Tom, it's only a 120w RMS (240w max) amplifier. I do have a crossover, and have it set up. The amp works fine, and you can tell there's a signal going into it (Pioneer put a light on it so you can tell when it's on/pumping sound), but there's nothing coming out of the sub. Could it be an Ohm discrepancy? My rear speakers are 2ohm, the amp is 2 as well, I believe, but I'm not sure what the sub is (the sub works on my 8ohm home stereo thought ???). Could that be the problem (need a new sub?), or do you think it's an internal amplifier malfunction?