n.
Unit for measuring the relative intensities of sounds or the relative amounts of acoustic or electric power.
Because it requires about a tenfold increase in power for a sound to register twice as loud to the human ear, a logarithmic scale is useful for comparing sound intensity. Thus, the threshold of human hearing (absolute silence) is assigned the value of 0 dB and each increase of 10 dB corresponds to a tenfold increase in intensity and a doubling in loudness. The "threshold of pain" for intensity varies from 120 to 130 dB among different individuals. A related unit is the bel = 10dB.