How loud is my air conditioning unit: noise level explained and real world examples.
The decibel (abbreviated dB) is the unit used to measure the intensity of a sound. The decibel scale is a little odd because the human ear is incredibly sensitive. Your ears can hear everything from your fingertip brushing lightly over your skin to a loud jet engine which, in terms of power, the sound of the jet engine is about 1,000,000,000,000 times more powerful than the smallest audible sound. That's a big difference!
On the decibel scale, the smallest audible sound (near total silence) is 0 dB. It is worth noting that decibels (dB) are measured logarithmically therefore 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. Here are some common sounds and their decibel ratings:
· Near total silence - 0 dB
· Normal breathing – 10 dB
· A mosquito or rustling leaves - 20 dB
· Typical library / dripping tap / fridge – 40 dB
· Normal conversation / quiet office - 50 dB
· Laughter / bird sound – 60 dB
· Vacuum cleaner / hairdryer – 70 dB
· A lawnmower - 90 dB
· A car horn - 110 dB
· A rock concert or a jet engine - 120 dB
· A gunshot or firecracker - 140 dB
You know from your own experience that distance affects the intensity of sound -- if you are far away, the power is greatly diminished. All of the ratings above are taken while standing near the sound.
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