Audio frequency

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

An audio frequency (abbreviation: AF) or audible frequency is characterized as a periodic vibration whose frequency is audible to the average human. The SI unit of audio frequency is the hertz (Hz). It is the property of sound that most determines pitch.[1]

The generally accepted standard range of audible frequencies is 20 to 20,000 Hz,[2][3][4] although the range of frequencies individuals hear is greatly influenced by environmental factors. Frequencies below 20 Hz are generally felt rather than heard, assuming the amplitude of the vibration is great enough. Frequencies above 20,000 Hz can sometimes be sensed by young people. High frequencies are the first to be affected by hearing loss due to age and/or prolonged exposure to very loud noises.[5]

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 2048 6th to 7th Defines human speech intelligibility, gives a horn-like or tinny quality to sound.
2048 to 8192 8th to 9th Gives presence to speech, where labial and fricative sounds lie.
8192 to 16384 10th Brilliance, the sounds of bells and the ringing of cymbals and sibilance in speech.
16384 to 32768 11th Beyond Brilliance, nebulous sounds approaching and just passing the upper human threshold of hearing
MIDI Note Frequency (Hz) Description Sound File
C-1 8.18 Lowest organ note N/A (fundamental frequency inaudible)
C0 16.35 Lowest note for tuba, large pipe organs, Bösendorfer Imperial Grand Piano N/A (fundamental frequency inaudible under average conditions)
C1 32.70 Lowest C on a standard 88-key piano.
C2 65.41 Lowest note for cello
C3 130.81 Lowest note for viola, mandola
C4 261.63 Middle C
C5 523.25 C in middle of treble clef
C6 1046.50 Approximately the highest note reproducible by the average female human voice.
C7 2093 Highest note for a flute.
C8 4186 Highest note on a standard 88-key piano.
C9 8372
C10 16744 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.
  2. "Hyperphysics". Retrieved 19 September 2014.
  3. Heffner, Henry; Heffner, Rickye (January 2007). "Hearing Ranges of Laboratory Animals". American Association for Laboratory Animal Science. 46 (1): 20. 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.
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