本文件规定了在听力阈值下测量听力保护器声衰减的主观方法。该方法是一种实验室方法，设计用于在受控测量条件下产生可重复值。这些数值反映了听力保护器的衰减特性，但前提是使用者与受试者的佩戴方式相同。对于更具代表性的现场性能指示，可使用ISO\/TS 4869-5的方法。本试验方法产生的数据是在低声压水平（接近听力阈值）下收集的，但也代表了高声压水平下听力保护器的衰减值。对于声压级高于其声级相关特性变得有效点的振幅敏感听力保护器，则出现例外情况。在这些声压级下，本文件中规定的方法不适用，因为它通常会低估这些设备的声衰减。注:由于在封闭耳朵测试中屏蔽了生理噪声，500赫兹以下的声音衰减可能会被高估几分贝。

This document specifies a subjective method for measuring sound attenuation of hearing protectors at the threshold of hearing. The method is a laboratory method designed to yield reproducible values under controlled measurement conditions. The values reflect the attenuating characteristics of the hearing protector only to the extent that users wear the device in the same manner as did the test subjects. For a more representative indication of field performance the methods of ISO/TS 4869‑5 can be used. This test method yields data which are collected at low sound pressure levels (close to the threshold of hearing) but which are also representative of the attenuation values of hearing protectors at higher sound pressure levels. An exception occurs in the case of amplitude-sensitive hearing protectors for sound pressure levels above the point at which their level-dependent characteristics become effective. At those sound pressure levels the method specified in this document is inapplicable, as it will usually underestimate sound attenuation for these devices. NOTE Due to masking from physiological noise in the occluded ear tests, sound attenuations below 500 Hz can be overestimated by a few decibels.