Microtonal music is music that includes intervals outside of those from the customary Western tuning of twelve equal divisions of the octave (12edo). The boundaries of microtonal music are fuzzy for various reasons, namely cultural context and psychoacoustic effects.
Many dictionaries define microtonal music as music that employs intervals smaller than a semitone. However, in contemporary practice, "microtonal music" is any music that isn't 12edo, even if it is in a tuning system that does not use any intervals less than a 12edo semitone step.
Several terms have been proposed with more or less similar definitions. A notable example is "xenharmonic music", coined by Ivor Darreg, which describes music that sounds significantly different from 12edo. There are many gray areas regarding what sort of systems qualify as "xenharmonic" or not, and no rigorous definition seems to be universally acceptable among xenharmonists.
Sometime before 1900, composer Julián Carrillo Trujillo performed experiments on a violin string, using a razor blade to achieve very precise intervals smaller than a semitone, which he called "microtono." Over a decade later, the music theorist Maud MacCarthy Mann began using the term "microtone" to describe Indian sruti intervals that were smaller than a semitone, to differentiate them from quarter tones. In the 1910's and 1920's, there was some discussion as to whether the term was appropriate, or if competing terms, such as "heterotone" or "fraction-tone" etc., would be clearer. By the 1930's, with interest in American Blues music booming, and with people like Ivor Darreg becoming active with new tuning methods, many more terms were proposed, but the terms "microtonal" and "xenharmonic" were most prominent in the English language by the end of the decade.
- What is microtonal music
- Why Microtonality?
- A recovering microtonalist's critical reaction to Why Microtonality
- Microtonalists critical reaction to a recovering microtonalists critical reaction to Why Microtonaltiy?
- Why microtonality
- Whynotnot by Carlos Augusto Scalassara Prando
- Approaches to musical tuning
- What is microtonal music? What is xenharmonic music by Margo Schulter, on UnTwelve's website