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.