Loudness meters use frequency weightings as a compromise because ear response varies with level

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 (#exemplifies, via linked claim)

Categorization

• XREF: connects to: Sound measurement must be frequency-weighted because ears are not uniformly sensitive; Loudness depends on frequency, angle, duration, and envelope, not just level — Toole, Floyd E, Sound reproduction- the acoustics and…, 903; Equal-loudness-contour weighting schemes failed as loudness meters (+9 more)

Related

• A-weighting is recommended for all sound levels despite fitting low levels best (similarity 0.94)
• Equal-loudness-contour weighting schemes failed as loudness meters (similarity 0.92)
• A-weighted decibels are a rough practical approximation of perceived loudness (similarity 0.90)
• ISO standardized loudness-based noise metrics because A-weighting proved inadequate (similarity 0.90)
• Sound measurement must be frequency-weighted because ears are not uniformly sensitive (similarity 0.90)
• A-weighted sound level approximates perceived loudness only crudely, yet remains the noise-measurement standard. (similarity 0.90)
• Perceived loudness meters must weight frequencies as a compromise across sound levels. (similarity 0.89)
• No single frequency-weighting can accurately meter loudness at all levels (similarity 0.89)
• Loudness scales with frequency squared, requiring large amplitude at low frequencies (similarity 0.89)
• A-weighting can miss dominant low-frequency energy in broadband sounds (similarity 0.89)
• A-weighted dB values misrepresent perceived loudness for complex sounds. (similarity 0.87)
• Loudness depends on frequency, angle, duration, and envelope, not just level (similarity 0.86)
• Loudness perception is logarithmic, which is why decibel scales fit hearing so well. (similarity 0.86)
• A simple high-pass filter can replace elaborate loudness models (similarity 0.85)
• A-weighting, the legal noise standard, rests on dated single-frequency measurements (similarity 0.85)

Broader Connections

• The ear’s frequency response is level-dependent, favoring mid frequencies at low volume #corroborates (0.90)
• A-weighted decibels are a rough practical approximation of perceived loudness #exemplifies (0.85) — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 988
• ISO standardized loudness-based noise metrics because A-weighting proved inadequate #expands (0.85)
• Loudness is measured subjectively against 1 kHz reference tones #qualifies (0.80) — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1169
• A-weighted dB values misrepresent perceived loudness for complex sounds. #complicates (0.80) — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1176