The precedence-effect fusion interval in real rooms far exceeds laboratory values

Evidence

The area under the “second-image” curve has been shaded. This is the real-world precedence-effect fusion zone for speech, within which any delayed sound will not be perceived as a spatially separate localizable event. This perspective is very different from most discussions of the precedence-effect fusion interval. Normally, only a single number is stated, and that number normally relates to direct and delayed sounds at the same sound levels. This is a correct description of the results of a laboratory experiment, but simply wrong as guidance about what may happen in the real world. — Toole, Floyd E, Sound reproduction- the acoustics and…, 621

Categorization

Category: Contrarian or Surprising Claims

• XREF: Connects to the reader’s broader interest in psychoacoustic models — the lab-vs-real-world gap is a recurring theme across audio research.

Related

• A 30-40 ms delay separates fusion from echo in the precedence effect (similarity 0.86)
• Precedence effect threshold curves hold stable across very different listening environments (similarity 0.85)
• Late-arriving reflections within the fusion zone are audible but merge into one directional image (similarity 0.85)
• The 30 ms fusion limit applies only to equal-level speech in hemi-anechoic space (similarity 0.85)
• Natural room reflections are too weak and early to please listeners of reproduced speech. (similarity 0.82)
• The precedence effect suppresses spatial identity of reflections, not their audibility (similarity 0.82)
• The precedence effect fusion interval lengthens with signal continuity (similarity 0.82)
• Precedence fusion suppresses spatial perception but never masks the delayed sound (similarity 0.81)
• Natural room reflections never exceed direct sound, so fusion never breaks down (similarity 0.81)
• Precedence fusion is not masking; all reflections remain audible (similarity 0.81)
• Reverberation extends the fusion zone in which reflections merge with the direct sound (similarity 0.80)
• Two identical sounds within 30–40 ms are fused into one located auditory event. (similarity 0.80)
• ETC spike heights correlate inversely with actual audibility of reflections (similarity 0.79)
• Precedence accumulates source information while late arrivals actively disrupt perception (similarity 0.79)
• Delayed identical sounds merge spatially until delays exceed 30-40 ms (similarity 0.79)

Broader Connections

• Both room reverberation and program reverberation extend the temporal fusion zone #corroborates (0.82) — Toole, Floyd E, Sound reproduction- the acoustics and…, 631
• The 30 ms fusion limit applies only to equal-level speech in hemi-anechoic space #qualifies (0.80) — Toole, Floyd E, Sound reproduction- the acoustics and…, 603