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Decibel levels

Posted: Mon Jun 25, 2012 11:26 pm
by binder
So I looked up decibel level comparison charts after researching can decibel reductions and I'm just not getting it. I've shot my can I'm waiting for Sam to allow me to take home and the decibel levels are what I believed to be more than safe but these comparison charts liken these decibel levels to, what I believe to be, MUCH louder noises. Is it the duration of the sound that is the problem or is even what I believe to be hearing safe still causing damage?

Re: Decibel levels

Posted: Tue Jun 26, 2012 3:37 am
by eracer
SPL (Sound Pressure Level) is what concerns us here.

The dB scale by which all sound is measured is logarithmic, and is referenced to the lower threshold of human hearing. A sound that is 10 times more intense (i.e. higher amplitude) is 10dB above that threshold. A sound that is 100 times more intense is 20dB above the threshold. And a sound that is 100,000 times as intense is 50dB above the threshold.

So when a silencer reduces the measured sound level by 30dB, it's reducing the sound pressure (amplitude) by a factor of 1,000.

That's why a 150dB impulsive sound like a gunshot can be immediately damaging and immediately painful, and one that measures 30dB less can be more easily tolerated.

The duration of exposure is a factor. Your hearing can be damaged by 8 hours of exposure to 90dB, but can tolerate 120dB for short periods.

Silencers, when used on small caliber weapons can reduce sound pressure levels enough to be considered 'hearing safe' but should only be tolerated for a short time. Keep in mind that perception affects us as well. We 'expect' a gunshot to be loud, and when a silencer is attached, the reduction in SPL leads us to believe that the sound is 'quieter' than it is.

Re: Decibel levels

Posted: Tue Jun 26, 2012 10:59 am
by binder
So.......are suppressors really hearing safe if they're in the 130-140db range? My blackout and .22 can "sound" hearing safe as a car door shutting is far louder.....but are they really or is it a case of personal perception becoming reality?