Audio frequency

An audio frequency (abbreviation: AF) or audible frequency is a periodic vibration whose frequency is in the band 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. An audio frequency (abbreviation: AF) or audible frequency is a periodic vibration whose frequency is in the band 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. The generally accepted standard range of audible frequencies for humans is 20 to 20,000 Hz, although the range of frequencies individuals hear is greatly influenced by environmental factors. In air at atmospheric pressure, these represent sound waves with wavelengths of 17 meters (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.