If you guys really wanted to go nuts, create a
double bass array. That is where you cover one wall with drivers and also cover the opposite wall with drivers, but have one wall be in a delayed phase versus the other (depending on distance), so that one wall soaks up all of the output of the other like a perfect bass trap. What this does is creates a plane wave of pressure waves instead of having the subs be point source or even line source emitters. This pretty much gets rid of conventional room acoustics, so no standing waves or anything like that. Just the response of the transducers throughout the room. A
club in Austria tried this and supposedly the results were very good, flat response, 7 Hz extension, with 140dB dynamic range.