[sam.spoons]

Memory foam is quite heavy but, I suspect, insufficiently porous to be an effective absorber. It might work ok as a limp mass but why bother, it's much simpler to use the acknowledged 'best' materials for the job. The other issue with memory foam is the construction of the frames, RW3/703 is sufficiently rigid to be self supporting making the frames much simpler to construct. The optimum density mineral wool for ease of use and best absorption is around 60 kg/m3. My frames are extremely simple, just a perimeter of 2' x 1' PAR softwood butt jointed with a couple of screws in each corner, inside dimensions a fraction under sized so a 1200 x 600 mm mineral wool panel stays put inside. cover with suitable fabric and hang em on the wall/ceiling. Happy to post a diagram if it might help.