An implantable hearing prosthesis for a recipient patient is described. An implantable signal transducer includes one or more electromagnetic drive coils for receiving an electrical stimulation signal and a cylindrical transducer magnet arrangement including an inner disk magnet having a first magnetic field direction, and an outer annular magnet surrounding the inner rod magnet and having a second magnetic field direction opposite to the first magnetic field direction. Current flow through the one or more electromagnetic drive coils from the electrical stimulation signal creates a coil magnetic field that interacts with the magnetic fields of the transducer magnet arrangement to create vibration in the transducer magnet which is developed by the signal transducer as a mechanical stimulation signal for audio perception by the patient.