I have unplugged everything that could be on the same circuit. still a low hum and vibrating subs.

no dimmers nor any fluorescent lights.

The fact that the problem did not go away when I moved the equipment to another room and again with trying a different receiver is (mis?)leading me to believe that it has something to do with the sub...

Just wish I could find my ground chassis screw so I could check that.

- Majik

Epic 80 system
Ep 800
Denon 3808
Optoma HD20
PS3
vp180
extra QS8s (to come soon)