Loudness is the perceptual correlate of acoustic stimulus intensity — the subjective magnitude with which a listener experiences sound pressure. It is not identical to sound pressure level (SPL); rather, loudness is the mind's mapping of physical amplitude onto a psychological scale, governed by Stevens' power law (perceived magnitude ≈ k × stimulus^n, where n≈0.6 for loudness). Loudness depends on frequency (equal-loudness contours / Fletcher-Munson curves), duration (temporal integration), and spectral content. It persists through standardized psychophysical scaling (the sone scale, anchored at 40 phons = 1 sone) and engineering approximations (the phon scale, derived from equal-loudness contours relative to 1 kHz reference tones). These scales are codified in ISO 226 and used in audio engineering, acoustical architecture, and hearing-science research to predict and control how humans experience sound intensity. [formal: intensitas soni | substrate: mind | horizon: a moment | explicit: yes | epoch: 0.36]
Accepted ontology entry
loudness
Loudness is the perceptual correlate of acoustic stimulus intensity — the subjective magnitude with which a listener experiences sound pressure. It is not identical to sound pressure level (SPL); rather, loudness is the mind's mapping of p…
Definition
Why it is in scope
A human-made perceptual construct for quantifying the intensity of sound as experienced by a listener — the subjective magnitude of acoustic stimulus. Persisted through psychophysical scaling laws (Stevens' power law) and engineering metrics (phon, sone, dB SPL) that map physical amplitude to perceived intensity.
Names and aliases
- loudnessen · CANONICAL
Relations from this entry
- cmsorsyn802qbjlss3cb2ruiyDEPENDS_ON →
Loudness perception is fundamentally frequency-dependent: the same SPL at different frequencies produces different perceived loudness (equal-loudness contours). The concept of loudness as a perceptual construct cannot operate without frequency — the cochlea's frequency analysis and the definition of loudness units (phon, sone) are all frequency-relative.
- cmrrknru301u9q89dknhxr8xdDEPENDS_ON →
Loudness is a human-made perceptual construct for quantifying sound intensity. Remove perception and loudness as a perceptual magnitude loses its referent. The concept operates within the domain of subjective experience.
- cmsownpg6038bjlssx63pg9gcDEPENDS_ON →
Loudness is the perceptual magnitude of sound intensity, which is physically grounded in amplitude. Remove amplitude and loudness loses its physical referent — loudness IS the perception of amplitude variation. Object-level dependency: loudness operates by mapping amplitude to subjective intensity.
Relations to this entry
No accepted relations in this direction.
Record identity
- Created
- Aug 11, 2026, 4:35 PM UTC
- Content hash
- 502865bb0eb79f4d5e4515130d70e9204b45caae1576050f617c7667b8ff4ce7