|Or building cross frames with cardboard plugs
Bob: I've considered all these, but I'm not sure which would be the easiest to manufacture. I'm thinking that the skylines out of foam or wood blocks would be the easiest, but a large skyline of wood 2x2s would be insanely heavy. I will refrain from the foam because of fire concerns.
I think the basic QRD is probably the simplest design to build, but I'm not exactly sure what I'd use as the well dividers.
The pictured 2-d QRD version in your link seems a magnitude harder to build unless there's some easy way I don't realize. I'm not much of a woodworker, so I'm thining relatively easy things to build, looks are not so much a concern as I can mask them with a fabric cover to match my absorbers.
I was also thinking some very simple polys, or just flat sheets of plywood tilted in different directions to help diffuse a little, and eliminate some flutter echoes, but I figured something like QRDs won't be that much harder to build, and provide more diffusion.
Haven't really settled in on final ideas yet, though.
I'm surprised I haven't seen any really good explanations on assembling QRD type diffusers anywhere, even on the studio design forums. DIY skyline designs from foam seem very easy, but I'd rather use wood, and that would weigh a zillion tons!