Elisha Gray's Music Telegraph

Elisha Gray (August 2, 1835 – January 21, 1901) was an American electrical engineer who co-founded the Western Electric Manufacturing Company. Gray is best known for his development of a telephone prototype in 1876 in Highland Park, Illinois and is considered by some writers to be the true inventor of the variable resistance telephone, despite losing out to Alexander Graham Bell for the telephone patent.

December 29, 1874, Gray gave the first public demonstration of his invention for transmitting musical tones and transmitted “familiar melodies through telegraph wire” according to a newspaper announcement. This was the first electric music synthesizer using self vibrating electromagnetic circuits that were single-note oscillators operated by a two-octave piano keyboard. The “Musical Telegraph” used steel reeds whose oscillations were created by electromagnets and transmitted over a telegraph wire. Gray also built a simple loudspeaker in later models consisting of a vibrating diaphragm in a magnetic field to make the oscillator tones audible and louder at the receiving end.