I hesitate to post this, because it might therefore recur and doom my future experience. I hope I am not too soon in declaring victory.
I have had a problem with TV sound for about the past 6 months. The symptom was momentary sound dropouts (less than one spoken syllable) that recurred cyclically several times/second for maybe 10 seconds, maybe more. The infernal thing is that it would not start to happen until having watched TV for about 30 minutes, not before. Then it would recur at irregular intervals thereafter, destroying my pleasure. All other audio or video via JRiver has been pristine and exemplary, including hi rez audio and BDvideo.
But, I just got through a whole football game and some more TV watching without it. I do not watch all that much TV, so this has not been a "priority" problem for me, annoying though it was. Hopefully, it is not too soon to celebrate. The answer seemed to be to uninstall Norton antivirus (free from Comcast) and install Webroot, in my case.
Ok, I am using HD Homerun Prime with a Comcast Cablecard on an Intel I7 PC with Win 7. I have no idea how or why the antivirus should have affected this, but I do not care that much as long as the problem us solved.
Oh, yes. I was also having problems getting the EPG in 21. I was able to navigate Norton to fix that problem with mc2xml, but it was a pain for awhile until I discovered the answer. I do not see a similar problem with Webroot, so far at least.
Other antivirus packages might be just as good. The point is, as we have seen many times elsewhere in this forum, antivirus may be the cause if you are having problems.