Telharmonium

Tel′har‐mo″ni‐um (?), n. [Gr. τη̑λε far + harmolium.] An instrument for producing music (Tel‐har″mo‐ny), at a distant point or points by means of alternating currents of electricity controlled by an operator who plays on a keyboard. The music is produced by a receiving instrument similar or analogous to the telephone, but not held to the ear. The pitch corresponds with frequency of alternation of current.