Harvey Fletcher
(1884-1981)
physicist

As a graduate student, he worked with Millikan and together they were the first to measure the charge on an electron. Millikan won the noble prize for that work. Fletcher directed research at Bell Labs where he played a central role in the development of stereophonic reproduction. He is also credited with inventing the hearing aid and the first audiometer. He was elected president of the American Physical Society in 1945.
Source: Famous LDS Scientists