Smaller rooms drastically worsen envelopment at off-center seats

Evidence

Figure 8.12(b) shows that in a much smaller home theater the consequence of propagation loss is dramatically greater: still 0 dB at center, but 9.9 dB at the side seats. Those listeners will be localizing the nearby side loudspeakers as sound sources, and envelopment is sacrificed. — Toole, Floyd E, Sound reproduction- the acoustics and…, 837

Categorization

• QUESTION: Worth chasing: is 9.9 dB the point where side-speaker localization reliably dominates over envelopment across listeners, or does it vary?