Thanks to all of you for your input. Compact size is really the key in my case. Montoya, I saw your ad for the MX 70B - unfortunately, its about 20 inches high and that's too tall for my space. I am now also considering the Gallo Acoustics MPS 150 - it has the big advantage that the amp section can be separated from the subwoofer - doesn't go as low as the M&K or the Sunfire, but it may do the job. The problem with the HSU again, is height - 32 to 52 inches depending on the model.
Sunfire True Sub Jr. VS. M&K VX-100
I need a compact sub and was wondering if people had any thoughts as to which one of these is better? I am mainly interested in finding out which one is better for music, although home theater is a small part of the equation as well. My room is large (cathedral ceilings etc. but the listening position is barely 8 feet from the speakers). My main speakers are PSB Stratus Bronze (which go down to around 40 Hz). Also, because of severe space limitations I CANNOT consider full size subs. Input on the True Sub MK II as well would be useful. THANKS!!