Harmon Kardon Dvd Changer The Best How Do I Get Rid Of Feedback In My Speakers On A Pioneer VSX-816-K 7.1?

How do I get rid of feedback in my speakers on a Pioneer VSX-816-K 7.1? - harmon kardon dvd changer the best

I have many comments on my speakers when no signal or during breaks in the sound of my receiver. This seems to go when it can no TV signal or DVD player, but if it is a signal and the volume so strange, I get information about the speakers. Is there anything I can do to solve this problem? All my compontnts was using a fiber optic cable and I do not think that there is a question of the country. I have not heard any complaints from other reviews of this receiver, so I think it's solvable. Or should I just the Harmon Kardon AR240 ...