I have been having an intermittent problem with voices on HD channels. Previously, it was limited to sports events, in which the volume of the announcers was either low or non-existent. I could however hear the crowd noise and other noise from the event (sound of the golf ball getting hit, player talking to caddy, etc.) just fine. This has happened on both Sat and OTA HD channels, and only on HD channels. My wife DVR'd Desparate Housewives last night and the problem surfaced again. I have my 622 connected to a Sony Dolby Digital receiver via optical cable. Any ideas as to what could be causing this problem?