I have my Fios whole house DVR hooked up to a Sony 5.1 receiver that I have had for years. When I am watching CBS the main voice on whatever show is on comes through the center speaker with the other sounds coming through the side and back speakers and it sounds great. NBC, ABC and Wpix all sound really wierd because the main voice comes out of the right front and right back speakers. The center speaker now switches to a dull background noise from the show...almost like the back speaker should be. Has this happened to anyone else? Why do most chs sound fine and these three chs sound a bit off?