I just bought a used KLH K-sub10, 10" 120watt sub. I am attempting to connect it to a Kenwood VR-209 reciever. I have tried several different connection configurations and have not gotten a response from the sub using any of them. I have used the sub RCA output, i have tried tying the sub directly in with the speakers (using the speaker outputs) and I have also tried doing both at the same time. I did get a little response when I plugged just the sub out in and turned my speakers off (just so I wouldn't blow them), then turned the reciever almost all of the way up. At this point the sub was making about as much noise as i would have expected with the volume turned all the way down. Adjusting the frequency and gain knobs on the sub also makes no difference. I wasn't sure if maybe there is something wrong with the speaker itself, but if anyone could give me some help i would appreciate it.