Why Does My Subwoofer Hum When Any Device That’s Connected To My Tv Is Connected To My Receiver?
I own a Sony STR-DG500 6.1-channel receiver, a Cerwin-Vega active subwoofer, and a Sony 55″ 1080p SXRD projection TV. When I connect ANY RCA cable (digital OR analog connection) to the STR-DG500 that’s connected to a component that has any sort of connection whatsoever to the television (DVD player via analog stereo OR coaxial digital; cable box via analog stereo; even my iPod via a docking station, if the video connector is connected to the TV) I get a horrible hum through my subwoofer. If I use an optical connection or disconnect the component from the television, the hum goes away. If I connect an audio-only device via any connection, there is no hum. Hum persists regardless of subwoofer phase, volume setting, or crossover freq. Any ideas would be appreciated – amp and sub have both been in for warranty service, but problem persists despite assurances from the local Sony-auth. shop that the problem was found, diagnosed, and repaired. Thanks.
What your hearing is most likely a problem with your grounds. Is your sub plugged into the same outlet as the rest of your system using a surge or power conditioner. If not you should look into getting one. If the sub is far away from the tv make sure its at least on the same circuit as the tv. You can also try turning off that circuit and pulling out the outlet and tightening down on all the screws that are connecting the copper to it, over time they do loosen up some. Worst case, you can use a ground lift bought at any hardware store to lift the ground on the sub or tv and that will also probably clean up the hum. A warning if you do this though, by lifting the ground if the device shorts out the outer chassis of it will become charged due to no ground being attached so dont touch it until it gets unplugged, its a very minor chance of that happening but it can.
You may or may not also noticed a wide horizontal “HUM” bar slowly traveling from the bottom to the top of your TV screen in addition to the hum from your Sub-woofer. This is normally caused by an AC ground loop originating from your cable box. Buy an AC three wire to two wire adapter and tape the ground wire or metal blade so that it does not touch any metal surfaces on your wall socket. Don’t put tape around the round pin that goes into the wall socket.
Plug the adapter into the AC wall outlet and then plug your TVs power cord into to it.
Turn the equipment ON and see if the problem disappears.If not, you may need additional adapters on your other gear specifically those with a three prong AC plug.
Good Luck!
Hard to say!!
Most likely its a GROUND, not feed back!!
Some how your not grounding something!!
The reason for it coming through your sub is easy!! Sub plays the lowest notes/HZ!!
So that would be the only place it could come from.
Do you have a sub-filter, this will help!!
Most likely you have a sort in an output connection, on the TV!!
FYI
Sony, Bose and other major brand names are not perfectly made. Price pressure from China, has drop the whole industries quality, especially Sony!!
Take it back for an exchange, ASAP!
Sounds like you have a ground loop hum somewhere in your system.
How close is your sub to the TV? If it is in close proximity, you should move the sub to the other side.
Not sure if you have your system wired correctly either.
How is you DVD player wired to the receiver? I would hook the audio portion directly to the receiver not the TV first, and if you receiver does not accept video or even if it does , I would have it wire the video portion of your DVD player to the TV for video only.