I had all of my primary reflection points (plus all corners) treated, but was lacking something for the front wall (behind and between the speakers). I was looking for some diffusers and came across this add on Agon for a company I'd never heard of before - PI Audio Group. Long story short I ordered a set of their AQD1 diffusors (4 diffusers that are each 2' x 4'). Each pair are the mirror image of each other (see pics) and they are shipped interlocked with each other. Upon contacting the company they allowed me to pic my paint color (for a small up charge) and had them cut, painted and shipped to me all within about 10 days. Greg at PI Audio Group was very responsive and very helpful.
Since I was receiving four diffusers, I decided to put the mirror image pair in the rear of my room (behind the listening chair) to replace the thin absorption panels that I had there previously. Those absorption panels were then moved to help control ceiling wall interface on the back wall.
Once installed i was very amazed at the slight but real improvement in soundstage (width and depth) and the significant improvement in image specificity and definition of "space'. I "thought" it was really good before, but now the exact location of instruments in an orchestra is much more evident and with greater front to back location definition (as well as left to right). There also has been an improvement in timbre with the room having less "glare" than it had before installing these devices. The glare reduction is subtle but very audible. Funny thing is that I wasn't aware that there was a tiny bit of glare - until it was reduced (go figure).
Here's the kicker. 4 2'x4' panels custom painted a shipped all for under $300!!! I am real HAPPY.
Quick Note: Greg at PI Audio Group said that they perfrom best (effective frequency extended down to near 200 Hz) if they are mounted 1" from the wall. So I did have to cut some 1"x2" strips to glue onto the back (w silcone caulk) in order to space them out from the wall. Fairly simple, but it was an extra step that took some time.
