Speaker Placement, Listening Room Design

Try Alton Everest or John Sayers.

Have you invested in a copy of Robert Harley's book, "The Complete Guide to High End Audio"?. Many of your questions about room design, diffusers, bass traps, speaker placement, etc are explained in this excellent work. It's a book I refer to on a regular basis. Chapter 4 "How to Get the Best Sound from your Room" covers much of what you're asking about. IMO, it's a must read and re-read for all those in this great hobby. Available at major bookstores or on-line (Acapella Publishing).

One recommendation that my hi-fi store gurus tell me is to install wall bookcases in your listening room. These will help to remove echoes and turn down the brightness just right. Thick carpet is another important material to have.

Start with the basics, thick carpet and a pop corn acoustical ceiling, room measurements that eliminate/cancel standing waves. Then start with various speaker placements, following the one third rule. After that try different wall and corner treatments. Book cases on the side walls work great but try to cover at least two thirds of each wall. After that, its tweak, tweak and more tweak. One neglected issue is the acoustic shielding of the turntable/arm/cartridge. It needs to be in its own 'black hole', meaning no acoustic energy should impact/reach any part of it.

Rives will do a complete consultation....starting with either a blank sheet of paper or with an existing room. This is the cost-no-object solution.