Sound measurements
 Sound pressure p, SPL,LPA
 Particle velocity v, SVL
 Particle displacement δ
 Sound intensity I, SIL
 Sound power P, SWL, LWA
 Sound energy W
 Sound energy density w
 Sound exposure E, SEL
 Acoustic impedance Z
 Audio frequency AF
 Transmission loss TL

An audio frequency or audible frequency (AF) is a periodic vibration whose frequency is in the band audible to the average human, the human hearing range. The SI unit of frequency is the hertz (Hz). It is the property of sound that most determines pitch.[1]

The generally accepted standard hearing range for humans is 20 to 20,000 Hz.[2][3][4] In air at atmospheric pressure, these represent sound waves with wavelengths of 17 metres (56 ft) to 1.7 centimetres (0.67 in). Frequencies below 20 Hz are generally felt rather than heard, assuming the amplitude of the vibration is great enough. High frequencies are the first to be affected by hearing loss due to age or prolonged exposure to very loud noises.[5][failed verification]

Frequencies and descriptions

Frequency (Hz) Octave Description
16 to 32 1st The lower human threshold of hearing, and the lowest pedal notes of a pipe organ.
32 to 512 2nd to 5th Rhythm frequencies, where the lower and upper bass notes lie.
512 to 2,048 6th to 7th Defines human speech intelligibility, gives a horn-like or tinny quality to sound.
2,048 to 8,192 8th to 9th Gives presence to speech, where labial and fricative sounds lie.
8,192 to 16,384 10th Brilliance, the sounds of bells and the ringing of cymbals and sibilance in speech.
16,384 to 32,768 11th Beyond brilliance, nebulous sounds approaching and just passing the upper human threshold of hearing
MIDI note Frequency (Hz) Description Sound file
0 8.17578125 Lowest organ note n/a (fundamental frequency inaudible)
12 16.3515625 Lowest note for tuba, large pipe organs, Bösendorfer Imperial grand piano n/a (fundamental frequency inaudible under average conditions)
24 32.703125 Lowest C on a standard 88-key piano.
36 65.40625 Lowest note for cello
48 130.8125 Lowest note for viola, mandola
60 261.625 Middle C
72 523.25 C in middle of treble clef
84 1,046.5 Approximately the highest note reproducible by the average female human voice.
96 2,093 Highest note for a flute.
108 4,186 Highest note on a standard 88-key piano.
120 8,372
132 16,744 Approximately the tone that a typical CRT television emits while running.

See also


  1. ^ Pilhofer, Michael (2007). Music Theory for Dummies. For Dummies. p. 97. ISBN 9780470167946.
  2. ^ "Hyperphysics". Retrieved 19 September 2014.
  3. ^ Heffner, Henry; Heffner, Rickye (January 2007). "Hearing Ranges of Laboratory Animals". Journal of the American Association for Laboratory Animal Science. 46 (1): 20–2. PMID 17203911. Retrieved 19 September 2014.
  4. ^ Rosen, Stuart (2011). Signals and Systems for Speech and Hearing (2nd ed.). BRILL. p. 163. For auditory signals and human listeners, the accepted range is 20Hz to 20kHz, the limits of human hearing
  5. ^ Bitner-Glindzicz, M (2002). "Hereditary deafness and phenotyping in humans". British Medical Bulletin. 63 (1): 73–94. doi:10.1093/bmb/63.1.73. PMID 12324385. S2CID 3548932.