How loud is a Decibel?
A decibel 9DB is a logarithmic unit meaning that you can't add and subtract decibels like whole numbers.
How many decibels a particular item generates speaks to the loudness of that unit. So, an increase of 3dB is a doubling of the "loudness" of the sound, while an increase of 10 dB means that the sound is 10 times as loud. For example a generator that is 72dB is twice as loud as a generator that is 62dB.
Common Items Decibel Ratings from Encarta 2005
Threshold of hearing: 0 dB
Rustling Leaves: 10 dB
Average Whisper: 20 dB
Quiet Conversation: 20-50 dB
Hotel: 40-50 dB
Loud Conversation: 50-65 dB
Traffic on a Busy Street: 65-70 dB
Train: 65-90 dB
Factory Noise: 75-80 dB
Thunder: 90-100 dB
Jet Aircraft at Takeoff: 110-140 dB
Threshold of Pain: 130 dB
Space Rocket on Takeoff: 140-190 dB
2,500 Watt MultiQuip GA25H at 30 Feet: 70 dBA
6,000 Watt MultiQuip GA6HEA at 30 Feet: 76 dBA
36,000 Watt MQ Power DCA-45SSIU2 at 23 Feet: 66 dBA
36,000 Watt MQ Power DCA-45USI at 23 Feet: 57 dBA