The ear’s frequency response means quiet playback dulls bass and treble

Evidence

The loudness of sine wave signals, as a function of frequency and sound pressure levels, is given by the “phon” scale. The phon scale is a subjective scale of loudness based on the judgments of listeners to match the loud­ ness of tones to reference tones at 1 kHz. The curve for N phones inter­ sects 1 kHz at N dB(SPL) by definition, and it can be seen that the relative shape of the phon curves flattens out at higher sound levels, as shown in Figure 2.12. The relative loudness of different frequencies is not preserved, and therefore the perceived frequency balance of sound varies as the listen­ ing level is altered. This is an effect that we have all heard when the volume of a recording is turned down and the bass and treble components appear suppressed relative to the midrange frequencies, and the sound becomes “duller” and “thinner.” Ideally we should listen to reproduced sound at the level at which it was originally recorded. However, in most cases this would be antisocial, especially as much rock material is mixed at levels in excess of 100 dB(SPL)! — David Howard, Jamie Angus, coustics and Psychoacoustics, 617

Categorization

• DEFINE: Defines the phon scale as a subjective loudness measure anchored to 1 kHz reference tones.
• CANDY: The everyday fact that turning down a recording dulls bass and treble traceable to equal-loudness contours is an instantly shareable nugget.
• XREF: connects to: Ear frequency response varies with amplitude, especially at low frequencies.; The ear’s frequency selectivity is imperfect and worsens at higher frequencies — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 477; The ear’s frequency response is level-dependent, favoring mid frequencies at low volume (+4 more)

Broader Connections

• The ear’s frequency response is level-dependent, favoring mid frequencies at low volume #corroborates (0.95)
• Turning down volume suppresses perceived bass and treble relative to midrange #corroborates (0.90) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 626
• Ear frequency response varies with amplitude, especially at low frequencies. #corroborates (0.85)
• The ear’s amplitude sensitivity varies with loudness and tonal complexity #corroborates (0.78) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 648
• Bass frequencies need far smaller level changes to halve perceived loudness #qualifies (0.75) — , Toole, Floyd E - Sound reproduction-…, 333
• The ear’s frequency selectivity is imperfect and worsens at higher frequencies #qualifies (0.72) — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 477
• The ear generates phantom low tones absent from the actual signal #qualifies (0.72)