Minimum audibility curve is a standardized graph of the
threshold of hearing frequency for an average human, and is used as the reference level when measuring hearing loss with an
audiometer as shown on an
audiogram.
Audiograms are produced using a piece of test equipment called an
audiometer, and this allows different frequencies to be presented to the subject, usually over calibrated headphones, at any specified level. The levels are, however, not absolute, but
weighted
A weight function is a mathematical device used when performing a sum, integral, or average to give some elements more "weight" or influence on the result than other elements in the same set. The result of this application of a weight function is ...
with frequency relative to a standard graph known as the minimum audibility curve which is intended to represent 'normal' hearing. This is not the best threshold found for all subjects, under ideal test conditions, which is represented by around 0
phon
The phon is a logarithmic unit of loudness level for tones and complex sounds. Loudness is measured in sone which is a linear unit. Human sensitivity to sound is variable across different frequencies; therefore, although two different tones may ...
or the
threshold of hearing on the
equal-loudness contours, but is standardised in an
ANSI
The American National Standards Institute (ANSI ) is a private non-profit organization that oversees the development of voluntary consensus standards for products, services, processes, systems, and personnel in the United States. The organ ...
standard to a level somewhat higher at 1 kH
There are several definitions of the minimal audibility curve, defined in different international standards, and they differ significantly, giving rise to differences in audiograms according to the audiometer used. The ASA-1951 standard for example used a level of 16.5 dB SPL at 1 kHz whereas the later ANSI-1969/ISO-1963 standard uses 6.5 dB SPL, and it is common to allow a 10 dB correction for the older standard.
See also
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Articulation index
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Audiogram
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Audiology
Audiology (from Latin , "to hear"; and from Greek , '' -logia'') is a branch of science that studies hearing, balance, and related disorders. Audiologists treat those with hearing loss and proactively prevent related damage. By employing vario ...
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Audiometry
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A-weighting
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Equal-loudness contour
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Hearing range
Hearing range describes the range of frequencies that can be heard by humans or other animals, though it can also refer to the range of levels. The human range is commonly given as 20 to 20,000 Hz, although there is considerable variatio ...
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Hearing (sense)
Hearing, or auditory perception, is the ability to perceive sounds through an organ, such as an ear, by detecting vibrations as periodic changes in the pressure of a surrounding medium. The academic field concerned with hearing is audit ...
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Psychoacoustics
Psychoacoustics is the branch of psychophysics involving the scientific study of sound perception and audiology—how humans perceive various sounds. More specifically, it is the branch of science studying the psychological responses associated ...
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Pure tone audiometry
External links
''Hearing Loss'' by Robert Thayer Sataloff
{{DEFAULTSORT:Minimum Audibility Curve
Otology
Acoustics