Destination America HD Audio goes up and down

One channel, Destination America HD, has had audio issues for years and I can't be the only one with this issue. After several cable boxes and 2 different HD TV's, it's still occurring. Almost any show, even when recorded to DVR, the audio goes quiet, then loud, quiet and loud. We're using HDMI with Scientific Atlanta HD Digital, TB is a Mitsubishi 60".

Anybody, any ideas?