Scott R. Foster said:
Slats:
The treatment you describe is very lightweight for a room this size - I would add more corner mounted bass trapping, and I would use all 4" panels [no 2" panels] for the early reflection control - you could benefit from the additional LF control and the cost differential between 2" and 4" thickness is small.
Also, your rear speakers might work better if there were symmetric.
Have you optimized your sub location?
Will the 4" still provide enough high frequency absorbtion? One of the more annoying of the room is a noticable harshness in the highs.
I've given up on getting the sub right until I can tame the room some. Where it is now isn't the best for the main listening position but it is more consitant across all seating positions.
The surrounds are symetrical when measured from the front/rear walls and the floor. Are you suggesting having one closer to the listening position?
EDIT: Big detail I've left off
these are Definitive Technology speakers I got many moons ago ( BP20 mains, CLR2000 center, forget what surronds) and they are all Bipolar. In 2ch mode they have a very large sound stage but things get funny in 5.1. Moving your head 3-4" makes an audible difference when 5.1 is running.