In:
The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 120, No. 5_Supplement ( 2006-11-01), p. 3160-3160
Abstract:
As active noise reduction (ANR) becomes more common, the need has developed for the measurement of device attenuation, passive and active combined, for use in noise protection calculations. An experiment was conducted involving both REAT and MIRE measurements on five circumaural and two supra-aural ANR devices in two different laboratories. Subject selection and instruction were consistent with the ANSI S12.6-1997 Method B fitting paradigm for all measurements. MIRE was measured both using microphones mounted on canal-occluding plugs near the entrance of the canal (‘‘shallow MIRE’’) and using concha-mounted microphones with probe tubes extending near to the tympanic membrane and an unoccluded canal (‘‘deep MIRE’’); the latter measurements were done with the same device fitting trials as the REAT measurements. The two MIRE measurements were quite similar, with the shallow MIRE values typically better by margins of only 0.5 to 1.0 dB at all frequencies. A positive REAT minus MIRE difference at the lower frequencies consistent with the effects of physiological noise masking was observed. Various analyses of the data are presented and a recommendation is made for how ANR device total attenuation might be measured in a future standard as part of a hearing protector rating regime encompassing both passive and active devices.
Type of Medium:
Online Resource
ISSN:
0001-4966
,
1520-8524
Language:
English
Publisher:
Acoustical Society of America (ASA)
Publication Date:
2006
detail.hit.zdb_id:
1461063-2
