The papers of Adolph R. Morgan include evidence of his work with underwater communications, microphones, and noise cancellation of underwater sounds.

One of Morgan's lab notebooks (1954-1960) can be found in Record group 26.

The Audio series contains images related to non-broadcast sound equipment. The series is organized into eleven subseries: Commercial sound equipment, Equipment, Intercom, Loud speakers, Manufacturing sets & records, Meters, Microphones, Phonographs & transcriptions, Record changers, Sound trucks, and Speakers. The series materials date from 1930 to 1977. The Meters subseries are primarily images of audio meters like decibel and acoustic gauges measurements, but it’s possible other types of meters are in this subseries related to broadcasting. Additionally meters appear in other series such as the Radio/TV broadcasting series.

The Harry F. Olson papers include schematics and drawings, a body of articles and patents, and correspondence from Olson’s work in acoustics at various RCA research divisions.

Photographs include, predominantly black and white with a few color, images of loudspeakers, microphones, and the magnetic video tape recording system.

Sound tape reels contain over 40 recordings of 'word lists' presumably used by Olson in his work with the phonetic typewriter.

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.

Harry O. Sooy (1875-1927) worked at Berliner Gramophone Company and Victor Talking Machine Company and was involved in the development of American sound recording. His papers contain a diary photocopy that is either a typed original or transcript of a diary that Sooy kept from the time of his employment with Eldridge R. Johnson (1867-1945) from 1898 to the end of 1925. Also included are four miscellaneous items: formula for grading and grinding precious stones, regulations governing the Victor Cooperative Beneficial Association, Red Cross benefit concert, and United War Work Campaign concert.