The decibel measures sound pressure or electrical pressure (voltage) levels. It is a logarithmic unit that describes a ratio of two intensities, such as two different sound pressures, two different voltages, and so
A decibel (dB) is the unit used to measure how loud a sound is. It starts at 0 – almost total silence. A decibel scale isn’t linear however. Going from 50dB to 100dB is not twice as loud but 16 times as loud; and from 60dB to 30dB is not half as loud but one-eighth as loud. Sound becomes dangerous to our hearing when it reaches certain levels. Regular exposure for more than one minute to 110dB for instance, risks permanent hearing loss. And prolonged exposure to any noise at or above 85dB can cause gradual hearing loss.