scope:

This standard covers the terminology, procedures and essential equipment characteristics for the measurement of the acoustic output and acoustic gain of hearing aids, coupled to human ears, in a variety of acoustic environments and for the measurement of certain acoustic properties of the ear related to the application of hearing aids. These measurements can be divided into two classes: a) direct measures of sound pressure level (SPL), and b) insertion measurements. Direct measures (previously called in situ measurements) report SPL developed in an ear canal, with or without a hearing aid in place and are expressed as dB gain relative to the SPL at a field reference point. Insertion measurements report ear canal SPL with a hearing aid in place relative to the ear canal SPL without the hearing aid. Behavioral measures of real-ear hearing aid performance, such as functional gain, are excluded from this standard.

Purpose

The purpose of this standard is to assist those making or interpreting the results of real-ear performance measurements of hearing aids by promoting consistency in terminology, procedures and equipment specification.