I am new to home theater and to this forum, but I'm hoping you can help me out. I just set up my new Panasonic 50" plasma, Pioneer VSX-914k receiver, and got my HD box and cable service. I am getting some type of interference that is showing up as a hum through the subwoofer, and as white horizontal lines scrolling up the display screen. Here are some key observations. If I route my component cables directly from the cable box to the display, the problem is much less, but when routed through the Pioneer receiver, it is unbearable. I thought it was a problem with the receiver, so I returned it and bought an Onkyo sr602, set it all up, and had the same problem. Why are the lines so much worse through the receiver? How can I get rid of them? Is there some type of power filter I can buy that will eliminate this? Any help would be appreciated. Thanks.