also remember with a 15, its only made for hitting lows. so if your considering it, dont plan on listening to any metal.
Thats not correct. A 15 can play anything, all depends on a box enclosure. And for your application i would do 2 sa-12s off a audioque 1200d and add another down the road.
right, my mistake, a 15 in a larger ported box wont play the notes from a double bass pedal very well...