Method and apparatus for driving a self-resonant acoustic transducer

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. Some embodiments monitor the peak velocity (rather than displacement) of a driven electro-mechanical transducer, process the monitored peak velocity signal to generate feedback indicative of actual radiated energy from the transducer, and generate from the feedback signal one or both of a control signal for driving the transducer in a desired manner and a warning signal indicating that the transducer has not radiated a selected minimum amount of energy.