A-weighting is a standardized frequency-weighting characteristic that shapes a sound-level meter's response to approximate the human ear's sensitivity to low-level sounds: it attenuates frequencies far below and above the midrange, approximating the inverse of the 40-phon equal-loudness contour (ISO 226), normalized to 0 dB at 1 kHz. Its parameters are the four second-order filter sections with corner frequencies fixed by IEC 61672-1 — 20.6, 107.7, 313.1, 1219.4 Hz — which give it the characteristic steep low-frequency roll-off and milder high-frequency attenuation. The persistence mechanism is the standard itself: the curve is fixed in IEC 61672 and ISO 1996-2, reissued with each revision of the sound-level-meter standard, and implemented in hardware and digital filter chains in meters and audio analyzers worldwide. [formal: pondus frequentiae alpha | substrate: mind | horizon: centuries | explicit: yes | epoch: 0.16]
Accepted ontology entry
a-weighting
A-weighting is a standardized frequency-weighting characteristic that shapes a sound-level meter's response to approximate the human ear's sensitivity to low-level sounds: it attenuates frequencies far below and above the midrange, approxi…
Definition
Why it is in scope
A human-made standardized frequency-weighting characteristic, fixed in international sound-metering standards (IEC 61672, ISO 1996-2) and implemented in sound-level meters and audio analyzers, built to persist as a named standard curve.
Names and aliases
- a-weightingen · CANONICAL
Relations from this entry
- cmsv8p1xe00225xhkcozgvppfINSTANCE_OF →
A-weighting is a specific standardized frequency-weighting characteristic (IEC 61672 A-curve). It is a particular instance of the broader class of frequency-weighting techniques that apply frequency-dependent weighting to reflect human hearing sensitivity.
- cmsthfps6014z13a4dzw2hmvcDERIVED_FROM →
a-weighting DERIVED_FROM psychoacoustics. The A-weighting curve is designed to match the human ear's frequency response (40-phon equal-loudness contour), which is a psychoacoustic measurement. Psychoacoustics (study of sound perception) existed first; a-weighting is a derived engineering application of psychoacoustic findings. Law 7: which came first?
- cmsps9i0v06eejlssqrjcqyviDEPENDS_ON →
a-weighting DEPENDS_ON signal-processing. The A-weighting curve requires signal processing for its measurement and application — it is applied via weighting filters in signal processing systems. Removal test: remove signal processing, and a-weighting loses its operational framework for measuring and applying frequency weightings.
Relations to this entry
No accepted relations in this direction.
Record identity
- Created
- Aug 16, 2026, 4:06 AM UTC
- Content hash
- 9bdee295548592be395170f98534cd7a5468d79ac1079ca82e830ed5a67c9ec9