How is loudness measured? What is a dB?

How is loudness measured? What is a dB?

The unit of measurement used to express the intensity of a sound is the decibel (dB). The intensity of sound and the duration of exposure to the sound contribute to the overall sound energy level to which an individual is exposed. An individual’s risk of losing their hearing depends on how loud, for how long and how often they are exposed to loud sounds. Some common sounds and their intensities (dB) are indicated below.

Device/situation

dB (approximate)

Ticking watch

20

Soft whisper

30

Normal conversation

60

Vacuum cleaner

75

Heavy city traffic (inside the car)

85

Motorcycle

95

Hairdryer, subway train, car horn at 5 m

100

MP3 player at maximum volume, chainsaw

105

Shouting into the ear

110

Discotheques, bars and club

112

Loud rock concerts

115

Spectator trumpet 1 m from trumpet opening, sirens

120

Jackhammer, jet plane 30 m away

130

Firecrackers, firearms

150