HEARING PROTECTION PERFORMANCE EVALUATION OF ACTIVE NOISE REDUCTION HEADSETS UNDER HIGH INTENSITY NOISE LEVELS

摘要

The present study focuses on assessing the performance of hearing protectors with Active Noise Reduction (ANR) systems at the limit of their capabilities. The concern addressed in this study was raised following the noise survey onboard the CH-147 Chinook helicopter when an unweighted OSPL of 132 dB was recorded by NRC during the "Open Doors Level 140 kts" flight segment at four different locations in the cabin and the cockpit. Previous performance evaluation by NRC of David Clark headsets with ANR systems at an OSPL (Overall Sound Pressure Level) of 110dB in accordance with Standard Testing Procedure ANSI S12.42 resulted in positive recommendations based on their performance.