Decible (dB)

Decibel (dBA) is an International Scale of Sound Levels.

Decibel (symbol dB) is unit of measure used originally to compare sound intensities. Nearly all audible sounds lie between 0 and about 140 dB, where 0 dB is the 'threshold of hearing. A whisper has a sound intensity of 20 dB and 140 dB (a jet aircraft taking off nearby) is the threshold of pain. An increase of 10 dB means that the noise perceived by a listener has roughly doubled in loudness. A car passing at 70 dB sounds twice as loud as one passing at 60 dB. The dB measurement is widely used throughout the world for determining approximate human reaction to noise.