About decibels (dB)

The decibel (dB) is the unit used to compare sound levels.  The threshold of normal human hearing is assigned the value of 0 dB.  This is the lowest level of sound that a human with normal hearing is usually able to hear.
Below are examples of commonly heard sound sources, along with an estimate of the dB sound levels that they produce:

Firecracker - 150dB
Rock concert - 110dB
Personal stereo system at maximum volume - 105dB
Motorcycle - 95dB
Lawn mower - 90dB
Heavy city traffic - 85dB
Normal conversation - 60dB
Refrigerator humming - 40dB
Whispered voice - 30dB
Threshold of normal hearing - 0dB