Jericho

Lately I have noticed a low hum coming from my subwoofer. Normally, it's fairly low, as its only noticable when nothing in the room is on and even then it's pretty faint. I've had the subwoofer for around 4 years, so I'm wondering if I just noticed this or if its been going on for some time. Any how, I could live with it. Until last night. Watching a movie, the sub made a weird noise and an extremely loud continuous hum was coming from the sub. It stopped after a minute or two, but has come back tonight and won't stop. I've disconnected the sub from any other components, so it's defintely something with the sub and not any cable. Basic question is, what the hell happened? Is the sub dead now, and what are my options? I'm basically a novice on the technical aspect of these things, so any suggestions are appreciated. I've obviously love to avoid paying for a new sub, but I'd obviously like to get it fixed. Thanks in advance.

Brian Shannon

If nothing is damaged it sounds like a ground loop problem.

http://www.epanorama.net/documents/g...oop/index.html

While ground loop is the primary cause of unwanted "injected" power-line noise, there are other noise sources that need to be mentioned.

Light Dimmers. Your innocent triac-based lamp dimmer is a major source of unwanted power-line noise. With dimmers, the noise is injected directly on the Neutral return (white wire) as well as radiating said noise. There is only one practical way to eliminate this noise source: Removal of all dimmers from your home's wiring.
Miswired Outlets. The possibility exists that you have one or more "miswired" AC outlets where the Hot (black) and Neutral (White) wires are reversed on the terminals. This condition can be immediately ascertained by using an "outlet checker" (Radio Shack #22-101 or equivalent). Any outlets determined to be "miswired" should be immediately corrected as it only takes one miswired outlet to "screw-up" every outlet.
"Lost" Saftey Grounds. This condition can also be determined with the "outlet checker". If your A/V equipment uses 3-prong (grounded) plugs, this condition can cause no end of trouble as well as expose you to potential shock hazzard. These outlets should be corrected ASAP for your safety and for the safety of your 3-prong A/V equipment as mentioned earlier!
"Motorized" Appliances. Refrigerators and freezers are prime noise-inducers. Unfortunately, there's nothing you can do to directly "quiet" them. If they're connected to "ungrounded" outlets you're "asking for trouble", both in terms of noise and saftey!
Radio and TV Emissions. We all live in a veritible sea of emitted RF radiation from sources (TV, radio, arcing switches, etc.). Unfortunately, there's nothing you can do to directly "quiet" these sources, though you can minimize their "effects

http://www.smr-home-theatre.org/Ground-Loops/

Jericho

The ground loop problem may explain the low noise I had heard as I have light dimmers on the same outlet, but not sure about this extremely loud noise that has persisted. I'm going to check a few things out, tinker with them, and see what comes of it. Hopefully it's not a component, but just some fluke problem. Thanks for the help.