Decibel

The decibel (dB) is a unit of measurement used to express sound intensity or electrical signal strength. It is based on a decimal logarithm of the ratio of the measured value to a reference value. For example, the normal sound intensity of a human conversation is between 60 and 70 dB. An aircraft taking off nearby can reach noise levels of 120 dB or more, which is very loud. A 10 dB increase represents approximately a 10-fold increase in loudness or signal strength. For example, if a sound is 10 times louder than another, it will be perceived as being 2 times louder than the other, which corresponds to an increase of 3 dB. The decibel is often used to measure noise, but it is also used in other areas, such as measuring signal strength in radio or telecommunications, or even to measure the brightness of stars.