Audio frequency

[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.

Sound propagates as mechanical vibration waves of pressure and displacement, in air or other substances.

When speaking about the frequency (in singular) of a sound, it means the property that most determines its pitch.