Source: pianonator – Dr. James E. West, formerly of Bell Laboratories, now research professor at Johns Hopkins University, interviewed on June 10, 2009, for the occasion of the Juneteenth celebration by the Student Technology Services, celebrating contributions to science and technology by African-American innovators. West, together with Gerhard Sesslar, invented the Electret Microphone, which is used in roughly 95 percent of microphone applications today.