Sound Pressure Levels

extracted from usher loudspeakers owner manual..

Sound Pressure Levels

What is the loudest music or noise we can listen to before it damages our ears?

The human ear is incredibly sensitive and can hear everything from near total silence to a gunshot. In terms of power, the sound of the gunshot is about 1,000,000,000,000 times more powerful than the smallest audible sound!

But both music and noise can cause hearing loss if it’s loud enough and lasts long enough. The decibel (abbreviated dB) is the unit of measurement for intensity of sound.

On the decibel scale, the smallest audible sound is 0dB. Decibels are measured logarithmically. Thus, 20dB is 10 times the intensity of 10dB, and 30dB is 100 times
as intense as 10dB.

Here are some common sounds and their decibel ratings:
0 dB The faintest sound the human ear can detect
30 dB Quiet library, whisper
40 dB Living room, refrigerator, bedroom (away from traffic)
50 dB Normal conversation, quiet office
60 dB Sewing machine, typewriter
70 dB Vacuum cleaner, hair dryer
80 dB Normal city traffic, bedside alarm clock
90 dB Lawnmower, truck traffic, subway, motorcycle
100 dB Garbage truck, chainsaw, pneumatic drill
120 dB Loud rock concert, thunderbolt
140 dB Gunshot, firecracker, jet engine
180 dB Rocket launch

All these ratings were taken near the sound. Distance affects the intensity of sound —
if you are far away, the power is greatly diminished

hope you find this useful...sk