Measurement and characterization of army impulsive noise sources

Peak pressure levels in army noise environments range from 140- to 195-dB near soldiers firing energetic weapons and are all dangerous to unprotected ears. Blast reverberation in confined spaces and steady noise in armored vehicles is also hazardous, so complete assessment requires the widest possible measurement range. To accurately measure pressures in the free-field or under hearing protectors, microphone considerations include type, location, orientation, mounting, shape, and shielding from flash or mechanical shock. Blast-waves rise instantaneously and return to free-field ambient within 0.3–15 ms, while in enclosures this can increase to 100 ms, requiring wide bandwidth signal processing. In addition to hazard, acoustic detection and annoyance at greater distances from weapons involve propagation effects in the atmosphere and at the ground which alter the wave-shape.