The just-noticeable difference quantifies the smallest audible change in a sound

Evidence

At these frequencies a change of 10 dB in sound level corresponds to a change of 10 phons—which is a roughly a factor of two in perceived loudness. However, at lower frequencies the curves move closer to each other. At 63 Hz the relationship is about 7 dB for 10 phons, and at 31.5 Hz it is about 5 dB for double loudness. Small changes in sound level at bass frequencies are audibly consequential. — , Toole, Floyd E - Sound reproduction-…, 333 (#qualifies, via linked claim)

in fact it doesn’t register to my ears as a big change, another indication of how broadly tuned our hearing is. — George Michelsen Foy, Zero Decibels, 97 (#expands, via linked claim)

Subjective measures such as loudness, being human impressions, cannot be made truly quantitative, but there is a rule of thumb that seems to work: for a sound to be perceived as twice as loud as before, the intensity of the sound must be increased tenfold. — Eric J. Heller, Why You Hear What You Hear- An…, 143 (#expands, via linked claim)

Categorization

• XREF: connects to: The decibel unit is calibrated to the smallest perceivable loudness change — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 181; Minimum Audible Angle measures the smallest discriminable angular change — Dijk, Pim van, Physiology, Psychoacoustics and…, 3052; A 3 dB SNR just-noticeable difference corresponds to a 26% intelligibility change in listeners. — Dijk, Pim van, Physiology, Psychoacoustics and…, 5669 (+6 more)

Related

• The decibel unit is calibrated to the smallest perceivable loudness change (similarity 0.88)
• Bass frequencies need far smaller level changes to halve perceived loudness (similarity 0.86)
• The decibel multiplier calibrates integer changes to the ear’s just-noticeable differences (similarity 0.86)
• The ear’s amplitude sensitivity varies with loudness and tonal complexity (similarity 0.85)
• Perceived loudness doubles with every 10 dB increase, not every 3 dB of intensity. (similarity 0.84)
• Amplitude discrimination depends on relative loudness increment, not absolute change (similarity 0.84)
• The JND is the smallest intensity change the ear can discriminate (similarity 0.84)
• Just-noticeable SPL differences stay constant near 1 dB across wide ranges (similarity 0.84)
• The ear’s just-noticeable amplitude difference depends on signal type, level, and frequency (similarity 0.84)
• A 1 dB level change anchors the model for just-noticeable slow sound variations (similarity 0.83)
• SNR just-noticeable difference grows from about 3 to 3.7 dB at positive reference SNRs (similarity 0.83)
• Human hearing perceives huge physical sound intensity changes as barely different (similarity 0.83)
• A 1 dB level change marks a recurring just-noticeable unit in hearing (similarity 0.83)
• A 3 dB SNR just-noticeable difference corresponds to a 26% intelligibility change in listeners. (similarity 0.83)
• A 10 dB change roughly doubles or halves perceived loudness for complex sounds (similarity 0.83)

Broader Connections

• Human hearing perceives huge physical sound intensity changes as barely different #expands (0.80) — George Michelsen Foy, Zero Decibels, 97
• Bass frequencies need far smaller level changes to halve perceived loudness #qualifies (0.80) — , Toole, Floyd E - Sound reproduction-…, 333
• A tenfold intensity increase is perceived as only twice as loud #expands (0.80) — Eric J. Heller, Why You Hear What You Hear- An…, 143