Alan,
I went through exactly what you said. The RCA cable is hooked in the adaptor and it is solidly plugged in. I then went through the set up procedure and was not getting any sound through the subw. I've checked and said yes to subw in setup, set to +2 and nothing. I guess my next question is, do I have it plugged in right on the back of the AV unit..R872? Connected to the Pre Out SubWoofer? By the way the was it is set now there was no loud noise like you would get hooking up a jack to an electric guitar for example to its amp.