DOI: 10.1121/10.0023765 ISSN: 0001-4966

A new method for measurement of impulsive peak level attenuation of hearing protectors

Cameron Fackler, Dan Gauger, Jeff G. Schmitt, William Murphy, Elliott Berger
  • Acoustics and Ultrasonics
  • Arts and Humanities (miscellaneous)

ASA/ANSI S12.42-2010 contains the first standardized test method for measuring the performance of hearing protection devices (HPDs) with high-level impulsive noise. This standard defines the impulsive peak insertion loss (IPIL) as a time-domain metric that quantifies the reduction in peak sound pressure level provided by an HPD for impulsive noises. However, IPIL as defined in S12.42-2010 is dependent on the spectrum of the impulsive noise source used for measurements of HPDs. Recent studies of HPDs with impulsive noise have led to the investigation of frequency-domain metrics and calculation methods. Using frequency-domain calculations allows the impulsive peak level attenuation to be computed for a wide range of impulsive noises, not only those used for the measurement. Consequently, significant revisions to S12.42 are under consideration and a new standard, ISO 4869-7, is being developed in parallel with the ANSI revision. This presentation highlights key proposals and substantive changes including: measurement and calculation of the frequency-dependent impulsive insertion loss (IIL), incorporation of frequency-domain aspects such as real-ear attenuation at threshold (REAT) limits to attenuation, and a new impulsive peak level attenuation metric (IPLA) to be calculated from the REAT-bounded IIL.

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