There are a few good 12" bass speakers that will work in a small sealed box, but none in 4 ohms. http://www.parts-express.com/pe/show...number=290-593 http://www.parts-express.com/pe/show...number=290-518 http://www.mcmelectronics.com/produc...500LF-/55-2845 http://www.mcmelectronics.com/product/55-2830
I had eyed the 12B as well, and it does model well, but the xmax of 2.4mm scared me off.
There's also a good amount of love for the Eminence Delta 12A for sounding great with bass and guitar. Again, 8 ohm only and also 2.4mm xmax, so it's going to distort early.
Hmm, actually side question to the gurus: would an xlim of 9.9mm for the 12A and 12B's make them feasible? You'd get plenty of cone breakup sure, but it won't bottom out for a while (it's 1.4mm more than the DL's xlim). What's a reasonable xlim to look for for this application? If so, yeah 12B all the way.