Was just given an Acoustic Pro Cinema surround sound system. Got everything connected, but now we have a buzz/hum coming from the subwoofer. It doesn't seem to be a ground issue (we've checked several different ways). Is there a way to check the soundboard inside the subwoofer, or should we try something else? Any help is appreciated.
If the noise coming from the subwoofer is always present (even when not connected with the audio source), the problem is either the subwoofer's power stage or the power supply (check for leaking/blown-up capacitors). If the buzz appears only with the signal presence, it can be either a bad audio cable or the same subwoofer power stage.