SOUND TRANSMISSION THROUGH THE COMBAT VEHICLE CREWMAN'S HELMET WHEN THE SEAL OF THE EARPADS IS BROKEN.

One of the basic functions of the Helmet, Combat Vehicle Crewmans, T-56-6, is to protect operating personnel against the high noise levels found in tanks and other armored vehicles. The noise suppression capability of this helmet, however, constitutes an impairment to the wearers ability to hear when worn outside such vehicles in comparatively quiet situations. Under the latter conditions, a means of permitting sounds to pass to the ears with minimum losses in intensity is required. It was the purpose of the study to determine how much improvement in sound reception would result if the seals between the CVC helmet earpieces and the wearers ears were broken. Author