Wikipedia
Audio frequency
An audio frequency or audible frequency (AF) is a periodic vibration whose frequency is audible to the average human. The SI unit of frequency is the hertz (Hz). It is the property of sound that most determines pitch.[1]
| Sound measurements | |
|---|---|
Characteristic | Symbols |
| 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 |
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] Sound frequencies above 20 kHz are called ultrasonic.
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
- Absolute threshold of hearing
- Hypersonic effect, controversial claim for human perception above 20,000 Hz
- Loudspeaker
- Musical acoustics
- Piano key frequencies
- Scientific pitch notation
- Whistle register
References
- ^ Pilhofer, Michael (2007). Music Theory for Dummies. For Dummies. p. 97. ISBN 9780470167946.
- ^ "Hyperphysics". Retrieved 19 September 2014.
- ^ 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.
- ^ 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
- ^ 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.