Variable pattern microphone system

Abstract

A microphone system including a plurality of sound transducers integrally contained in a single microphone housing, wherein each transducer has a different polar pick-up pattern. The system includes a remote combiner for the symmetrical addition of the output of each transducer into a composite signal of variable pattern. In the illustrated implementation, the system includes an electret microphone capsule having an omnidirectional pick-up pattern, an electret microphone capsule having a cardioid pick-up pattern, and an electret microphone capsule having a hypercardioid pick-up pattern. The capsules each have a mechanical acoustic phase shifting element to produce the desired pick-up patterns and are time aligned in the housing by placing the capsules together at the same location while pointing in the same direction. Each capsule has an independent power supply module and adjustable gain amplifier for the acoustical balancing of the system which is also integrally contained in the microphone housing. The combiner is shown implemented as a resistive switching network allowing the selection of multiple patterns, and alternatively, as a number of rheostats connected at a common node thereby providing an infinitely variable selection of patterns.