JohnE

To everyone: Well, all are interesting answers, but Peter hit the nail on the head. What happened was the stand-by circuit in the subwoofer was going and poof, it was gone including the amp inside the sub. Hey, I got fifteen years out of it so I'm not complaining. These built in amps don't last forever (we can only wish). Luckily I have a backup sub and I'll use that until I can get a new amp to fix the Klipsch with. Funny as the backup sub is a 20 year old JBL and I had to re-build it with a new amp. Now I'll re-build the Klipsch and go from there. Hopefully Klipsch still has an amp to fit, but if they don't there's tons of these amps on the market, one of them will fit. Bottom line, the auto-on/off was bad and that led to the amp going. And as Peter stated, there's voltage coming out of the receiver even in stand-by. So that was enough to trigger the auto-on/off and make the sound. The amp fried with it. Thank you all for some insight into this problem...

Peter.. The receiver is in stand-by mode, but automatically turns the master volume setting to off when you turn the receiver off (stand-by) which is a heck of a good idea by someone that designed it so you don't forget to turn the volume down before turning the amp back on. The subwoofer (it self) has a volume setting of a bit over half way. This was an incredibly loud sound. Worse than white noise. Anyways, I believe you've got a good idea. Never thought of unplugging the cable that drives it. (Just pulled the power to the subwoofer to stop it.) I'm using a pre-made Monster cable to run the sub (and yes, auto-on). I'll give this a try over the upcoming weekend and see what happens. This (as you said) would prove the theory. A much appreciated answer and will let you know what happens.

I have a older Klipsch RW-12ii. Fifteen years and still working fine. Problem is the past two nights the subwoofer has activated in the middle of the night and sounded like a huge white noise or gurgling sound. Woke me up immediately. Ran to the stereo system and everything was fine except the subwoofer was "sounding" off. I unplugged it, waited, and plugged it back it and the sound stopped. Everything I check in the system is fine, no problems. The next night the same thing happened, only at a different time. What I'd like to know is, can an outside (electrical or radio RF) signal could trip the auto-on feature??? (Or anything else someone could think of to cause this?) The subwoofer and all of the stereo is plugged into a surge protector. Nothing else was activated but the subwoofer. Weird! Has this happened to anyone else?