Microtonality

Microtonality refers to tuning and composition that uses pitches and scales with intervals smaller than the standard semitone of 12-tone equal temperament. It encompasses quarter tones and a broad family of tunings that divide the octave into more or fewer than twelve equal parts, as well as alternative just or meantone systems that yield nonstandard intervals.

Common approaches include just intonation based on simple frequency ratios, meantone temperament, and various equal tunings such as 24-EDO (quarter tones), 19-EDO, and 31-EDO. Some music uses non-octave scales or multi-octave systems. Notation often relies on special accidentals or dedicated staff to indicate pitches outside standard Western notation.

Historically, interest in microtonality intensified in the 19th and 20th centuries with composers such as Ivan Wyschnegradsky, Alois Hába, Julián Carrillo, and Harry Partch, who built instruments and composed for nonstandard tunings. In Western practice, La Monte Young has pursued long drone pieces based on precise just intervals. Non-Western traditions such as Indian shruti, Arabic maqam, and Persian dastgah also employ microtonal distinctions.

Instruments and technologies for microtonality range from retuned pianos and custom-built instruments to electronic and computer-based systems that allow arbitrary tunings and microtonal keyboards or MIDI mappings. Contemporary composers often devise new instruments or employ synthesizers to realize complex tunings.

Microtonality remains a niche area within music scholarship and composition, but it has influenced contemporary classical, experimental, and electronic music, expanding the range of expressing pitch and harmony and challenging conventional listening expectations.