Progress on a rating system for hearing protector attenuation.
J Acoust Soc Am 1999 Oct; 106(4):2262
The cumulative distribution of A-weighted noise reduction (CDNRA) has been proposed as an alternative to the noise reduction rating for hearing protectors [W. J. Murphy and J. R. Franks, J. Acoust. Soc. Am. 105, 1131 (1999)]. Individuals' REAT data were A-weighted and summed across frequencies to determine the statistical distribution. The cumulative distribution of REAT data was fit to a combination of two logistic curves to capture the features of well-fit and poorly-fit hearing protectors. Previously, the CDNRA model was shown to yield Pearson's correlation coefficients of 0.99 or better. In this paper, the CDNRA theory will be reviewed and the method will be applied to the subject-fit data from six HPDs. The Bilsom UF-1 earmuff was rated at 23-dB attenuation. The V-51R was rated at 6-dB attenuation. The EP100 was rated at 7-dB attenuation. And the EAR Classic was rated at 23-dB attenuation. Subject-fit data from the EAR Express and Howard Leight Max earplugs will be presented as well.
Hearing-level; Hearing-loss; Hearing-acuity; Health-surveys; Age-factors; Age-groups; Information-retrieval-systems; Physical-examination; Racial-factors; Sex-factors; Audiological-testing; Audiometry
William J. Murphy, Bioacoustics and Occupational Vibration Section, NIOSH, MS C-27, 4676 Columbia Pkwy., Cincinnati, OH 45226-1998
Journal of the Acoustical Society of America