NOISE ATTENUATION CHARACTERISTICS OF NINE PERSONNEL NOISE PROTECTIVE DEVICES.
Abstract
Nine noise protective devices were evaluated as to their noise attenuation characteristics using two generally different methods described in detail in Joint Project Report NM 001 064.01.16 and in Special Report 54-7 (Report No. 3 of TED PEN AE 1403). Physical measures were obtained from the output of a miniature condenser microphone serving as an 'artificial ear' shock-mounted within a plaster dummy head. The subjective measures were obtained from repeated observations of 9-17 trained listeners reporting on four listening tasks. These include (a) discrete frequency threshold shift, (b) noise and octave bands-of-noise threshold shift, (c) spondee word reception threshold shift, and (d) an 800 cps and spondee word shift to threshold from a 95 db level in the ear canal in a 116 db ambient HUP-2 noise. The results indicated that two of the devices yielded more attenuation to the frequencies 125,250, and 500 cps than has been found in evaluations of previous devices. Threshold judgments of listeners wearing the V51-R ear warden varied widely from individual to individual within the listening panel and in test-retest situation on the same observers. This variability apparently was not related to possible changes in the equipment used for stimuli presentation nor to subject reliability. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 10, 1955
- Accession Number
- AD0622056
Entities
People
- Gilbert C. Tolhurst
Organizations
- Ohio State University