Abstract: An apparatus for driving a speaker that includes an audio element moved by drive signals applied to the speaker, the speaker having a resistance and a force factor, includes: (a) an amplifier generating drive signals and having an output coupled with the speaker and an input; and (b) a feedback circuit coupling the speaker with the input and including: (1) a monitor coupled with the speaker and generating indicating signals representing selected speaker signal parameters; and (2) a processor coupled with the monitor, with the input and with a signal source providing received signals. The processor combines the received signals with the indicating signals to generate a modified signal for use by the amplifier in generating drive signals. The modified signal includes at least one factor relating to velocity of the audio element. Efficiency of the speaker is improved by inversely varying the resistance and the force factor with respect to each other.

Abstract: The present invention provides for an electromechanical transducer for producing sound in response to an audio signal. The transducer has a generally rectangular enclosure, a diaphragm, a cylinder, a drive shaft, a lever means, and a motor means. The diaphragm is associated with the cylinder. The outer diameter of the diaphragm is substantially similar to the inside diameter of the cylinder. The diaphragm is slidably associated with the cylinder. The motor has the characteristic of rotating in response to the application of electric current from an audio source. The characteristic of rotating is limited to an arc having an angle of less than 180 degrees. Thus the motor can make only fractional rotations upon the application of electric current. A method for producing sound in response to an audio signal is also provided.