Mine has a low humming sound too when i connect it to my DVD player and PS2 unit, and the humming is continuous. The sound will not exist if I connect it to my laptop. I've checked with the user manual and it says in there that this humming is normal. I've placed my subwoofer unit an approximate 2 and a half feet away from my TV, DVD and PS2 unit and also away from any AC power source sockets. However, the humming sound still exists. Gotta learn to live with for now as the user manual states it to be a normal behaviour. Comments??