Audio frequency
| Sound measurements | |
|---|---|
Characteristic |
Symbols |
| 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
- Absolute threshold of hearing
- Loudspeaker
- Musical acoustics
- Piano key frequencies
- Scientific pitch notation
- Whistle register
References
- ↑ Pilhofer, Michael (2007). Music Theory for Dummies. For Dummies. p. 97.
- ↑ "Hyperphysics". Retrieved 19 September 2014.
- ↑ Heffner, Henry; Heffner, Rickye (January 2007). "Hearing Ranges of Laboratory Animals". American Association for Laboratory Animal Science. 46 (1): 20. 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. PMID 12324385. doi:10.1093/bmb/63.1.73.