So I finally decided to start building something, while I can get my Tempest fixed. I took some MDF, 1.20 x 1.20 meters in size. Had a carpenter cut the required holes in it, semi-bolted 6 12" Cerwin-Vegas in them (HED-12, 22 Hz Fs, 17 mm Xmax, $60 each!), used one voice coil so as to have a Qts of 0.69, connected my PE300-794 amp to them with a 6-ohm total system resistance, and quickly burned a CD with test tones. Did I mention the test tones started at 10 Hz? I slowly turned up the volume on the contraption. I expected to hear plenty of distortion in the form of second and third harmonics on the 10 Hz track (I mean, $60 for some C-V drivers? I didn't expect too much). I looked at the drivers moving. No sound at all. Cranked the amp's volume up. The drivers started moving so far, I don't think I've ever seen cones moving like it. No sound whatsoever. Turned it up more. At halfway point, the drivers were moving like crazy - I guess they DO have 17 mm. Xmax - and no sound whatsoever is coming out of them. My body, though, is physically reacting to the sound. I feel very dizzy and my head hurts. I turn down the volume. Could it be? 20 Hz come up. The cones move like crazy, and a very faint low tone comes up. 40 Hz come up. The whole contraption starts jumping on the floor! Conclusion: 272 watts RMS + 6 drivers on an IB = possible path to sonic nirvana. Now, all I need is for my architect to finish up my house so I can mount the thing somewhere. I. Can't. Wait.