Question: Sound Treatment behind the Listener?

I have treated the 1st and 2nd reflection points and I have sound panels between my speakers. I also have tube traps in all 4 corners, but I am not sure what (if any) should be done with the wall behind the listener.

That wall presently has a DIY rack system that holds about 5000-6000 cd’s. I believe it helps scatter the sound. But I’m not sure if that is the right approach.

So, what are you guys using on that wall? Diffusion, Absorbtion, Reflection? Anything else?

I would appreciate your thoughts.



Perfect, thanks. I'm thinking about moving my 242s to the rear wall but they don't have scatter plates - maybe I can buy those sep and then pull the staples out of the fabric and put those in and restaple. I'd probably make a big mess of things though.

That youtube vid posted earlier is excellent. I'm thinking about ordering  2D / GIK polys to put next to (new and larger) GIK 242 panels on my side walls. 

I just need to take a smidge of treble energy out of the room - not much but some - well quite a bit for some recordings but none to very little on others. Resisting buying an EQ.

Well, I submitted the form to GIK. Before being able to submit the form, I must say the constant need for showing that I am not a robot is annoying. Especially so for the GIK website. Why is that necessary?


I ended up going with GIK 6A Alpha diffusor/absorbers to go behind my listening position. Granted, my room constraints necessitated something that would work relatively nearfield which these do. Highly recommend these.

There is a rule-of-thumb (a formula in acoustical engineering terms) for how far one must be from the wall behind the listening position when using diffusion rather than absorption. I didn’t bother to memorize it, as it told me I couldn’t use diffusion on that wall, my currently situation requiring me to sit too close to be able to do so. I'll bet a Google search will lead one to the answer.