12 feet listening distance from the F/C speakers. Supporting two listening positions (large easy chairs), the rears of which are up against an open walk way access area leading to a door. No option to hang any surround speakers. Left side is up against a picture window with curtains. Right side is open to another walk way, with the wall 8 feet further away from the listening area than the window on the left.
I'm using a 6.1 setup, where the listening row is:
SL --> 3 feet --> 1st position --> 2 feet --> SB --> 2 feet --> 2nd position --> 3 feet --> SR.
Surrounds are cheap JBL surround monopoles. SB is on a stand; SL/SR are on bookcases. All are one foot above and one foot behind the listening positions, with the sides firing directly at each other and the SB firing straight ahead.
I use DD PLIIx Music when playing DD EX sources, as this spreads the SB channel to the two side speakers. As of result, any sounds directed to SB feel like they are coming from directly behind each of the two listening positions. Sounds directed solely to the two side surrounds are still pretty directional.
I have an 2011 model AVR that is Audyssey enabled. Timber matching the surrounds is not an issue.
Question is: by using DD PLIIx Music for movie playback, have I mitigated the setup restrictions as best I can for achieving surround effects? Or would dropping to a 5.1 setup, with the two side surrounds located in the same place as they are currently, and then upgrading to omnipole surround speakers give me the same surround effects, but with less localization of the surround channels?