I tried using absorption on the front wall in my prior home and current listening room and did not like the dulling, lifeless effect.
On the front wall (behind speakers), diffusors tend to work much better than absorbers. I have about 65% of my front wall surface coverage using GIK Alpha 4a (1d). diffusers (even thicker, the Alpha 6a 2d) work very well on the back wall (behind the listening position). I have a combination of absorbers and diffusors on my side walls, and absorbers only on ceiling.