The precedence effect suppresses spatial identity of reflections, not their audibility

Evidence

Some people have mistakenly taken this to mean that the delayed sound is masked—it isn’t. Within the precedence effect fusion interval, there is no masking; all of the reflected (delayed) sounds are audible, making their contributions to timbre and loudness, but the early reflections simply are not heard as spatially separate events. They are perceived as coming from the direction of the first sound—this, and only this, is the essence of the “fusion.” The widely held belief that there is a “Haas fusion zone,” approximately the first 20 ms after the direct sound, within which everything gets innocently combined, is simply untrue. — , Toole, Floyd E - Sound reproduction-…, 840

The precedence effect is an assisting mechanism of spatial hearing (Litovsky et al., 1999). It suppresses the effect of early reflections in source direction perception. This helps to localize sound sources in reverberant rooms. — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 1497

Categorization

• DEFINE: Clarifies what the Haas ‘fusion zone’ actually does and does not mean — reflections are heard for timbre/loudness but not localized separately.
• XREF: Connects to Haas effect and echo suppression in audio engineering; also to cocktail-party effect literature. — connects to: The first arriving sound wave dominates perceived localization regardless of level — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 1564; Early reflected sound localizes sources while late sound becomes directionless — Eric J. Heller, Why You Hear What You Hear- An…, 2471; A 30-40 ms delay separates fusion from echo in the precedence effect (+8 more)
• corroborated: 2 independent passages support this claim — , Toole, Floyd E - Sound reproduction-…, 840; Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 1497

Broader Connections

• Room reverberation barely affects early reflection audibility but strongly elevates late-reflection thresholds #qualifies (0.85) — Toole, Floyd E, Sound reproduction- the acoustics and…, 630