Olson had a continuing interest in music, acoustics, and sound reproduction, and, by 1934, he was placed in charge of acoustical research at RCA. At RCA, Olson worked on a wide range of projects, which included developing microphones for the broadcasting and motion picture industries, improving loudspeakers, and making significant contributions to magnetic tape recording. Like many engineers of the World War II generation, Olson also made significant contributions to military technology as well, particularly to the fields of underwater sound and anti-submarine warfare. After the war Olson, along with Herbert Belar, developed the first modern electronic synthesizer. Equipped with electron tubes, the Mark II Sound Synthesizer was used to compose music, which was recorded and sold to the public.
