The loudness of sound is measured in units called decibels, abbreviated "dB". A decibel unit expresses the relative intensity of sounds on a scale from zero for the average least perceptible sound to about 100 dB, which is near the level most people find uncomfortably loud. Normal speech is around 60 to 65 dB. When an individual is over-exposed to excessive sound levels, sensitive structures of the inner ear can be damaged, causing noise-induced hearing loss (NIHL).

Decibels of Sound: