An auditory prosthesis comprising an actuator for providing mechanical stimulation to a recipient. The auditory prosthesis comprises a measurement circuit for use in determining the resonance peak(s) of the actuator. In an embodiment, the measurement circuit measures the voltage drop across the actuator and/or current through the actuator during a frequency sweep of the operational frequencies of the actuator. These measured voltages and/or currents are then analyzed for discontinuities that are indicative of a resonance peak of the actuator. In another embodiment, rather than using a frequency sweep to measure voltages and/or currents across the actuator, the measurement circuit instead applies a voltage impulse to the actuator and then measure the voltage and/or current across the actuator for a period of time after application of the impulse. The measured voltages and/or currents are then analyzed to identify resonance peak(s) of the actuator.