Meniscus Audio has some interesting sub amps. I'm building speakers myself. Try to ignore the jaded among us, who've been to all the shows, seen it all, done it all. If you listen to them too much, it'll stifle your creativity. I think designing speakers is very fun and rewarding. More improtant than woofer drivers, perhaps, is if you can get a sub amp with continuously variable phase control, and not just a simple phase switch (I don't know if any exists). The "Titanic" driver is supposed to be pretty good. I need to e-mail a friend to see how his project turned out with those. I'll let you know.