Psychophysical uncertainty estimates for real ear attenuation at threshold measurements in na´ve subjects.
Murphy-WJ; Byrne-D; Witt-B; Duran-J
NOISE-CON 2005: Proceedings of the 2005 National Conference on Noise Control Engineering, Minneapolis, Minnesota, October 17-19, 2005. Ames, IA: Institute of Noise Control Engineering of the USA, 2005 Oct; 1:558-565
The International Standards Organization (ISO) TC43 SC1 has directed the working groups to use the "Guide to the expression of Uncertainty in Measurement" (GUM) in the development of new acoustical standards. In light of this resolution, Working Group 17 on hearing protection has added an annex to a proposed standard ISO4869-7 describing a subject fit method for estimation of noise reduction. Data from two laboratories, NIOSH Pittsburgh Research Lab and Howard Leight Industries were analyzed to examine the within-test variance and between-test variance when subjects were tested using a Bekesy tracking paradigm. The NIOSH data demonstrated that the within-test variance, calculated from the reversals of the Bekesy tracks did not agree with the between-test variability of the subjects' repeated measures. This result prompted a revision of the testing software to determine the within-test variance from the midpoint of the Bekesy tracks. The revised software has been installed at both NIOSH PRL and Howard Leight facilities. This paper will compare the within-test and between-test variances determined with reversal levels and the midpoints from these two labs. The variability has been modeled with a simulated subject and Monte Carlo techniques.
Noise; Noise-levels; Acoustics; Acoustical-measurements; Hearing-protection; Hearing-conservation; Exposure-levels; Testing-equipment
William Murphy, National Institute for Occupational Safety and Health, Hearing Loss Prevention Team, MS C-27, 4676 Columbia Parkway, Cincinnati, OH 45226-1998
NOISE-CON 2005: Proceedings of the 2005 National Conference on Noise Control Engineering, Minneapolis, Minnesota, October 17-19, 2005