Quadratic Diffusers

I have 6 RPG diffusors behind my system and they may be causing me a bit of a problem. I am going to put several sheets of absorption in front of these to see if this helps the problem in my room. Leaving an adequate distance between the diffusor and source should be critical. 

I was at CES when the HFT type devices were introduced by I think a guy named Frank Chang. This may have been one of the first showings in the U.S. In any case they definitely change the sound, but I havent had them in my room so I cant say if they harmed or helped. I am a bit skeptical and would source them from someone other than S.R.

Thanks to mijostyn for the lead on the tiles. I am going to check these out.

I have a number of RPG Skylines (2' X 2' X 4") and a number of RPG which are (2' X 2' X 6"). The larger ones have a few missing pieces but the Skylines are perfect. These are made out of a sort of styrofoam material. Feel free to contact me directly in the event I decide to sell. Through the years I have accumulated enough material to do a few rooms and it is taking up space.