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Sound Power Levels

Sound powers for the following equation in dBA units are referenced to a picowatt (10-12 W).

Sound Power Formula - RF Cafe

Where: W1, W2 = sound power in similar units of watts

The threshold of pain for the human ear is usually taken to be around 120 dBA.

The following table presents examples of some common noise sources.

sound source
sound power
sound power
level Lw
dB re 10−12 W
Rocket engine 1,000,000 W 180 dB
Turbojet engine 10,000 W 160 dB
Siren 1,000 W 150 dB
Heavy truck engine or
loudspeaker rock concert
100 W 140 dB
Machine gun 10 W 130 dB
Jackhammer 1 W 120 dB
Excavator, trumpet 0.3 W 115 dB
Chain saw 0.1 W 110 dB
Helicopter 0.01 W 100 dB
Loud speech, vivid children 0.001 W 90 dB
Usual talking, Typewriter 10−5 W 70 dB
Refrigerator 10−7 W 50 dB
(Auditory threshold at 2.8 m) 10-10 W 20 dB
(Auditory threshold at 28 cm) 10-12 W 0 dB