Hi again,
Thanks for the time you took answering my various questions - much appreciated.
To answer your question about my room treatment strategy, I must admit to learning a lot along the way. In short, I used absorption for bass and diffusion+reflection for the mids/highs. This was a conscience attempt to keep reverb times across the freq spectrum about the same. Having a wall-to-wall carpet makes for an awful lot of high freq absorption so the hard diffusive and reflective surfaces help to avoid further absorption. When bass traps were needed I placed hard curved surfaces on them (i.e. hemi-cylindrical or poly fusers) so as to avoid absorbing the mids/highs. With a short ceiling height of 7' I opted for RPG Skylines and the upward angle of the side wall reflective boards help direct sound upwards to the Skylines; it helps raise the apparent sound stage height.
I also wanted as much flexibility in trying new things and in moving things around so I needed acoustical treatments that were adjustable. Each hemi can be moved closer or further from the wall, the reflective baffles (what you call diffusers) can open and close across a wide band of angles. Even the GIK D1 QRD-like diffusers mounted on the side wall reflective panels can be slid horizontally. Needless to say the permutations and combinations are endless and allow endless tinkering and measuring.
