The Ribbon mic was invented by Harry F Olsen for RCA in the 1930’s, building off of work conducted by Dr Shottky and Gerlach in the 1920’s. The microphone improved immensely on earlier and alternative methods of recording by using a small nickel ribbon as a diaphragm. The only alternative, condenser microphones, relied on carbon granules and capacitive plates to transduce sound into electricity, which introduced quite a lot of noise, while limiting the frequency response significantly (Albert, 1950).
The way Ribbon microphones work is similar to other microphones in that it relies on an electric current. Where it differed was that instead of charging a capacitive plate which would then oscillate carbon granules (as in a telephone or condenser mic), the electric current simply flowed through the Ribbon, which in turn oscillated according to the rarefactions and compressions in the air. This allowed for far wider applications, particularly for music, which tends to span a much broader range of frequencies than that of the human voice which early condenser microphones were designed for (Albert, 1950),(Radio City and Sound Technology).
The dynamic fidelity of the ribbon microphone helped launch music and radio programming from a fledgling industry to a nationwide phenomenon. It had wide arranging civilian and military applications, such as for commercial venues like Radio City Music Hall, and news stations like the BBC, and CBS, as well as a number of military applications i.e. short range radio. (Radio City and Sound Technology).
It also made music recording much easier by greatly simplify the process. Prior to microphones, analog recording methods required complicated systems of pulleys and staging as different instruments were pushed or pulled closer to the ‘cone’ of the phonograph to prevent the louder instruments from dominating the quiet ones. The ribbon mic changed all of this by allowing individual microphones to be placed in front of various instruments to record to the track separately (Sterne, 2003).
Albert, Arthur. "Chapter 5." Electrical Communication. John Wiley and Sons, 1950.
"Connected by Sound." Radio City and Sound Technology. Accessed December 3, 2015. http://www.phy.duke.edu/~dtl/89S/restrict/20thtechnology/20thtechnology.html
Sterne, Jonathan. The Audible Past: Cultural Origins of Sound Reproduction. Durham: Duke University Press, 2003.