I have one of the large pro bass bins (dual 15" 2226J drivers) and a older Sony receiver I am *trying* to use as the sub amp. I have tried EVERYTHING to make it work, but it won't. I can get FM radio and full range inputs to play - but when I go from the sub out on my receiver (Harman Kardon) to the receiver's input (any of them, done L, R, used a splitter for both L&R, done multi-channel input, etc.) there is no sound ever. What is going wrong? I am assuming the subwoofers output must be a lower level signal and the Sony is not picking it up. I am getting really frusterated as this is the sort of stuff I am good at. Speakers are all set to LARGE on the Sony receiver, so no issue with that. I even hooked up another speaker in case the receiver didn't like getting just one speaker (the sub) hooked up to it. Impedance is not the issue (8 ohms) Thanks!