Diffusors for front wall behind 3.6Rs?

[Mike Anderson]

I'm looking for some sort of material to put on the front wall just behind my 3.6Rs for diffusion purposes. I like this concept:

http://www.acousticalsolutions.com/p...pg_skyline.asp

but it's pretty expensive.

Any ideas for something along those lines, but less expensive?

Or any other entirely different suggestions, for that matter?

thanks