Wavelength (Sound)

Wave is one complete cycle of sound vibration passing through a medium (such as air) from compression through rarefaction and back to compression again. The physical length of this cycle is termed the wavelength. Wavelengths in air vary from about 1&1/16" for a 20,000-cycle per sec. (see Frequency) sound, to approximately 56&1/2' for a 20-cycle per sec. sound -- the two approximate extremes of human hearing sensitivity. There are waves outside of this range, but generally, they cannot be heard by humans.