If the decibel scale is logarithmic, isn’t 33dB between 100 and 133 a much different amount in reality than 33dB is between 30dB & 63dB? So how can NRR 33 ear plugs reduce 60dB down to 30 while also reducing 140dB down to 110? Wouldn’t it only, say, reduce a 60dB noise by 33dB, but reduce a 140dB noise by a lesser amount? Does the ear plugs’ ability to reduce the sound increase with the volume?
If they really do subtract 33dB across the spectrum of dB ranges, then why are sub-33dB sounds still audible? Shouldn’t sounds around that range be effectively 0dB and inaudible?
If 60dB sounds are, say, 45dB with NRR33 earplugs, then are 100dB sounds actually 85 instead of 67? Or is there some mechanism enabling sounds that should be lowered to sub-40dB to be above 40, while also lowering 130dB to 100?
In: Physics
Part of the reason that you can still hear quiet sounds while wearing earplugs is that earplugs only block sound waves from coming into your ear directly through the air. Just like you’ll still hear any vibrations that can travel through the earplug, you’ll also hear a lot of vibrations that travel through your body. This is the idea behind how bone-conduction headphones work. Also we’re mostly made of water, so it’s easy for a sound from the air to go into the body, much easier than the other way around.
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