Sound Treatment - Diffusers


I bought a carton (contains 4 panels). They are fabricated from styrofoam, which is fine for their intended use as ceiling panel drop-ins, but it renders them somewhat fragile as they are easily dented and damaged if dropped or mishandled.

That said, it is a cost-effective approach as pre-made diffusion products get expensive really fast.

I came across plans for DIY diffusers at this site that published open-source plans if you want to attempt to build your own:

The design approach is based on building up strips of MDF as opposed to constructing wells, and so they look to be simple to construct if you have a decent table saw.


Being fragile aside, I am interested in how they perform. I would be mounting these on the wall. Their web site says that they can be painted with water based paint, so that might help the sturdiness a little.

I do not have a table saw, so the DIY route is not for me. Also, I like the fact that these are light weight, as I would like to avoid something heavy if I can.


Another option, they make a couple variations -


From what I can tell, they “work” fine, although I just bought 1 carton of 4 to check them out. To get full benefit, I’d need more, which I didn’t go ahead with because I wanted something more substantial.

I mounted them to the wall with heavy-duty Velcro tape so that they could be easily repositioned. Problem was, the velcro adhesive tore out hunks of foam when I went to move them. The adhesive bond to the foam was stronger than the cohesion of the foam itself.

If were to go ahead with more of these, I would adhere a thin sheet (1/4" or so ) sheet of luan plywood to the backsides with some contact adhesive to give a bit more structural integrity to the panel. That would offer more mounting options, as well.


How could something made out of styrofoam be a diffuser. Think your getting diffusion and absorption confused.


Not at all. The compressed surface is smooth and non-absorptive an so reflects sound.

Here is part of the description from GIK:

"The GridFusor© is made from EPS (expanded polystyrene) so it’s light enough easily mountable on walls, ceilings, etc. without the use of damaging adhesives or massive mounting holes while still providing excellent diffusion characteristics.

Incorporating a mirror-imaged pair of 13-root diffusors, the GridFusor© provides excellent diffusion from 600 Hz to 5,000 Hz and additional scattering below and above the diffusion range. The GridFusor© is light enough that no additional support is required for your existing ceiling grid and it’s light enough that insulation above can still provide broadband bass control."

I tried a carton as it represented an “inexpensive” way to experiment with some diffusion in different parts of my room… $214 for four 2ft x 2ft square panels vs $600 (and up) to duplicate the capabilities in wood construction. It’s a really, really clever idea if you are dealing with a drop tile ceiling in a basement room. I’d be all over this stuff if I was in that situation, as you wouldn’t need touch them once dropped in place. But they are a tad too fragile to stand up well to repeated repositioning and manhandling.

More info here:


Yea I don’t get it and reading through the site doesn’t help. Don’t see how it’s possible that this product can effectively diffuse sound. Maybe the coating has some effect. There’s no way this could compare to a true wood prime 13 diffuser. I know some people are down on Acoustic Sounds (for whatever reasons) but the recommendations are least based on proven science\math. If it works for you that’s all that matters - may be able to save some $ though…

EPS Foam:

“Uses of Polystyrene
Polystyrene foams are used for a variety of applications because of its excellent set of properties including good thermal insulation, good damping properties and being extremely light weight. From being used as building materials to white foam packaging, expanded polystyrene has a wide range of end-use applications. In fact, many surfboards now use EPS as the foam core.”


I’m sort of with you on this one. I’m sure the GIK product diffuses sound, the operative term is how “effectively.” Which is why I didn’t buy more of them, although I still think it’s a clever solution for a drop-ceiling environment where you can stuff insulation into the joists above the ceiling and then add drop- in diffusor panels over the entire ceiling. I once had a setup in an unfinished basement that had insulation in the ceiling and it was an awesome sounding room for bass , believe it or not . . .

Foley’s manufactured stuff is hideously expensive, but I’m a big fan of his videos and bought a DIY plan bundle from Acoustic Fields that included plans for a membrane bass trap as well as 4 or so different diffuser designs. On a flash sale for $29. The plans are well done and include detailed photos to guide construction. That said, the (free) plans at are based on a design that would be much, much easier to construct and the files come with detailed performance measurements. With these, I just might be able to get by with my circular saw and a good ripping fence.

To build the Acoustic Fields designs, I’d need to invest in a decent table saw, so I need to balance the cost of tools and materials against a (relatively) reasonably -priced solution like the wood diffusers from GIK:


I agree on the pricing - I don’t own any of Acoustic Fields stuff either. Just use as a reference. Great info and a great guide to room treatment. GIT is very liberal with the terms they use to describe and label their products. They don’t seem to have much in the way of treatment testing data either. Even their wood diffusers don’t seem to be true quadratic diffusers based on defined number of wells\sizes. Their stuff is inexpensive though.