Anyone having trouble with the dish 811 Dolby Digital? There are times when i'm watching HD i'm not gettnig any sound. 811 is hook up to my denon 3801 via optical. 811 setting is on Dolby digital/PCM. So i check the optical and it looks ok. i switch the output on the 811 on PCM and i'm getting sound but not on Dolby Digital. Anyone experience this trouble? thanks for the help.