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 Vinyl Shadow for the info.

I'm getting some advice from GIK but also just started a dialogue with Jeff at HD Acoustics who I found when searching here. It won't be free but it will (should?) be unbiased and sounds like he knows what he is talking about....because I don't w/ acoustic treatment on the rear wall.

I have found the Acoustic Insider channel on YouTube to be a good source of information around treating your room.  He mostly discusses treatment for small home studios, but the theory still applies to a listening room.  

As far as I can tell, he's not selling anything.  He does reference a document you can download, and I have no idea if he charges for it or if that is a gateway to purchase other stuff, but I've never looked into that.

Thank you, I will check out those sites.

It sounds like GIK wants me to get 6 of the Alpha 6's. I'm not sure if $1500 would better the sound that I have now with the cd rack.

I may try some convoluted foam I have behind me first just to see if absorption is where I wanna go.


One of the things that I consistently hear in my research on acoustic treatments is that you can never have too much bass absorption. The problem is that you need really thick panels to get into the lower frequencies. If you use thinner panels, they will just absorb the higher frequencies (which has its place in making a room less reverberant or maybe comb filtering) but won’t help you with bass nodes or standing waves.

Even if you get thick absorption panels. they still absorb the top end so the theory is that you should just have the thickest absorption panels you can so that you get as much bass absorption as possible.

So if you decide not to get the Alpha 6s, try to make sure you make your panels as thick as you can. The Alpha 6s are six inches in depth with a scatter plate so the theory is that they would absorb the lower frequencies while providing diffusion for the upper frequencies.

And, in my experience, it’s so hard to tell. I mean, while I get controlling excessive reverb and reflections makes total sense on paper, there are so many options and so many people (including me!) who just repeat what they’ve heard without direct scientific experience it’s frustrating. But you have time. And it never hurts to try the free or cheap route and work your way up to more expensive things.

Good luck on this journey!

@charliech , do you think having Townshend Podiums would reduce the need for so much bass absorbsion? I still need to measure my room but when walk around the room I don't sense that much bass pretty much anywhere. That said, I still feel it in my listening chair when rocking out.....which is a good thing for ....for me anyway.