Not sure about your numbers, 170 dB?

The noise level at a 25 m distance from a turbine engine of an airplane is only 140 dB (the highest noise level common people can be exposed to).   For workers to work in very noisy condition, the standard is set as 90 dB for 8 hours.  The sound pressure level (SPL) is an indicator and is expressed as log function of the sound power.  Most commonly, an increase of every 5 dB in SPL, the sound power is doubled.  For example, when the average noise level is increase to 95 dB, then a person can only work for 4 hours, 100 dB for 2 hours, 110 dB for 30 min, 120 dB 7.5 min. For a 170 dB noise level detectable even on the exterior surface of the subthe noise level inside the sub should be much higher.  How the soliders survive in the subs? 

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• 这大概和0dB的定义标准有关吧。我们平常所说的音量是相对于人耳能听到的最小音强 -大鱼翅- ♂ (138 bytes) () 04/09/2013 postreply 15:14:41