Wider bandwidth increases perceived loudness at equal sound pressure

Evidence

The loudest sounds, when presented at equal SPLs, are in the 2 to 6 kHz range. • Loudness depends on stimulus bandwidth: For bandwidths greater than a critical band, loudness increases with increasing bandwidth, a phenomenon called spectral loudness summation. A sound can be loud because of a high sound level or because it has a broad bandwidth. • Weber’s law predicts that the just detectable amount of intensity is proportional to the intensity of the sound (DI/I = k). Weber’s law holds for noise at moderate-to-high levels but not for low levels or for tones. Tones exhibit a near miss, in which DI/I or DL decreases with increasing intensity. — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 868

Loudness changes with bandwidth are greatest at moderate stimulus levels. The rate of change of loudness with bandwidth was not constant across levels. It was most rapid for the moderate levels and less rapid at high and low levels. — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 766

Figure 9.16 The perceived loudness as a function of the frequency bandwidth of the noise stimulus. The critical bandwidth is defined as the point on the curve above which the perceived loudness starts to increase. The centre frequency in this example is 1 kHz, and the width of the critical band is measured to be 160 Hz. — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 1037

There is no question that the uniform exciting noise produces a much larger area than the narrow-band noise, even though the overall sound pressure levels of the two noises are equal (64 dB) in both cases. Judging the ratio of the two areas, we can see that the uniform exciting noise produces a loudness that is about 4 times larger than that produced by the narrow-band noise, in agreement with the measured data. — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1258

Categorization

• DEFINE: Defines spectral loudness summation and the near miss — both key concepts for understanding loudness perception.
• XREF: Relates to the general principle that loudness depends on critical-band spread - same theme as why narrow filters do not sound as loud. — connects to: Loudness rises once noise bandwidth exceeds the critical band at constant SPL.; A-weighted sound pressure level misrepresents the loudness of broadband noises; Loudness stays constant below critical bandwidth then grows beyond it — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 1034 (+11 more)
• corroborated: 6 independent passages support this claim — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 868; Jennifer Lentz, Psychoacoustics- Perception of Normal…, 766; Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 1037 (+1 more)

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
• Loudness depends on frequency, angle, duration, and envelope, not just level #expands (0.80) — Toole, Floyd E, Sound reproduction- the acoustics and…, 903
• Loudness depends on more than physical sound intensity alone #qualifies (0.75) — Dijk, Pim van, Physiology, Psychoacoustics and…, 2610