Verification that the Naval Submarine Medical Research Laboratory Facility Meets ANSI Standards for Measuring the Effect of Hearing Protection on Horizontal Localization Performance (per ASA/ANSI S3.71-2019 Method 2)

The Naval Submarine Medical Research Laboratory (NSMRL) created a test facility in an anechoic room in accordance with Method 2 of the Acoustical Society of America (ASA) and the American National Standards Institute (ANSI) standard S3.71-2019 Methods for Measuring the Effect of Head-worn Devices on Directional Sound Localization in the Horizontal Plane (except where noted in Procedures). The mean open-ear (baseline) performance must be less than or equal to 10 degrees average error in order for a facility to make measures in accordance with Method 2. The results from this effort indicate that test facility at NSMRL is qualified to measure the effect of head-worn devices on horizontal localization ability. The Naval Submarine Medical Research Laboratory (NSMRL) created a test facility in an anechoic room, in accordance with Method 2 of the Acoustical Society of America (ASA) and the American National Standards Institute (ANSI) standard S3.71-2019 Methods for Measuring the Effect of Head-worn Devices on Directional Sound Localization in the Horizontal Plane (except where noted in Procedures). The aim of Method 2 is to measure the effect of headworn devices, including hearing protection devices, on an individuals ability to spatially localize sound in the horizontal plane. This effect is quantified in degrees of error from the correct sound location. This technical report describes the open-ear (baseline) performance used to certify the test facility designed and used at NSMRL. Facility performance was measured using 25 subjects whose hearing and vision were screened and found to be within normal limits. Subject performance screening was conducted with a deviation from ASA/ANSI S3.71-2019 (described herein). The results of this effort show a mean error of 6.9 degrees for the facility performance in the open-ear (baseline) condition for Method 2.