[neekomax]

Sounds good. Have you inquired about cuts?

[srb]

Sounds good. Have you inquired about cuts?

No, they were closed.  Thought I'd give them a call tomorrow.  I could e-mail, but sometimes one answer prompts another question so I figured I could get it all with one call.
 
Steve

[neekomax]

Here's the little test diffusor in action in between the speakers... 

[richidoo]

It looks sharp! 

I'm at RobS' house, he has a huge 2D phase diffusor behind the listening seat, which is made of white foam (I think it's expanded polystyrene foam - Styrofoam) painted with tasteful orange latex paint. I looks good. The layer of paint hardens the outside layer so I would think the high freq reflection would be a little better than the raw foam.

The pool noodle polyethylene foam is softer than the polystyrene types like corning pink or blue foam or beaded styrofoam. I think the rigidity is important for the reflectivity and efficiency of the diffuser. I don't know why, it just makes intuitive sense that a hard surface reflects better than a soft surface.

Do you know about this diffusor design app?
http://www.subwoofer-builder.com/qrdude.htm

[bpape]

EPS can work very well.  We use it in our QRD and Grid Fusors.  Little to no absorption - which is what you're looking for. 

The round foam I have my doubts about simply due to the density and mass.  You also wouldn't want row after row similar assuming you're going to be exposing the round surface to the waves similar to a poly.

Bryan

[srb]

I have some additional information on the closed cell foam from Foam Express.
 
The cutting is done with a water jet machine.  Cutting a 48" X 72" sheet into 2" wide X 48" long strips (36 cuts) is a $26 cutting charge.  Shipping from MI to AZ is $42.
 
They actually list three types of closed cell foam and they are, in order of most rigid to most flexible:  Neoprene, MicroCell and Polyethylene (pool noodle).  The Neoprene is quite a bit more expensive than the Microcell - $125 vs. $89 for a 48" X 72" X 2" sheet.
 
The cost for the cut and shipped (to AZ from MI) Neoprene sheet would be $193 for 144 ft. of 2" X 2", or $1.34/ft.  This is the only source I have checked, and there may be other/better/cheaper suitable foam products available, possibly from some local foam fabricators.  In any case, if I were to go with a foam, I would prefer a professional cutting job rather than try to hack the stuff up myself.
 
Steve

[Hipper]

You could try cutting foam with an electric carving knife.

[srb]

You could try cutting foam with an electric carving knife.

I've done that and it works fine for packing, inside speaker cabinets and other non-visual applications.  For this application I would want absolutely perfect cuts as a living space architectural element, and professional cutting is the smallest expense of the whole equation.
 
Steve

[neekomax]

I've done that and it works fine for packing, inside speaker cabinets and other non-visual applications.  For this application I would want absolutely perfect cuts as a living space architectural element, and professional cutting is the smallest expense of the whole equation.
 
Steve

I tend to agree that it will be worth it to spend 26 dollars for perfect (hopefully) cuts.

Steve, how large a panel do you plan on building again? Where do you plan on placing it?