Pekkarinen J O, Starck J P, Ylikoski J S
Institute of Occupational Health, Laajaniityntie 1, Vantaa, Finland.
J Acoust Soc Am. 1992 Jan;91(1):196-202. doi: 10.1121/1.402754.
The earmuff attenuation of acoustic impulses produced by large-caliber weapons was measured with a high-speed microcomputer controlled unit. The estimated accuracy was +/- 1 dB in peak sound-pressure level measurements. The peak levels outside earmuffs were 184 dB for the heavy bazooka and 172 dB for the hand-held bazooka (re: 20 microPa). Heavy bazooka impulse peak levels were attenuated from 7 to 19 dB by the earmuffs depending on the mass and volume of the measured three types of earmuffs. Hand-held bazooka impulse peak levels were attenuated by the earmuffs from 9 to 15 dB. The risk limits for hearing loss from a single impulse were exceeded in spite of the use of earmuffs when the criteria of CHABA (USA) or Pfander (Germany) were applied. The unexpectedly low attenuation was due to the low-frequency waveform of the high-level impulses. The earmuffs were found to prolong the impulse duration, which may reduce the benefit otherwise achieved by attenuation of the peak levels.
采用高速微机控制装置测量了大口径武器产生的声脉冲的耳罩衰减。在峰值声压级测量中，估计精度为±1dB。耳罩外的峰值水平，重型火箭筒为184dB，手持式火箭筒为172dB（参考值：20μPa）。根据所测三种耳罩的质量和体积，重型火箭筒的脉冲峰值水平被耳罩衰减了7至19dB。手持式火箭筒的脉冲峰值水平被耳罩衰减了9至15dB。当应用美国CHABA或德国Pfander的标准时，尽管使用了耳罩，但单次脉冲导致听力损失的风险限值仍被超过。意外的低衰减是由于高电平脉冲的低频波形。发现耳罩会延长脉冲持续时间，这可能会降低峰值水平衰减原本可带来的益处。
