Phon
1. Phon is an unit of loudness level.
2. The phon is a logarithmic unit of loudness level for tones and complex sounds.
A unit of loudness that measures the intensity of a sound by the number of
decibels it is above a reference tone having a frequency of 1000 hertz and a root-
mean-square sound pressure of 20 × 10 –6 pascal.
The standard unit of loudness level, ranging upwards from zero for the faintest
audible sound. The loudness in phons of a sound is defined as the intensity level in
units of decibel sound pressure level (dB SPL) of a comparison pure tone of 1,000
hertz that is judged by the listener to be equally loud. Thus if the comparison tone is
20-dB SPL, then the loudness of any tone of another frequency that is judged to be
equally loud is defined as 20 phons; if the comparison tone is 40-dB SPL, then any
tone judged equally loud is 40 phons, and so on. See also equal-loudness contour.
From Greek phone sound or voice.
The loudness level of a sound is a subjective, rather than an objective, measure.
To measure loudness, the volume of a 1,000-hertz reference tone is adjusted
until it is perceived by listeners to be equally as loud as the sound being measured.
The loudness level, in phons, of the measured sound is then equal to the sound-
pressure level, in decibels, of the adjusted reference sound above the standard
reference level, which is the minimum audible threshold. A variation of one phon in
the loudness level of a sound is approximately the slightest change in sound-pressure
level detectable by the human ear under normal listening conditions
Phon. Oxford Reference. Retrieved from: https://www.oxfordreference.com/display/10.1093/oi/authority.20110803100323708; jsessionid=608D39846C8A97E6F74366A70400DDDE
Phon definition and meaning. Collins Online Dictionary. Retrieved from: https://www.collinsdictionary.com/dictionary/english/phon
Phon unit of measurement. Encyclopedia Britannica. Retrieved from: https://www.britannica.com/science/phon