That's not a bad suggestion. The only thing that I'm a little uneasy about is the 20hz tune; I've always only considered ported enclosures with a 16-18hz tune. Does the driver play a role in the tune in a martycube, such as the SI18 vs the HO18 vs the UM18?
I'd really like to see the following 3 lines plotted if someone has time, in a 17'x18' room, approx 2400 cubic feet:
SVS PB12-Plus/2 (approx 425 watts per driver)
4 UM-15's, all in 3ft3 sealed enclosures with max power available to each driver
2 18's (I'm open to the SI, HO, UM) in ported martycubes with max power available to each driver
(I'm assuming the iNuke6000dsp would give max power to all drivers in both cases)
Seeing those 3 line plots together might really help me out.