H. J. L. Struycken was a Dutch otolaryngologist, phonetician, and acoustician. After studying medicine in Groningen, in 1893 he started working at the Voorburg psychiatric hospital near Vught, where he attempted to distinguish psychiatric conditions from neurological speech disorders. His interest in phonetics and acoustics took Struycken to France and Germany, to visit clinics and approach instrument makers who could produce tuning forks for him to use in his clinical research.

Picture: CC0 | Wikimedia

Georg von Békésy was a Hungarian-American biophysicist who worked on physiology of hearing.

After studying chemistry in Bern, in 1923 Békésy was awarded a PhD in physics at the University of Budapest. He entered the service of the Hungarian Post Office, where he worked at the research laboratory on problems of long-distance telephone transmission.

Hallowell Davis was born on August 31, 1896, in New York City and died on August 22, 1992, in St. Louis, Missouri. He was a physiologist and otolaryngologist, and his research contributed to the development of electroencephalography (EEG). Davis was also a pioneer in the physiology of hearing, the inner ear, and the auditory nerve’s electrical responses.

Hermann Ludwig Ferdinand Helmholtz, later von Helmholtz, was born in Potsdam in 1821, the son of Caroline Penne and high school principal August Ferdinand Julius Helmholtz. He became interested in natural science at a young age, but followed his father’s wishes and studied medicine at the Berlin military academy. He graduated in 1842.