I have a pioneer vSX-516 which I've had for a while. Unfortunately I've noticed a buzzing noise coming from the center speaker, not the other ones. When I disconnect the center speaker the noise is gone...However, i hooked up another speaker in it's place and it also buzzed, so its not the speaker. I have wire going from the speaker to the back of the reciver, about 5 feet. I use banana plugs for the back of the receiver. i've also replaced the wire... Any suggestions? Could my cable box be causing any problems?