Abstract: Membranes for use with capacitive electric musical instrument vibration transducers comprise an acoustically vibrating surface, a vibrating variable capacitor plate made from an electrically conductive material, and means of electrically connecting said vibrating variable capacitor plate to the electric circuitry of a capacitive electric musical instrument vibration transducer. These membranes can be used as drumheads, banjo membranes, and other stretched vibrating surfaces on similar musical instruments. In addition to generating the sound associated with these instruments, these membranes help capacitive electric musical instrument vibration transducers generate a signal describing the emitted sound of the musical instruments they are attached to.

Abstract: A capacitive electric musical instrument vibration transducer contains one or more parallel plate variable capacitors. Each variable capacitor contains one vibrating variable capacitor plate, an electrically conducting surface that comprises, covers, or is embedded within an acoustically emitting vibrating surface on a musical instrument (such as a drumhead or soundboard), and one fixed variable capacitor plate comprising a rigid electrically conducting surface held a fixed distance away. When the instrument is played, the vibrating surface causes vibrations directly (without using airborne sound as an intermediary) in the vibrating variable capacitor plates, thus causing time-varying voltage oscillations in the parallel plate variable capacitors reflecting the vibrational state, and therefore the sound, of the instrument. An electric circuit in the transducer converts these voltage oscillations into the same kinds of signals produced by microphones and magnetic pickups.