Thanks auxinput. My ESL (old Quads) and magnetic-planar (Magneplanar Tympani T-IV) speakers don’t splatter much sound on the side walls, having the dipole null on either side and being pretty directional at higher frequencies, with the tweeter strips pointed directly towards the listening position at the mid-point of the opposite wall. They will be 5’ from the wall behind them, so diffusion should allow the rear wave to blossom well (one of the best things about planars imo), no need to absorb it. I’m not planning on getting actual real diffusers, having enough LP’s (about 3500), CD’s (around 6000), and books (if I can fit them in!) in racks to pretty much cover the room’s walls.
Thanks for the link Brad, but I don’t see it on my screen. Is it just me?! I need only to cover with absorption the 4’ x 4’ space behind my head on the wall which the listening chair has to be up against, unfortunately, to be able to get the planar speakers 5’ from the wall behind them, a higher priority to me than the lp.
Appreciate the help guys---Eric.