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.



Thanks. Good info. I think you are mixing up me and the OP though, just fyi. My rear wall has 4 ASC sound planks on it directly behind my seat (6" apart) and is open on one side to the rest of the house and the other is curretnly (!) drywall. I'm discussing w/ GIK about that now and a few other things. He is suggesting thick bass absorbsion with deflection on the rear wall also. One issue is that I can't go more than 4" since that is also essentialy the wall to the hallway to our bedroom and can't stick out too much.

The good part is my room is very close I think to where I want it - just need to tame some highs.

I do have 4- 20" ASC tube traps in the corners. I also have 7 Stillpoint Aperture 2's.

So, do I really need to absorb the bass frequencies further?



I have a 48x56" Rockwool sound absorption panel installed into the wall behind my listening chair. Covered by a print of the Grand Tetons taken at 10,000' . 

In another room I was forced to vacate I had a closet the length of the wall behind. I put absorption on back wall of it and removed the doors. That extended the size of the room and the distance behind the listening chair. It was probably the best sounding dedicated room I have used.

Since you are familiar with ASC tube traps, take a look at Art Noxon’s suggestions.

I believe a couple tube traps with silver buttons facing the listener is what he would recommend behind your listening position. 

I read with great interest your situation. I also have a lumin x1. The footings are interesting

I think all the CDs should be arranged irregularly to improve diffuser capabilities. Do you have lots of sound treatment stuff in the room. I would remove it all and see what the furniture in the room is doing which is extremely important and always never really discussed.

You sit really far from the back wall which is ideal, no doubt the speakers are pulled forward.

No doubt you’re Westie offers invaluable diffuser and absorption benefits.

Don’t overthink it it’s not rocket science

Love your system


Thank you, you are too kind.

BTW, my Westie is named Westy. He really loves to lay between the speakers in the sweet spot.

The cd’s are arranged irregularly by the artist. Some groupings have many cd’s, some not so many and there are spaces between artists.

I have the speakers about a 1/3 out from the wall and I sit about 1/3 back from the speakers and then the chair is also 1/3 back from the rear wall. Although, that was mostly just a starting point until I dialed everything in.

This whole thought occurred to me because I really don’t listen to the cd’s anymore. so, I was wondering what to do with that wall if I removed them. I appreciate the very good suggestions that have been made by the community.


Art Noxon is the founder of ASC (Acoustical Sciences Corporation).

I learned a lot by reading his technical papers.

Ozzy, you may want to measure your room. If you don't have any WAF considerations and can treat as you please I would measure. 

My GIK rep had a great point which is that, although he rec that I measure my room to see what I'm working with - because it is the LR and I'm WAF limited, that it is less important. This is because even if the measurements call for certain treatments, if they don't look like they will look good in our LR, I'm not buying it.

That said, I'm not tech savy at all and every time I start watching a youtube vid on REW my brain turns to mush. Also, I don't have streaming so I don't have a good way to hook up my laptop to my integrated amp (Primaluna). Someday I'll make the effort when I have more time, but I don't now - but again, it won't make much difference anyway since I'm for the most part limited to panels with Guliford fabric (and not ones with diffusion over top).

It is a amazing that turning the ASC tube traps how it can affect the center image.


Sounds like you have a lovely space and you have treated it nicely. Do not over dampen the room.

Do you like the sound you are hearing? Do you believe there is an issue or are you thinking that if you remove your racks you just might create one?

Diffusion is already working on the rear wall due to the CD rack so I believe that is the direction to start with.

I would suggest a 6” thick 2x4 panel directly behind you flanked with two panels specifically designed for diffusion. Diffusion is best when they are placed approximately 8 feet from the listener which it appears you will have slightly more so they will work great there.

If I understand correctly the back corners have bass traps all ready so you should be good after the three panels are installed.

Enjoy and don’t over think this since it appears you already have a very nicely treated room.

Live End Dead End treatment works great in a recording studio when you are near field. I have found in my space if the front wall is too dead so is the music. I have bass traps in the from corners, absorption in the middle and diffuser panels directly behind the speakers. Works very well. My speakers are 55 inches out from the front wall measured from the front of the speaker and the speakers are rear ported so the diffuser panel scatters the sound from the port. Just one way to handle a front wall, there are many others, but the key is don’t over deaden the room.

Thank you that is very good advice.

You are right on. I like the sound I have but am concerned that when I remove the Cd's/rack the sound may change.

What about Stillpoints Aperture ll's. I already have 6 in the room, would a couple more of them behind me work well?


I believe if you place one Stillpoint Aperture II on each side of a 6" thick absorption panel that is set directly behind your listening seat on the back wall you will be set perfectly and won't notice the CD racks as being missing. Mount them so the centers are in line with your ears. The sound probably will be even better. This assumes you have those bass traps in the corners of the back wall.

You think I will still need the 6" absorption panels even if I use the Stillpoints Aperture’s?

Here is what Stillpoints Aperture Panels claim:

"The Stillpoints Aperture is the only acoustical product that will give you both absorption and diffusion at the first reflection points of a system. And you want both!"

  • The Aperture’s unique trapping system captures an area of waveform much broader than its small surface area would suggest.
  • The Aperture can be used to trap waveforms either facing the wall or, facing away from the wall.
  • The Aperture effectively increases soundstage width and depth. This is especially true for smaller rooms. (See the Michael Fremer review in Stereophile, Feb 2016.)
  • The Aperture will increase the dimensional perspective of the image structure.
  • The Aperture focuses music and voice without room boundary.