Harry Partch (June 24, 1901 – September 3, 1974) was an American composer. He was one of the first twentieth-century composers to work extensively and systematically with microtonal scales, writing much of his music for instruments he built himself, tuned in 11-limit just intonation. Interested in the potential musicality of speech, Partch worked out his first extended scales to notate the inflections of the speaking voice. He built his adapted viola to demonstrate the concept.