I think I am having a problem with my receiver. There is a "popping" noise coming from all of my speakers. It is most noticable in my front left and right as well as center channels. At first I just assumed one of my speakers was going bad as they are 8+ years old. Does this sound like a speaker or receiver problem? The noise occurs when listening to CDs or watching TV. Is there anything I can do to test the system? I have a pioneer elite vsx-36t.