Sound Power Levels
Sound powers for the following equation in dBA units are referenced to a picowatt (10-12 W).
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.
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.
| Situation and sound source | sound power Pac watts | 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 |