ISO standardized loudness-based noise metrics because A-weighting proved inadequate

Evidence

In order to have a better, yet relatively simple, measure of the perceived level of sound, the concept of sound level is defined as a measure that is weighted with frequency so that the level roughly approximates the frequency sensitivity of hearing. Four different weighting curves are defined: A, B, C, and D, as shown in Figure 9.3. The A-weighted sound level is commonly used in noise measurements to characterize the perceived level and the risk of hearing loss. The A weighting slightly emphasizes the levels at mid frequencies and attenuates them at low and high frequencies. When the weighting curve is compared with the inverted equal-loudness curves, it is easy to see that the A weighting is just a very rough estimate. Technical simplicity and extensive use in practice are its advantages. — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 988 (#qualifies, via linked claim)

Categorization

• XREF: connects to: A-weighted dB values misrepresent perceived loudness for complex sounds. — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1176; A-weighted sound pressure level misrepresents the loudness of broadband noises; Equal-loudness-contour weighting schemes failed as loudness meters (+10 more)

Related

• A-weighting is recommended for all sound levels despite fitting low levels best (similarity 0.94)
• A-weighting can miss dominant low-frequency energy in broadband sounds (similarity 0.92)
• Loudness meters use frequency weightings as a compromise because ear response varies with level (similarity 0.90)
• A-weighted decibels are a rough practical approximation of perceived loudness (similarity 0.90)
• A-weighted dB values misrepresent perceived loudness for complex sounds. (similarity 0.89)
• Loudness-calculating procedures outperform simple SPL for practical noise reduction (similarity 0.88)
• A-weighted sound level approximates perceived loudness only crudely, yet remains the noise-measurement standard. (similarity 0.88)
• Equal-loudness-contour weighting schemes failed as loudness meters (similarity 0.88)
• A-weighted sound pressure level misrepresents the loudness of broadband noises (similarity 0.88)
• A simple high-pass filter can replace elaborate loudness models (similarity 0.87)
• Loudness curves from anechoic pure tones fail on real broadband program material (similarity 0.87)
• A-weighted decibels better predict hearing damage than unweighted sound pressure level. (similarity 0.86)
• A-weighted SPL was a compromise standard known to give misleading noise results (similarity 0.85)
• Loudness scales with frequency squared, requiring large amplitude at low frequencies (similarity 0.84)
• A-weighting won general acceptance while B-weighting was abandoned (similarity 0.84)

Broader Connections

• Equal-loudness-contour weighting schemes failed as loudness meters #corroborates (0.95)
• A-weighted decibels are a rough practical approximation of perceived loudness #qualifies (0.85) — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 988
• Loudness-calculating procedures outperform simple SPL for practical noise reduction #expands (0.85)
• Loudness curves from anechoic pure tones fail on real broadband program material #corroborates (0.80)
• A-weighting can miss dominant low-frequency energy in broadband sounds #contradicts (0.80)
• A simple high-pass filter can replace elaborate loudness models #contradicts (0.80)
• Perceived loudness and physical sound intensity follow different, non-intuitive mathematical scales #expands (0.80) — George Michelsen Foy, Zero Decibels, 53