LTC Lorraine Babeu
Within in the last ten years there has been great interest by the US Army in level dependent earmuffs and earplugs such as the Combat Arms Earplug which was developed at the French-German Institute. Since the use of level dependent systems are relatively new to the military’s inventory of personal protective equipment, there has been little research done by the US Army to determine the effect of the systems on human performance. The purpose of the study is to determine the effect of level dependent hearing protection, when compared to traditional hearing protection, on the user’s ability to recognize sounds at various distances. Twenty-two subjects wore the following hearing protective devices. Two of the devices were the level dependent Combat Arms Earplug yellow side and the E-A-R 9000 noise muffs. The other two devices were non level dependent Combat Arms Earplug green side and E-A-R 3000 noise muffs. They were asked to identify sounds presented at 50-300 meters from their position in an open field.