Herman, it's funny, but now I also CANNOT find the DIY Room Tunes information on the Jon Risch site. Although, I can still find other sites discussing his creation.
Anyway, the material of choice for the fabric he found to be burlap. Just about every other fabric was too reflective to do the job of absorption. Ah, but these things should often BE reflective, yes? Yes! That is why on one side, the devices contain a layer of polymer that provides that. You end up with one side that will reflect well, and the other which will absorb well. You try both in your setting, and go with the one that suits your environment, needs, tastes, etc. best.
While polyester batting was listed as the stuffing material, several knowledgeable members here have steered me in the direction of long hair carded wool as being superior to that, as well as foam and fiberglass. One thing I didn't mention is that it is going to have to be mothproofed, which should always be done in these circumstances.
The hard part will be the methodology in testing the effectiveness of the project. I don't just want to throw everything up in the room and sit down and listen. Rather, I intend to do this in stages, judging the effectiveness and need of each area and device in my room.
Pictures are no problem...
