The floating mass transducer as a microphone-a pilot study

This study investigates the inverse use of the Vibrant Soundbridge® Floating Mass Transducer (FMT; MED-EL, Innsbruck, Austria) as a microphone in a pilot test. Should this be applicable, it would open up interesting application possibilities, e.g., as a microphone for a fully implantable cochlear implant.

Experimental measurements on an ear canal-eardrum model were used to analyze the acoustic properties of the FMT when used as a microphone, including frequency response and sensitivity. The FMT from the Direct Drive Simulation Set was coupled to the artificial eardrum for this purpose.

The results show that the FMT has a usable signal-to-noise performance over the entire frequency range investigated, albeit with a non-linear frequency characteristic. The highest sensitivity was found between 1500 and 2000 Hz.

The study suggests that an FMT optimized for microphone properties could be used as a microphone in the middle ear, which would open up new possibilities for the development of fully implantable hearing systems. Further investigations, in particular measurements on the petrous bone, are required to determine the suitability of the FMT as a middle ear microphone more precisely.