Loudness curves from anechoic pure tones fail on real broadband program material

Evidence

Using the data plotted in Fig. 8.2 together with those plotted in Fig. 8.1, the equal-loudness contours of the diffuse sound field can easily be constructed. Equal-loudness contours for sinusoidal tones or narrow-band noises indicate the interesting dependence of loudness on frequency. However, loudness depends on many more variables such as bandwidth, frequency content, and duration. Consequently, it is too simple to approximate loudness level by a single weighting such as the A-weight.ed sound pressure level. Because A-weighting has a frequency dependence that corresponds to that of the equal-loudness contours at low levels, A-weighted sound pressure level approximates loudness level only for sinusoidal tones or narrow-band noises at lower levels. Therefore, dB(A)-values of noises or complex tones, or combinations of both, are misleading when used as indications of subjectively perceived loudness. — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1176 (#corroborates, via linked claim)

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 (#expands, via linked claim)

Categorization

• XREF: connects to: A-weighted sound pressure level misrepresents the loudness of broadband noises; ISO standardized loudness-based noise metrics because A-weighting proved inadequate; A-weighting can miss dominant low-frequency energy in broadband sounds (+7 more)

Related

• A-weighted sound pressure level misrepresents the loudness of broadband noises (similarity 0.95)
• A-weighting can miss dominant low-frequency energy in broadband sounds (similarity 0.91)
• A-weighted dB values misrepresent perceived loudness for complex sounds. (similarity 0.89)
• Wideband sounds are louder than narrowband sounds at equal dB SPL (similarity 0.89)
• ISO standardized loudness-based noise metrics because A-weighting proved inadequate (similarity 0.87)
• Loudness-calculating procedures outperform simple SPL for practical noise reduction (similarity 0.87)
• Wider bandwidth increases perceived loudness at equal sound pressure (similarity 0.87)
• A-weighting is recommended for all sound levels despite fitting low levels best (similarity 0.87)
• Loudness scales with frequency squared, requiring large amplitude at low frequencies (similarity 0.85)
• Loudness is the summed specific loudness across critical-band rates, not the raw spectral level (similarity 0.85)
• A-weighted decibels are a rough practical approximation of perceived loudness (similarity 0.85)
• Equal-loudness-contour weighting schemes failed as loudness meters (similarity 0.85)
• Loudness is not reducible to sound pressure level or signal power (similarity 0.84)
• Loudness meters use frequency weightings as a compromise because ear response varies with level (similarity 0.84)
• Loudness depends on more than physical sound intensity alone (similarity 0.84)

Broader Connections

• Equal-loudness-contour weighting schemes failed as loudness meters #corroborates (0.90)
• A-weighted dB values misrepresent perceived loudness for complex sounds. #corroborates (0.90) — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1176
• Wider bandwidth increases perceived loudness at equal sound pressure #expands (0.80) — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 868
• Wideband sounds are louder than narrowband sounds at equal dB SPL #expands (0.80)
• Loudness grows with bandwidth via area tradeoff except at extreme levels #expands (0.75) — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1288
• Total loudness is the integral of specific loudness over critical-band rate #expands (0.75) — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1250