Julián Carrillo

Julián Carrillo (1875–1965) was a Mexican composer and one of the leading twentieth-century exponents of microtonal music, which he developed under the name Sonido 13 (Sound 13) — music using intervals smaller than the semitone or half step. Born in Ahualulco, San Luis Potosí, of indigenous descent, he studied at the National Conservatory of Mexico and later in Leipzig and Ghent, where he developed the theoretical and practical foundations for his microtonal system.

From the 1920s onward, he conducted intensive investigations into the possibilities of microtonal intervals, working with sixteenth tones, which he considered the smallest interval listeners could readily hear.