Panel placement for rear wall reflection problem

FWIW I always thought that the reason for bringing your speakers out into the room was fundamentally to reduce excess bass caused by rear wall reinforcement, not to reduce the magnitude of higher frequency reflections off the wall caused by speakers (although that can be a side benefit especially with dipoles). To answer your question, the panels should be placed on reflection points just as you would do for side wall reflections, essentially between the two speakers, not necessarily behind them. Another thought, is the use of dispersion for the back wall as opposed to absorbtion. Many folks prefer this manner of dealing with high frequency reflections, including myself, to deadening the wall.

Newbee,
That might well be the case, I am a little new to trying to control room acoustics. I know two things: I have a pretty bright room and my speakers are a lot closer to the back wall than recommended. They are monitor type speakers, so excess bass reflection may not be a problem (the rest of the system is on the way, any day now, so I can't say for sure yet). In the end what I will do is just use trial and error. I'm just trying to get some idea before I go stabbing around in the dark.

Jb3, Trial & error is the only way to go, but many folks here, including myself, have a lot of pratical experience dealing with room acoustic's, but other than answer your specific question, its tough to help without further information about your "bright" room. If you want more help tell us about the size of your room, the size and location of doors, windows, openings. The location of your speakers in realtionship to the side walls and the rear walls and your listening position. Also include floor and wall furnishings and furniture such as bookcases, chairs sofa's etc. The more information you give the better the quality of the comments you will get.