FREE FIELD THRESHOLD SHIFT AND TEMPORARY THRESHOLD SHIFT REDUCTION AS MEASURES OF EFFICIENCY OF EAR PROTECTIVE DEVICES

Abstract

The protective (attenuation) characteristics of two insert and one helmet ear protective device using the free field threshold shift (FFTS) and temporary threshold shift reduction (TTSR) techniques were evaluated with both impulse and continuous noise exposure. All devices tested were shown significantly to reduce TTS from impulseAND CONTINUOUS NOISE EXPOSURE. The insert devices were more effective at low frequencies, approximately equal to the helmet at high frequencies. It is believed the TTSR technique adds important information regarding the operational efficiency of the ear protectors tested. Because of special problems associated with helmets, it seems particularly desirable to include the TTSR technique in their evaluation. The data suggest that susceptibility to TTS from continuous exposure is not significantly correlated with that from impulse exposure. (Author)

Document Details

Document Type
Technical Report
Publication Date
May 28, 1962
Accession Number
AD0283276

Entities

People

  • John L. Fletcher
  • Michael Loeb

Organizations

  • United States Army Medical Research Laboratory

Tags

DTIC Thesaurus Topics

  • Attenuation
  • Efficiency
  • Free Field
  • Frequency
  • Frequency Bands
  • Test And Evaluation

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