Dr. Toole's findings and review of the literature relating to side-wall reflections have been discussed here previously. This is covered at several points in his book "Sound Reproduction". For example, at pp.503-504 he states: "The matter of side-wall reflections of L, C,and R loudspeakers warrants some discussion because of the widespread belief that these reflections should be eliminated as a matter of ritual. The ritual had its origins in recording control rooms-listening in stereo-encouraged by alarmist cautions about comb filtering(see Chapter 9)or degraded speech intelligibility(see Chapter 10)or masking of other reflections within recordings(Olive and Toole, 1989). When examined, none of these turn out to be problems."
The importance of first reflections in creating spaciousness is emphasized and providing an area of blank wall at least 4 feet long "at the locations of the first lateral reflections" is recommended(p.504).
