Alternative Field Methods for Measuring Hearing Protector Performance

In comparison with the mandatory noise reduction rating (NRR) testing of every hearing protector sold in the United States, real-world tests of hearing protector attenuation are scarce. This study evaluated data from three potential field-test methods as compared with the subject-fit data from Method B of ANSI S12.6-1997 for the E·A·R® Express™ Pod Plug™. The new field-test methods were the FitCheck headphone (FCH) method, FitCheck in sound field (FCSF) method, and bone-conduction loudness balance (BCLB) method, all of which can be administered in small single-person audiometric booths such as are commonly found in industry. Twenty normal-hearing and audiometrically competent subjects naive to hearing protector use were tested with the laboratory and the three field-test methods in a repeated-measures design. Repeated-measures models with structured covariance matrices were used to analyze the data. Significant effects were found for method, frequency, and first-order frequency-by-gender and frequency-by-...