I have a mordaunt short premiere set of speakers, and a pioneer VSX 1015 amp. The sub is connected with an Ixos cable and a splitter so that the mono output from the amp connects to both the left and right inputs on the sub. My problem is that the sub is constantly buzzing when there is no signal to it. It doesn't do it while the amp isn't connected, and I have checked all the mains cables nearby and it doesn't seem to be getting any interference from any of them. Doea anyone have any suggestions as to what might be causing this?