I have a Harmon Kardon 520 reciever and I use either Logic 7 or Pro Logic II when I am watching regular TV. When using either, my surround speakers seem to be working fine, you can hear them, but they are low, and every once in awhile the surrounds will get louder and stay louder. I hate to say they are cutting in and out cause they are always working, its just sometimes it cuts in stronger than usual. Is this common or should I get it checked out? Its still under warranty till October and I ordered from J&R. Would I have to send this away or does anyone know of a service department in Tampa, FL?