Loudness increases when sound energy spreads across critical bands to fire extra nerves

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

Category: Causal Relationships

• DEFINE: Explains the mechanism by which critical bandwidth determines perceived loudness.

Related

• Widening a sound’s bandwidth beyond one critical band raises perceived loudness at unchanged intensity. (similarity 0.96)
• Spreading a sound’s energy across more critical bands increases perceived loudness without raising intensity (similarity 0.91)
• Loudness rises with bandwidth beyond the critical band despite falling pattern height (similarity 0.90)
• Loudness grows when sound energy spills beyond a single critical band (similarity 0.90)
• Loudness is the summed specific loudness across critical-band rates, not the raw spectral level (similarity 0.89)
• Loudness at high sound levels arises from excitation spreading across adjacent frequency bands (similarity 0.89)
• Widening a sound’s bandwidth makes it seem louder at equal total power (similarity 0.88)
• Critical bandwidth marks the point where noise loudness begins to grow with bandwidth (similarity 0.88)
• Loudness perception requires a tenfold intensity increase to double (similarity 0.88)
• The ear sums all sound energy within a critical band into one perceived item (similarity 0.87)
• Loudness grows with bandwidth via area tradeoff except at extreme levels (similarity 0.87)
• The brain processes sounds inside a critical band as a single lumped item. (similarity 0.87)
• Any sound narrower than a critical band produces identical loudness regardless of its width. (similarity 0.86)
• Wider bandwidth increases perceived loudness at equal sound pressure (similarity 0.86)
• Noise loudness is level-independent until bandwidth exceeds the critical bandwidth. (similarity 0.86)