Towards a vibroacoustic coupler for eardrum contact transducers
* Presenting author
Abstract:
Despite technological advancements of hearing aids, acceptance can still be improved. To make hearing aids more comfortable and effective, the direct excitation of the eardrum through a vibroacoustic transducer has been proposed. An advantage of direct excitation is a broadband frequency transmission with an open ear canal, which can improve comfort and sound quality compared to conventional hearing aids that excite the eardrum acoustically via a miniature loudspeaker. We present first work towards the development of a coupler that enables repeatable and robust testing of eardrum contact transducers on the bench. The measurement principle is based on a small volume enclosed by a flexible membrane to which the transducer is coupled. A vibratory excitation by the transducer causes pressure changes inside the volume that can be measured using a microphone, with a high sensitivity potentially down to the picometer regime. Furthermore, the mechanical impedance of the eardrum with the coupled middle ear can be emulated by modifying the membrane and adding additional mechanical loads. First results with a Vibrosonic eardrum contact transducer verify the functionality of the principle. We present a characterization of the vibroacoustic coupler prototype and compare the performance to previous methods for testing eardrum contact transducers.