This study investigated the effect on hearing, sound attenuation, and sound source identification of a prototype neck and two prototype mandible guards attached to a combat helmet. Ten male subjects participated. Free-field hearing thresholds were measured from 250 Hz to 8,000 Hz with the head bare and fitted with the helmet alone and with the guards. Sound source identification was assessed using a horizontal array of eight loudspeakers surrounding the subject. The stimulus was a 75-dB SPL, 300-ms noise burst. Neither the helmet worn alone or with the guards affected hearing or provided significant sound attenuation. The helmet combinations resulted in a significant decrease in sound source identification, of 11.6%. This was due to diminished accuracy for loudspeakers close to the interaural axis of the head. The neck guard induced a frontal bias for these positions. This error pattern is not likely to interfere with localization during combat.
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机译：这项研究调查了原型头盔和两个固定在战斗头盔上的下颌骨防护装置对听觉，声音衰减和声源识别的影响。十名男性受试者参加。裸露头部，单独戴头盔和戴防护装置时，在250 Hz至8,000 Hz范围内测量自由场听力阈值。使用围绕对象的八个扬声器的水平阵列评估声源识别。刺激因素是75 dB SPL，300 ms的噪声突发。头盔单独佩戴或与护卫人员都不会影响听力或提供明显的声音衰减。头盔组合导致声源识别效果显着下降11.6％。这是由于靠近头部耳轴的扬声器的准确性降低。护颈板在这些位置上引起正面偏斜。这种错误模式不太可能会干扰战斗中的定位。
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