Decibel (dB)

A logarithmic unit of measurement that expresses the power ratio of two signals (e.g. sound waves). The higher the decibels, the higher the noise output from a device.

A change of 1dB marks an audible increase, whilst an increase of 10db effectively doubles the volume. For example, a quiet whisper is approximately equal to 20 dB, a TV at a distance of 1 metre would be approximately 60 dB, whilst a jack hammer at the same distance would measure 100 dB.