Sound level

The decibel (dB) is a way of measuring sound. Sounds of 80-90dB or more can damage hearing and it is dangerous for people to work in sound levels of more than 90dB. Sounds above 130 dB become painful, and people should wear hearing protectors with sounds of more than 140dB. A decibel level of more than 150dB can cause permanent deafness. It is defined as the difference between the pressure which is found within a sound wave and the pressure of the medium outside of itself within the same medium. The time and/ or space are usually averaged with the square of the deviation from the equilibrium pressure, and a square root of such average is taken to a root mean square value. An insignificant disparity which is found in the pressure in air at an audio frequency will be perceived as a deafening sound which can cause damage in hearing.