Quote:
Originally Posted by Sinbios
They only offer around 20-30dB of isolation, no? Normal traffic is like 60-70dB.
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Decibels are logarithmic, not linear, so........going from 40 dBA to 80dBA is going from a very silent room to outside on the street traffic. Going from 80 dB to 120 is going from standing in the middle of traffic to standing in front row in a rock concert or being close to a jet engine.
If you are sitting in the quietest possible room in your house, it will probably measure around 30 dBA.
Every 10 dB increase in noise means your perceived noise level has doubled. Try it on your own receiver on your stereo (most have a digital indicator that reads in decibels). If you go from -30 to -20, the music will sound twice as loud.
So if the earphone reduces noise by 10 dB, it will halve the noise level.
If it reduces noise by 20 dB, it will knock off 3/4 of the total noise level.
If it reduces noise by 30 dB, it will knock off 7/8 of the total noise level.
So if outside noise is 70 dB, and the earphone is rated at -30dB, you've stepped out of traffic into a very quiet room in your house.
30 dB reduction is a LOT. Remember, hearing protection devices (like earmuffs for shooting guns) are rated typically between 30 and 36 dB which is comparable to a good canalphone.