Text: abbreviated "db" is the standard measure of loudness. It is a relative measurement, used to compare two different loudness levels. For instance, if a loudspeaker is "5 db down at 40 cycles" (usually written "-5 db"), the sound it produces at a frequency of 40 cycles per second is 5 db softer than the sound it produces at a standard reference frequency - usually 1000 Hz. The smallest readily apparent loudness difference in music is 3 db, though sharp-eared listeners may discern differences as small as 1 db.

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