microtonesintervals

Microtones are intervals and tunings that lie outside the conventional Western 12-tone equal temperament (12-TET). They include pitches between the standard notes of 12-TET and, more broadly, any division of the octave that yields intervals smaller than a semitone or that uses nonstandard pitch sets.

Approaches to microtonality include dividing the octave into more than 12 equal parts (equal divisions of the octave, or EDOs; for example 24-EDO or 31-EDO) and using tunings based on just intonation with simple whole-number ratios that can create micro-intervals relative to 12-TET. Such systems allow a finer gradation of pitch, enabling intervals not found in standard Western tuning.

Notation and instruments for microtonal music often require new symbols or practices to indicate micro-intervals. Quarter-tone notation uses accidentals to denote pitches between traditional semitones. Performance may rely on keyboard instruments with extra keys, fretless or slide instruments, wind instruments with precise embouchure control, or electronic and computer-based instruments that can produce arbitrary pitches.

Contexts and traditions for microtones appear worldwide. Indian classical music uses shrutis as microtonal steps within raga structures; Middle Eastern and Central Asian traditions employ maqamat and dastgah with pitches between the standard tones; Indonesian gamelan systems also incorporate non-12-tone tunings. In Western art music, composers such as Alois Hába, Julian Carrillo, and Harry Partch developed microtonal scales, instruments, and notations to explore new pitch worlds.

Reception and challenges include greater expressive potential alongside tuning stability, performance practice, and notation complexities, which can pose barriers to widespread adoption.