The light blue rectangles are proposed panels for first reflections, the green rectangle is what I have already. Is this sufficient coverage for center speaker(yellow particles) and right speaker(blue particles).

http://img.photobucket.com/albums/v308/Bloodta/reflection.jpg

Hard to say without seeing where the speakers are. Best is to cover a rectangular area a little larger than needed. Then you can move forward and back, and side to side, in your seat and always be out of the way from reflections.

--Ethan