Loud humming noise from tv subwoofer?

Question

Ive got a subwoofer connected to my tv which comes with two little speakers that plug into the back of the subwoofer. Everytime I switch the subwoofer on, i keep getting a loud humming sound about every 3 seconds. Why is it doing this and how can i make it stop?

Answer 1

A humming noise from a subwoofer can originate from several sources - the AC electrical service, a ground difference between components, a poorly grounded coaxial cable from your cable provider, or even a radiant noise from other devices. Here are some steps to help eliminate this hum:

Disconnect the signal input wires from the subwoofer and turn it on. If the sub still produces a humming noise with no RCA or speakers wires connected to it, there is either noise on the AC line or an internal problem with the sub.

Try plugging the AC power cord for the sub into a different outlet. If it is plugged into a power strip, plug it directly into an unused wall outlet. If the noise still persists, this may be an internal problem with the sub.

If you have cable hooked to a VCR or TV which is also connected to your receiver, disconnect the coaxial cable at the wall. If this eliminates the hum, there is a bad ground on the cable service to your home. Your cable provider should be willing to check this for you.

Make sure that the input cable to the sub is high quality and in good condition. Try moving the input cable away from any other cables.