Hi all -- Please bear with me, as I know very little about electrical issues. I have a new home theater system with 2 powered subwoofers. I noticed that one of the subwoofers had an audible hum (not all the time). I tried isolating components to see what might be causing it. If I disconnect the HDMI that runs between my DTV C41 and the receiver, the hum disappears completely. I think it might be that my dish isn't grounded properly. Dish is mounted on a metal pole that goes into the ground. The coax goes from the dish to a wiring center in my basement. It does not appear to pass through a grounding block. There is also a small ground (I think) wire attached to one of the nuts on the dish and run alongside the coax to the wiring center. The other end of this small wire is not attached to anything. Any suggestions for what I can do to improve the hum situation? Thanks!