There are two earlier threads on this issue, both locked. I'm starting a new thread because I have the same issue, and neither of the two previous threads resolves it.
http://forums.cox.com/forum_home/tv_forum/f/4/t/2501.aspx
http://forums.cox.com/forum_home/tv_forum/f/4/t/3758.aspx
I have the exact same issue. If I just press pause, I get the buzzing. If I press rewind and then pause, there is no buzzing. To me, this clearly indicates the issue is with the 9865DHC.
I have another, probably related issue. Sometimes the audio gets out of sync with the picture. If I go into the 9865HCD settings, switch the audio from DD to PCM and then back again, the audio is in sync again. This also clearly indicates the issue is with the 9865HDC.
I'm wondering if there is a solution to these issues. It seems the solution will come in the form of a software (firmware?) upgrade on the 9865HDC, as that's where the problems clearly lie. Given all the other people with the same issue, there is no point in having Cox swap out my box. I wonder if Cisco updates the software, can Cox push it out to our boxes automatically? Or is there some way to boot the box into some sort of maintenance mode and pull down a firmware update?