The Herbert Belar papers are composed of schematics, notes, and compositions from Belar’s work on acoustical electronics, including a music composing machine, a phonetic typewriter, and the music synthesizer, at RCA Laboratories, from 1943 to 1967. They also include schematics and reports on several projects Belar did for the military during World War II as part of a secret RCA working group called “MAD Lab.” Of special note is a 1955 letter from Robert Moog, then a student at Queens College, requesting information on RCA’s electronic music synthesizer.

Thirty-seven of Belar's lab notebooks (1948-1966) can be found in Record group 26.

Herbert Belar (1901-1997) was an inventor and research scientist in the field of acoustical engineering at the RCA David Sarnoff Research Center in Princeton, New Jersey for thirty-eight years. He developed "hi-fi" recording, the phonetic typewriter, and the electronic music synthesizer. This small collection of Herbert Belar papers reflects the professional daily work of an acoustical engineer from the 1930s through the 1960s. There is significant documentation on the phonetic typewriter, the 200 speech communication system, the music composing machine, and the electronic music synthesizer. Notable inclusions are information related to the development of "hi-fi," film motion pictures sound recording, and phonographic records recording. There is only one file that discusses Belar's work at the MAD Laboratory.