Loudness is a subjective percept standardized against 1-kHz tone levels in phons

Evidence

In a common implementation of the loudness balancing procedure, we measure the level of a sound of interest (the test stimulus here) that matches the level of a 1000-Hz stimulus (the reference stimulus). For these studies, a 1000-Hz tone is always the reference sound, and it is presented at some fixed stimulus level (e.g., 40 dB SPL). The two sounds (the 1000-Hz reference and the test stimulus) are always presented in succession (never simultaneously) and sometimes to opposite ears if the listener has normal hearing. In a typical experiment, the method of adjustment is used where the listener adjusts the level of the test sound so that its loudness is equal to that of the reference sound. The level of the 1000-Hz tone in dB SPL is the loudness level of the test sound, measured in phons. — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 745 (#expands, via linked claim)

Loudness level of a sound is the sound pressure level of a I-kHz tone in a plane wave and frontal incident that is as loud as the sound; its unit is “phon”. — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1169 (#corroborates, via linked claim)

Categorization

• XREF: connects to: The phon unit anchors loudness to perceived equality across frequencies rather than raw SPL — Eric J. Heller, Why You Hear What You Hear- An…, 2002; Loudness is measured subjectively against 1 kHz reference tones — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1169; The phon scale defines loudness relative to equal-loudness matches at 1 kHz — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 745 (+3 more)

Related

• Loudness is measured subjectively against 1 kHz reference tones (similarity 0.96)
• The phon unit measures perceived loudness, not physical sound level (similarity 0.95)
• The phon scale defines loudness relative to equal-loudness matches at 1 kHz (similarity 0.94)
• The phon unit anchors loudness to perceived equality across frequencies rather than raw SPL (similarity 0.92)
• Loudness is measured by listeners assigning numbers relative to a reference sound. (similarity 0.92)
• The phon defines loudness level equal to dB SPL at 1 kHz (similarity 0.87)
• Equal-loudness-contour weighting schemes failed as loudness meters (similarity 0.87)
• Loudness depends on frequency, angle, duration, and envelope, not just level (similarity 0.86)
• Loudness, measured in sones, depends inherently on frequency content (similarity 0.86)
• Loudness is perceptual and unmeasurable directly, while intensity is acoustic and directly quantifiable (similarity 0.86)
• Loudness depends on more than physical sound intensity alone (similarity 0.86)
• Loudness scales with frequency squared, requiring large amplitude at low frequencies (similarity 0.86)
• Raising a sound’s loudness shifts its perceived pitch except near 1-2 kHz. (similarity 0.86)
• Loudness is measured psycho-acoustically via magnitude estimation against a reference (similarity 0.85)
• Stevens anchored the sone unit to a 1000-Hz tone at 40 dB SPL. (similarity 0.85)

Broader Connections

• The phon scale defines loudness relative to equal-loudness matches at 1 kHz #expands (1.00) — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 745
• Loudness is measured subjectively against 1 kHz reference tones #corroborates (0.95) — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1169
• The phon unit measures perceived loudness, not physical sound level #expands (0.90)