Home Theater Hacks

Hack #54. Remove Subwoofer Hum

A common subwoofer problem is hum—that low buzzing that seems to fill all the empty spaces in your movie soundtracks and annoys dogs and low-flying birds. Learn how to isolate the hum, analyze it, and remove it.

One of the most annoying problems you'll ever encounter in a good home theater setup is subwoofer hum. This most often crops up when you've got everything set up and calibrated, all your cables Velcroed together, and your racks moved back into their final resting places. Then, just as you get comfortable on the couch, something starts to hum. As annoying as this is, it's not going to go away until you locate the source of the hum and get rid of it.

Hum Created by Coaxial Cable

The number-one cause of subwoofer/speaker hum is the coaxial cable connecting your cable or satellite receiver to your provider (either through an inground run to a cable box or through a satellite dish). Here is how you test for this:

1. Turn your system on and get it to produce the hum by watching a movie. Pause your DVD or videotape so that the hum is all you hear.

   Tip

   Don't use a normal cable or satellite program for this; you're about to disconnect the cable that provides the audio and video for your cable/satellite feed.

2. Find the coaxial cable running from your cable or satellite receiver to your service provider, and while listening to the hum, unscrew the connector and disconnect the cable.

Did the hum stop or reduce by a large amount? If so, the cable you disconnected ...