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Term: Decibel

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Term: Decibel


The decibel (dB) is a logarithmic unit of measurement that expresses the magnitude of a physical quantity (usually power or intensity) relative to a specified or implied reference level. A decibel is one tenth of a bel (B). Although the term applies to digital data in a general way, most usage in a digital library context pertains to sound. The decibel expresses a ratio of two quantities with the same unit and thus it is a dimensionless unit. Since the decibel (dB) is a logarithmic unit, an increase of 3 dB is a doubling of the strength of the sound, an increase of 10 dB means that the sound is 10 times as loud. Thus 70 dB is 10 times as loud as 60 dB.

The expression dB FS (or dbFS) means decibels relative to full scale.

Decibel (Wikipedia article)
See also:
Signal to noise ratio; Decibels relative to full scale