So, I have a Denon AVR E400 receiver, and I hooked up a new center channel speaker last night and wanted to play something to test it out. I put on a movie through Plex (on Tivo Bolt connected via HDMI) that the info tab shows having 6 channel source audio - however, my receiver will only allow Dolby PL II (Cinema, Music, Game) or DTS:Neo 6 (Cinema, Music) as available surround modes. I was under the impression that both of these surround modes take 2 channel source audio and, through algorithms, they "create" additional channels. I was hoping to listen to the audio in 5.1 as it was originally encoded, but can't find a way to do so (to the best of my knowledge.) Am I doing something wrong, or am I confused about what these technologies actually are and what they do?