Sonido 13
Sonido 13 is a theory of microtonal music created by the Mexican composer Julián Carrillo around 1900 and described by Nicolas Slonimsky as "the field of sounds smaller than the twelve semitones of the tempered scale." Carrillo developed this theory in 1895 while he was experimenting with his violin. Though he became internationally recognized for his system of notation, it was never widely applied. His first composition in demonstration of his theories was Preludio a Colón (1922). The Western musical convention up to this day divides an octave into twelve different pitches that can be arranged or tempered in different intervals. Carrillo termed his new system Sonido 13, which is Spanish for "Thirteenth Sound" or Sound 13, because it enabled musicians to go beyond the twelve notes that comprise an octave in conventional Western music. Julián Carrillo wrote: "The thirteenth sound will be the beginning of the end and the point of departure of a new musical generation which will transform everything." (Wikipedia).
