well I have a Captive Works 600S Premium but eventhough it has a S/PDIF optical output , therefore digital , it is only PCM 2 channel (of course this receiver has no HD capabilities). There is no option in the menus to change it to Dolby Digital though, like other tvs or dvd players will allow you. I can still use the onkyo to do some surround processing however. all channels are standard definitions therefore stereo sound.