Abstract
The acoustic effect of four resonators on the output of a single hearing aid was measured on ten subjects. The purpose was to compare the effect of each of the resonators in a 2 cc (2 cm) coupler and in real ears. Two of the resonators were special carhook resonators and the other two were contained in the earmolds. The output of the hearing aid with a standard earhook earmold configuration was compared to the output of the hearing aid through each of four earmold—earhook configurations. One resonator was present in each of the nonstandard systems. Each of the four comparisons was made in (1) the real ears using a probe microphone in a sound-treated test booth and (2) in the coupler with the hearing aid placed in a sound-treated test box. Predictable, systematic differences were found between the 2 cc coupler measurements and the real-ear measurements. Therefore, a reliable transfer function for each resonator can be expected when 2 cc coupler specifications are used to fit resonators for specific hearing losses.
Key Words: