digital design 9512 is a good choice as well, here is a link, but dont be fooled by thier very modest rms ratings. many of us pour over 10000rms into these subs for burps in spl competition. however these subs are some of the most accurate woofers produced. they are designed with sq and durability in mind. http://www.ddaudio.com/dd/gallery.asp
IMO Digital Design and SQ should never be spoken in the same sentence. to each his own I suppose.
you have no clue then i guess, dd built the woofers for walt disneys theaters. i respect your idea, however i think your opinion is a result of so many dd subs being used in spl. just because they're loud doesnt mean they arent accurate. check out this link on the 9900 woofers...let me know what you think. http://www.ddaudio.com/dd/caraudio/woofers.asp?series=9900b
iv'e heard and dealt with a 9912 before and with the right intstall it could sound great, the setup i did was for my teacher and an SPL setup also, for those of you who dont know these are pretty much the loudest woofers you can buy, I dident really get a taste of the sq, anyways though zac, he wants a sql setup now with the same sub and we're trying to come up with some designs, since your DD guy i was thinking maybe you could help, his vehichle is 2002 civic SI hatchback
ID Max works very well in sealed or ported. The DD subs are excellent for sound quality if you built the box for it, like Zac said, they have an SPL reputation and people tend to think that it's one way or the other. Remember that they are designed for ported boxes mainly, so if you're after sealed a different sub will likely suit your tastes better.