Earphones in audiometry. Committee on Hearing, Bioacoustics, and Biomechanics. Commission on Behavioral and Social Sciences and Education. National Research Council Working Group.

The advantages and disadvantages of three types of earphones for audiometric testing are discussed. Supraaural earphones continue to be recommended for this purpose, in preference to circumaural and insert types.

A model for predicting hearing aid performance.

A major problem in selecting a hearing aid is the inability to determine quickly and accurately, from manufacturers' data, the output speech and noise levels over the frequency range of interest and for arbitrary positions of hearing aid controls. This study demonstrates the feasibility of developing a model for a commercial hearing aid and the implementation of the model on a small desktop computer. With the model, output speech and noise levels can be predicted quickly and easily for any combination of control positions, even with the aid driven to saturation. The electroacoustic measurements required for development of the model and the schematic and mathematical models for the aid are presented. The validity of the model is demonstrated by comparing measured values of hearing aid gain, output noise levels, output speech levels and maximum output levels, with corresponding data from the computer model.