Sometimes, on some channels, I get a clearly audible buzzing or static noise during some commercials that have writing on the screen (Phone numbers, addresses etc.) This is not an all the time thing, but when it happens it is very annoying. I have standard cable, no cable box, and have the system hooked up to my reciever. The TV is an older (9 yrs) Sony 27" Trinitron and made the noise before the Home Theatre was hooked up, and still does it now. Any suggestions?