"Most efficient modern suppressors will drop the sound ofa gunshot by at least 30 dB.To appreciate how significant a reduction 30 dB represents,one needs to understand how sound is measured.The decibel scale is logarithmic, meaning that each unitis 10 times that of the preceding one. For example, a noisesource measuring 80 dB is 10 times as loud as a source measuring70 dB and 100 times as loud as a source reading of60 dB. A small difference in value actually means a tremendousdifference in intensity. So reducing a gunshot by even30 dB makes it 1,000 times quieter, and it is through this tremendousdrop in the amount of sound that the suppressorpreserves your hearing from damage." Taken from Tacticalmedicine.com