Field Evaluation of an Improved Ear Plug (INM-Modified V.51R),

Abstract : A modified form of the V.51R type ear plug designed to allow much improved speech communication, while retaining the impulse noise attenuation of the original V.51R, is described with a brief account of the principles which led to its design. Details are then given of the practical trials in which the expected performance was confirmed; these included speech communication tests under controlled and field conditions, and evaluation of the protection against the noise of the self-loading rifle (SLR) and two heavy weapons by measurements of temporary threshold shift. (Author)