Room treatment with diffusion

[HIFI]

I wish to hear from anyone that has had experienced both absorbing and diffusion in first reflection area of your 2 channel audio room.  Did you prefer one over the other and why.

 

 I’m asking because I have not tried diffusion.

 

Thanks in advance

[ASRMichael]

Diffusion for 1st reflection points. Absorption for corners/ceiling.
 

Good information on GIk acoustic site.  

[MarkusBarkus]

@HI FI I have tried, and still have, many different treatments in my room. Perhaps 25 or so. I have mixed velocity based devices with pressure based treatments. I have a difficult room, that now sounds very good.

I agree with @ASRMichael that GIK site has a lot of info; however, while generally true, using diffusion for first reflection might be different in your room. 

 

Also, many diffusors are really "reflectors" that just bounce the sound around. That's OK too, but it depends on your room.

 

Regarding your actual question, I have GIK 3D diffusor/absorbers at first reflection points (walls) and absorption on the ceiling first reflection (two inch panels, four inches off the ceiling). Floor is a padded area rug. 
 

In my opinion, the only "true" diffusion I have here is a set of quad diffusors on the back wall, built from plans purchased from Acoustic Fields. They were complicated builds, but very good.