Abstract: A method and system employing a feedback signal indicative of monitored motion of an electro-mechanical acoustic transducer to generate one or both of a control signal for driving the transducer at its natural resonance frequency, and a warning signal indicating that the transducer is not vibrating at a frequency within a selected frequency range. In preferred embodiments, the transducer is a voice coil loudspeaker mounted in or on a vehicle. In other preferred embodiments, the electro-mechanical transducer is driven by an initial electrical pulse followed by a sequence of electrical pulses. A feedback signal indicative of monitored motion of a moving portion of the transducer is generated. Each pulse (following the initial pulse) is applied at a time (determined by the feedback signal) so as to drive the transducer at its actual natural resonance frequency.