Quote:
Originally Posted by
rdgrimes 
Do a search for "ground loop" and try some of the usual methods for eliminating hum. Ground potentials are mystical gremlins, never assume anything. Any thumps or pops happening?
Yeah, I already did some research in that area...but the humming I experience seems to be related to my receiver because:
- all my electronic equipment (receiver, Blu-ray player, TV, subwoofer etc) is powered from the same power conditioner (Panamax) but the humming occurs ONLY when subwoofer is hooked to receiver, NOT when it is hooked to subwoofer output on the Blu-ray player;
- the humming always occurs when I turn the mute ON on my receiver and lasts always between 5-8 seconds then it disappears - so I'm able to reproduce it whenever I want;
- randomly, the humming is also noticeable when I watch a movie (or listen to the music) but NOT AT ALL when the subwoofer is powered but disconnected from receiver;
I guess I'll have to talk to Yamaha customer service since my receiver is still under warranty. Maybe they will give me some hints.