Loudness grows when sound energy spills beyond a single critical band

Evidence

Figure 2.18 shows a plot of the subjective loudness perception of a sound at a constant intensity level as a function of the sound’s bandwidth, which illustrates this effect. In the cochlea, the critical bands are determined by the place at which the peak of the standing wave occurs; therefore all energy within a critical band will be integrated as one overall effect at that point on the basilar membrane and transduced into nerve impulses as a unit. On the other hand, energy that extends beyond a critical band will cause other nerves to fire, and it is these extra nerve firings that give rise to an increase in loudness. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 667

Categorization

• XREF: Connects to the earlier chapter on how the cochlea performs frequency analysis via standing waves — critical bands are the perceptual unit of frequency analysis. — connects to: Loudness rises once noise bandwidth exceeds the critical band at constant SPL.; Uniform exciting noise delivers equal intensity to every critical band — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1189; Loudness stays constant below critical bandwidth then grows beyond it — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 1034 (+8 more)
• corroborated: 3 independent passages support this claim — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 667

Broader Connections

• Spreading a sound’s energy across more critical bands increases perceived loudness without raising intensity #expands (0.95) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 665
• Wider bandwidth increases perceived loudness at equal sound pressure #corroborates (0.90) — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 868