I am planning to build a few diffusors for some of the long walls and spots in my recording space I imagine are causing issues. I want these panels to be simple, cheap, and attractive (decorative and finished looking).

Based on that, I am split between two designs:

1) Quadratic Residue Diffusors:
http://www.soundcontrolroom.com/products/diffusion/qrd.htm
http://www.mhsoft.nl/Diffusor.asp

2) Wood Slat Diffusors:
http://www.soundcontrolroom.com/products/diffusion/woodSlat.htm

Either design would be doable for me in terms of woodworking, so difficulty of production is not an issue. Regarding cost, I imagine the MDF for the QRD would be cheaper than the pine for the wood slat, but that would be an acceptable difference.

As far as appearance goes, I am starting to lean towards the wood slat because I like the look and supposed "versatility" as Steven Klein puts it.

The difficulty is that, unlike QRD's, I have not found any specs on how to space the wood slats out or DIY these panels at all. I have also had issues finding info on how reliably these work across the spectrum and just how absorptive they are.

If anyone here has had any personal experience (or speculation on) using/building wood slat diffusor/absorbers, any info you could provide would be awesome.

Thanks,
Mike

I too would like to see more DIY information on building your own, most everything I have found gives the fundamental equations, but not just some straight forward examples with real dimensions. There are certainly issues on sprectrum with QRD, not to metion they can be quite heavy depending on construction. It would be great to have a sticky on some good plans, I would like to give it a try myself.

Anybody have any plans they would like to share?

If you want something easy to build and effective down pretty low, try a DIY polycylindrical. While not a 'diffusor' in the classic sense (doesn't scatter sound randomly), it can acutally have a smoother dispersion curve across a wider frequency range than a QRD.

They're really, really easy to make. Think about something that is made from a 4'x8' sheet of plywood bent and slid into 2 slats that have angled slots cut into them. Fill in behind with insulation and you're pretty well done. Bracing the edges will help but initially isn't necessary to see the benefits.

The trick with this is to make one BIG diffusor - like 6.5' wide with a large radius and maybe extending from the wall 8-10". This scatter sound evenly across the room dimension and is easily effective down into the lower vocal range (low hundreds of Hz).

For secondary diffusion, another similar but smaller poly can be placed on the side wall in the rear so that the dispersed sound from the rear large one gets (again) evenly dispersed by hitting the second poly.

Bryan