What type of material was used for a ceramic mic element? Why was ceramic considered superior to crystal?
Barium titanate was the material commonly used for a ceramic mic element. (See U.S. Patent 2,640,165, issued May 26, 1953.) Lead Titanium Zirconate was also used.
For Shure microphones with ceramic elements, the ceramic material was obtained from Gulton Industries, Metuchen, New Jersey, or from Brush Electronics Company, Cleveland, Ohio.
A crystal mic element used a Rochelle salt crystal. This type of salt crystal could not withstand temperatures above 130 degrees F. Also direct moisture, or a very humid environment, would eventually damage the salt crystal. A ceramic element was far more tolerant of high temperature and high humidity. The advantages of the ceramic element eventually led to the elimination of the Rochelle salt crystal as a mic element.