Macrae J H, Dillon H
National Acoustic Laboratories, Chatswood NSW, Australia.
J Rehabil Res Dev. 1996 Oct;33(4):355-62.
The purpose of this project was to establish a maximum acceptable equivalent input noise level (EINL) for hearing aids. It was found that, if the version of the National Acoustic Laboratories (NAL) procedure for selecting the gain and frequency response of hearing aids, which includes modifications for severe and profound hearing loss is used, the EINL criterion can be relaxed for higher gain hearing aids, as a function of the gain of the aid. The relationship between relaxation of the criterion and 2-cc coupler gain is nonlinear, in different amounts, at the various frequencies, so no simple rule can be used to describe the manner in which the criterion can be relaxed.
本项目的目的是为助听器确定一个最大可接受等效输入噪声水平（EINL）。研究发现，如果使用国家声学实验室（NAL）选择助听器增益和频率响应的程序版本，其中包括针对重度和极重度听力损失的修正，那么对于增益较高的助听器，EINL标准可以放宽，这是助听器增益的一个函数。在不同频率下，标准放宽与2立方厘米耦合器增益之间的关系是非线性的，且程度不同，因此无法用简单规则来描述放宽标准的方式。
