Adding rear channels to stereo does not improve spatial diffusion

Evidence

Tohyama and Suzuki (1989) looked at a few arrangements of two and four loudspeakers, comparing measured IACCs to those found in a truly diffuse sound field—an all-but-unachievable goal in the real world. Results shown in Figure 15.3a indicate, not surprisingly, that two-channel stereo did not come close to replicating the diffuse-field IACC. The real news, though, is that doubling the number of channels by adding a pair of loudspeakers behind the listener at the same angular separation did not really change anything. — , Toole, Floyd E - Sound reproduction-…, 1670

Categorization

• XREF: Underscores the same conclusion as the quadraphonic square deployment being a poor concept. — connects to: Adding rear speakers at matching angles does not improve spatial illusion — Toole, Floyd E, Sound reproduction- the acoustics and…, 724; Extra surround channels mainly aim at consistent localization and height illusion — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2227; Combining stereo cues produces spurious cues that confuse localization (+3 more)

Broader Connections

• Spatial envelopment requires uncorrelated ear signals, not a diffuse sound field #corroborates (0.95)
• Extra surround channels mainly aim at consistent localization and height illusion #corroborates (0.85) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2227
• Excess uncorrelated rear-wall sound can destroy the phantom center image #corroborates (0.85) — , Toole, Floyd E - Sound reproduction-…, 702
• Combining stereo cues produces spurious cues that confuse localization #corroborates (0.80)