NOISE ATTENUATION CHARACTERISTICS OF TWO OVER-THE-EAR TYPE PERSONNEL NOISE PROTECTIVE DEVICES.
Abstract
Two personnel noise protective devices manufactured by the David Clark Co. were evaluated as to their noisepure tone-speech attenuation characteristics. Two general measuring techniques were employed to determine the relative effectiveness of the device 'on' versus device 'off': (1) physical measures obtained from the output of a miniature condenser microphone serving as an artificial ear within a manikin plaster head, and (2) listener-observer judgments of threshold shift of three types of ambient sound stimuli occasioned by the protective devices, listening binaurally. The data indicate that the physical measures (artificial ear) show more attenuation for the V-51R than for the 400-9 and 400-9D, except at frequencies below 1000 cps, and more attenuation for all steady-state 120 db noises used. Conversely, the listener-observer judgment data indicate slightly higher numerical threshold shift values for the 400-9 and 400-9D, except for the frequencies below 250 cps and the octave-bands below 150 - 300 cps. The Clark devices gave increased attenuation of Spondee words over that afforded by the V-51R. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- May 16, 1956
- Accession Number
- AD0622061
Entities
People
- Gilbert C. Tolhurst
Organizations
- Ohio State University