I have my DVD connected to the reciever via an optical link only. I tried playing a DTS disc (X2), but for some reason I could not select a DTS playback. The reciever would only give me the choice of "Dolby Digital" or "Downmix (Stereo)". I have my DVD player and the disc set up properly. Can anyone with experiece with NAD's give me a hand? What exactly is the difference between DTS and Dolby Digital anyway? Thanks in advance!