Phon 215441 224892185 2008-07-10T21:40:01Z DocWatson42 38455 Performed clean up. The '''phon''' was proposed as a [[physical unit|unit]] of [[perception|perceived]] [[loudness]] [[level]] ''L''<sub>N</sub> for pure tones<ref>[http://www.phys.unsw.edu.au/~jw/dB.html#log UNSW Music Acoustics<!-- Bot generated title -->]</ref> by [[S. S. Stevens]]. The purpose of the phon scale is to compensate for the effect of frequency on the perceived loudness of tones.<ref>William M. Hartmann, ''Signals, Sound, and Sensation'', American Institute of Physics, 2004. ISBN 1563962837.</ref> By definition, 1 phon is equal to 1 [[sound pressure level|dBSPL]] at a frequency of 1 [[kHz]].<ref>[http://hyperphysics.phy-astr.gsu.edu/hbase/sound/phon.html Loudness Units: Phons and Sones], HyperPhysics, by C. R. Nave. Accessed [[10 July]] [[2008]].</ref> The [[equal-loudness contour]]s are a way of mapping the dBSPL of a pure tone to the perceived loudness level in phons. These are now defined in the international standard ISO 226:2003, and it should be noted that the research on which this document is based concluded that earlier [[Fletcher–Munson curves]] and [[Robinson-Dadson curves]] were in error. Although proposed as units, phons are not generally accepted according to the stringent criteria of [[metrology]], and have not been accepted as standard units by the United States [[National Institute of Standards and Technology]]. The phon model can be extended with a time-varying transient model which accounts for "turn-on" (initial transient) and long-term, [[listener fatigue]] effects. This time-varying behavior is the result of [[psychology|psychological]] and [[physiology|physiological]] audio processing. The equal-loudness contours on which the phon is based apply only to the perception of pure steady tones; tests using octave or third-octave bands of noise reveal a different set of curves, owing to the way in which the [[critical band]]s of our hearing integrate power over varying bandwidths and our brain sums the various critical bands. ==See also== *[[Sone]] *[[A-weighting]] ==References== {{reflist}} *[http://ccrma.stanford.edu/~jos/TimeFreqDisplay/Sones_Phons.html Explanation] with definitions [[Category:Hearing]] [[Category:Units of measure]] [[Category:Human-based units of measure]] [[Category:Acoustics]] [[bg:Phon]] [[de:Phon (Einheit)]] [[es:Fonio]] [[it:Phon (psicoacustica)]] [[nl:Phon]] [[ja:ホン]] [[no:Phon]] [[pl:Fon (natężenie dźwięku)]] [[ru:Фон (акустика)]] [[sk:Fón]]