Comparison of Acoustic Properties of Two USMC Helmets

Abstract : The United States Marine Corps (USMC) has recently replaced an older Combat Vehicle Crewman (CVC) communications headset (the MK1697/G) with a newer version (Enhanced CVC headset [ECVCH]) manufactured by the same company (Sonetronics). A communications headset consists of two earphones and a microphone with the capability to receive and transmit communications across a radio or intercom. The ECVCH headset provides improvements in situational awareness through the addition of a talk-through microphone, in hearing protection through thicker ear pads, and in greater field ruggedness. A set of evaluations was conducted to determine if the ECVCH showed improvements in attenuation and speech intelligibility over the MK1697/G headset. There was no improvement in sound attenuation with the ECVCH. The ECVCH showed a decrement in speech intelligibility, although this decrement was not large enough to impact operational performance. The difference in performance can be explained by the differences in frequency responses between the two headsets.