When running in 6.1 should I combine the left and right surround back outputs with a reverse splitter or do they have the same output? I currently use DTS ES and Dolby Digital EX via the optical input. I plan on using the 7.1 input with a Blu-ray with internal decoding in the near future. When running in Dolby True HD and DTS HD, are the surround back channels discrete? Thanks.

If I am not mistaken, when you go into your set up menu, you have the option of indicating one of the following for surround back channels : none, one, or two. If you are just running the single surround back speaker, you just set it in the menu.

In regards to the other question, "When running in Dolby True HD and DTS HD, are the surround back channels discrete?"

That would depend on the individual BD. Some discs are encoded with 5.1 (DTS or Dolby) while others are encoded as 7.1. For example, Weeds, is one of the few BD discs that I know are in 7.1, while most other movies are only in 5.1 (Dolby/DTS HD). . If you want the surround back channels, you can apply PLIIX. But again, this is done in the menu first by indicating that you have a single rear surround speaker.

If you playing a 5.1 (Dolby/DTS HD), and you apply the PLIIX, the channels are not discrete, the processing just takes the surround channels and creates some ambiance for the rear surround channels. That is what PLIIX is designed to do. Personally, I prefer it to using other DSP modes (for eg. DDEX). If the disc is encoded in 7.1, the rear surrounds are discrete.