Loudspeaker angular separation, not rear placement, drives spatial immersion

Evidence

When the extra pair of loudspeakers were deployed at several angles between ±45° and ±75°, as shown in Figure 7.7(b), the IACC results all moved closer to the target curve. Two things have changed: all four loudspeakers are in front of the listener, and they are at different horizontal angles. What is responsible for the improvement? From what was seen in Section 7.1.2 it is the difference in the angles that is the key—the average is ±60°, the most effective angles. — Toole, Floyd E, Sound reproduction- the acoustics and…, 725

Categorization

• XREF: Builds on the perceptual essence idea from Section 3.4; the angle diversity rather than channel count is the mechanism driving IACC improvement.