In this thread I talked about sound problems I was having since I got a cable box installed to go along with my HD TV/Blu-ray DVD/home theater speakers setup.
The sound problem begins this way: sound is fine (sometimes for several hours), then all of the sudden it goes tinny and hairy, as if there’s feedback or something, and it gets worse and worse until the sound is unintelligible. The only way to remedy it is to shut down the whole system (all components) and restart.
I was using the ARC sound connection between the TV and speakers, and it was suggested that I try an optical connection between the two.
Did that, and all was well until it happened again even with the optical connection. While the sound was screwed up, I changed the setting from optical to ARC and the problem was still there.
does it happen with both cable and blu-ray source? your description makes it sound like a DSP or DAC/ADC is going wonky in one of the components; that it happens after a period of time makes it sound heat-related. You’ve probably got a defective component in there.
Thing is, if it’s a heat thing you wouldn’t expect a reboot to fix it, only a more lengthy shutdown. Regardless, if digital format sound is picking up interference something is wrong with a chip somewhere. If you have another tv or stereo you can plug the cable box into you could try various combinations to isolate which input or output has got the issue. Or you could just try to exchange the cable box for a new unit and see if the problem goes away. Switching cables isn’t going to cure this.
I don’t have another TV to test with, but I will try one last thing before dealing w/ the cable company: I have the optical cable connected from the cable box to the Blu-ray box/speakers, bypassing the TV altogether. I’ll see if that helps.
Optical connection between cable box and Blu-Ray box/speakers has been 100% good since I tried it. Apparently the cable-to-TV-to-speakers thing was what was causing the interference (both with HDMI and optical connections).