Echo Busters or Room Tunes?????????

red2's response is right on the money,audio asylum has several forums that deal with your problem.go to the rives room acoustics and also the planar speaker site.planars and electrostatics are different from other speakers in that they are dipolar[they fire to the rear also] different animals.
whatever you do...too much absorption behind these speakers kill the soundstage and deaden the sound.these speakers need diffusion materials behind them.sometimes a fake ficus tree behind each will do the trick.
good luck..check it out with the pros over there.

Echo Busters really helped my bright room slap echo aspects, and they add a nice decor look.

ACS Tuber traps had very little effect and dominated the room (and I didn't have enough to do it properly).

tom

Try realtraps.com - I just ordered some of theirs to try. I'll report back...

Elecrostatics are dipoles,right.I would suggest RPG skylines behind each speaker.I made mine and they are easy and inexpensive.Before you start to absorb sound try the RPG's.Then look for first reflections on the walls by sitting in your easy chair and have a friend slide a mirror down the side wall until you can see the speaker in the mirror from your listening position.That would be a first reflective surface.You can do the same for the ceiling if permitable.Once you diffuse the back and absorb the sides and ceiling.The back of the room may need some RPG skylines.Listen some more and if the bass sounds a little bloated roll some tubetraps from jon risch's web site.I use one 48"x18" in the front left of my room and one in the back right of my room.Good luck.