Here is the link to the
Exodus Audio sub driver page. Hometheatershack has an excellent set of forums for subwoofer design and build including a link to WinISD, a driver modeling program that you can use to model various subwoofer drivers and enclosures.
Creative Sound Solutions is another good sub driver vendor. I see they have the SDX 10 on sale at the moment. Thats an excellent driver for smaller enclosures.
Although I have played with WINisd a fair bit, I have not yet built a DIY sub. In picking up the EP350, I made the 'mistake' of buying a very good sub the first time around that gets me 95% of the way to music Nirvana and 80% of the way to HT Nirvana. I have a hard time justifying another $700-1K it would take to best the EP350.
That said, the Malx-21 with a 1500w pro amplifier (and a VERY big cabinet) would get you more sub than almost any commercial sub out there.
