phon

phon   (fŏn)    n.  A unit of apparent loudness, equal in number to the intensity in decibels of a 1,000-hertz tone perceived to be as loud as the sound being measured. [German, from Greek phōnē, sound; see phone1.]

phono- 

Main Entry: phon
Pronunciation: 'fän
Function: noun
: the unit of loudness on a scale beginning at zero for the faintest audible sound and correspondingto the decibel scale of sound intensity with the number of phons of a given sound being equal to the decibels of a pure 1000-hertz tone judged by the average listener to be equal in loudness to thegiven sound

phon- pref.
Variant of phono-.

phon   (fŏn)  Pronunciation Key  A unit of apparent loudness. The loudness of a signal in phons is equal to the intensity in decibels of a 1,000-hertz tone judged to be as loud as the signal being measured.

phon

unit of loudness level. 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 smallest change in sound-pressure level detectable by the human ear under normal listening conditions

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