The level of sounds is measured as the intensity of a sound in the air at a listener's location.
The unit is decibels (dB).
On the decibel scale, the smallest audible sound (the threshold of hearing) is 0 dB.
• A sound 10 times more powerful is 10 dB. • A sound 100 times more powerful than near total silence is 20 dB. • A sound 1,000 times more powerful than near total silence is 30 dB