I just picked up a Def Tech Super Cube III (8" with two passive 8" drivers). I use it in my office with a pair of satellites (Def Tech Studio 350s) in a two channel configuration. I measured the installed performance (pink noise with an RTA) and found the trio to be flat, give or take a few db, from 25hz on up, except for a dip at 100hz. My room is relatively small, but the power output from the sub is much more than sufficient, besting the 50 watt/ch receiver driving the satellites by a wide margin. The new price was around $600-$700.