS (low-Q) ported enclosures.

Getting it really right takes more effort than just doing what the marketer of the drivers tells you (very few build their own), but the sound is worth it.

it would be much better to take out the stock rear deck and build a new one out of wood wrap it in nice carpet cut a hole for where the med kit existed and drop a 8inch FREE AIR sub it must be a free air and then run a mono amp you dotn need a huge sub in the trunk to rattel the hell out of your car if you want sound proofing screw that dyno matt crap its BS go to Home Depot and ask for Quick Roof its the same stuff and absorbs sound jsut as good i used it on my car its amazing and i dont mess around good luck