The speakers are hooked up to an onkyo tx-8511. Two channel stereo. Im not sure I would call the sound distoriton. It sounds kind of like static, the sound an old record player might reproduce in the background while playing records, that is not quite as noticable but increases with volume. I'm pretty sure the receiver is functioning normally, but it is a refurbished unit. The electrical panel or service unit is not anywhere close to the stereo. Im stumped.