An implantable microphone is described for use in hearing prosthesis systems. A cylindrical microphone housing has opposing circular cylinder ends and an interior volume containing an incompressible housing liquid. At least one housing membrane is on one of the cylinder ends and is in contact with the housing liquid and moveable in response to an acoustic signal outside the housing. An acoustic-electric transducer is coupled to the housing membrane for converting movement of the housing membrane into a corresponding electrical microphone signal.
