Microtones

What is microtonal music?

The term microtonal music is a general term for music that makes use of microtones—intervals smaller than a semitone. It refers to music that, in one way or another, deviates from traditional Western pitch relations. It’s a culture-historical notion and represents a striking collection of historic and contemporary musical movements, which have used different ways of ridding themselves from the limitations of twelve tone equal temperament, the tuning which has onesidedly dominated Western music since the eighteenth century. Microtonal music lets the Western composer, musician and listener hear the possibilities and impossibilities of the musical tone-system and changes the outlook on the twelve-tone system.

Microtonal music is a collective name for various kinds of music that use tone systems different from what is customary in Western music. The normal Western scale one can imagine the best using a piano keyboard: from one octave to the other there are twelve keys present, which produce the same amount of tones. The distance from one key/tone to the next is called a semitone; twelve of these semitones make full an octave.
In microtonal tone systems this is different. To go from one particular tone to the next which is one octave higher, more, and often many more steps must be gone through. This means, evidently, that the distance from one tone to the next is smaller than in the usual twelve tone system. Such a smaller distance is called a microtone, or – which would be a slightly better word – a microinterval, as the French and others more aptly call it.
There are numerous methods for building musical tone systems with microtones. More or less familiar systems are the quartertone system (where the octave is divided in 24 quarter tones) and the 31-tone system (where the octave is divided in 31 small steps which are called dieses). But there are also plenty of other systems, for example with 19, 43 and 53 tones per octave. For these said systems applies that they still have a relation in some way with the normal 12-tone system making them sound somewhat familiar. One can also go about in the opposite way by choosing an arbitrary microtonal system, examine its possibilities concerning scales, intervals, chords, etc. and using them in a microtonal composition. 

Why microtonal tone systems?

Why would one choose a (complicated) microtonal tone system, while Western music has flourished for centuries with the relatively simple twelve-tone system? The answer to this question is twofold. In the first place microtonal music creates much more refined nuances with respect to pitch, intervals and chords, and it can be refreshing employing these new sounds and harmonies in musical compositions. In the second place, this aspect hasn’t been mentioned here yet, in some microtonal systems certain traditional intervals can be realised much purer than in the twelve-tone system, which because of its restrictions had to make a compromise with respect to purity. Microtonal systems based on the latter point of departure, are called just intonations. These just intonations are often very complicated systems, which can also lead to the development of new instruments.

Is it out of tune?

What sounds out of tune and what not is merely a matter of habituation. Something sounds out of tune if it’s impure, but what’s pure is a matter of agreement, of a certain norm. It is an agreement of a certain group of people in a certain cultural domain. The longer this norm serves as a value, the more one begins to believe it is the only true norm, like a physical law. For example in the 16th century people were used to meantone tuning, and found equal temperament to sound rather out of tune. Now that we are used to it, we sometimes have to get used to the special character of meantone tuning when we hear it.

Not a new style

Microtonality is not a certain style in music. It concerns only the material with which composers work. But by the use of microtonal tone systems usually music originates that has a wholly new sound, which cannot be brought under the usual denominators of the music of the 20th and early 21st century. Though, even if most microtonal works have been written in this period (in particular after around 1920), a small number is already of much older date, going back to the sixteenth century. In that century it were the theoretically interested composers, who in their attempts to revive the Greek enharmonic tetrachord, wrote the first microtonal music, if we leave the Greeks themselves out of consideration; of their music almost nothing has survived.
On a normal piano it is not possible to realise microtonality (unless the instrument is retuned drastically). On most wind instruments microtonality is applicable with the help of special blowing techniques and fingerings. For the voice, string instruments and the trombone microtones are mainly a matter of practice; these instruments can after all produce any desired pitch. But where microtonal music feels at his best are of course the microtonal musical instruments, instruments with a large number of keys, strings, pipes, frets, et cetera, each tuned to a certain pitch. And obviously in the world of synthesizers and computer music everything is possible for microtones.

Which music is called microtonal music?

Interpretations of what constitutes “microtonal music” can vary. The most literal definition is music with pitch intervals smaller than the Western semitone. These can include, for example, quarter tones, fifth tones, sixth tones, eighth tones, twelfth tones, and sixteenth tones. A broader definition in use today is music with intervals that are not based on the 12-tone equal temperament system. This can include larger intervals than semitones, arising from a tuning system with fewer than 12 tones per octave, or from a mode with fewer than 12 tones, or based on a tuning system with more than 12 tones per octave, or derived from Just Intonation or Renaissance tunings. According to this definition, all such intervals fall under the category of microtonality. Contrary to common belief, a microtone is not the same as a quarter tone. The general term “microtone” is part of microtonality, which is a broader concept that also encompasses the quarter tone.
In classical music microtones occur more often than one would probably think initially. Think for example about vibrato, glissando, small intonation adaptations by string players and microtonal ornamentations by singers. Still this doesn’t make this music microtonal. This is the case if it is based on a microtonal tone system. We therefore call a tone system microtonal if it contains intervals which are smaller than a minor second (semitone), or are not a multiple of it, in other words: “fall between the piano keys”. So the tone system doesn’t necessarily need to have more than 12 tones per octave.
Much non-Western music is microtonal: classical music from India, Turkey, Arabia and Persia, gamelan music from Indonesia, xylophone music from Africa, Byzantyne liturgical music, folk music from Middle- and Eastern Europe, the Caucasus, etc. Western microtonal music, however, is often experimental. 

More about microtonality


An early example of an alternative division of the tone, in other words an early form of microtonality: the division of the whole tone into 5 steps (instead of the usual two), by Fabio Colonna, 1618. Read here also about, among other things, the cembalo cromatica (in Dutch).

Literature

Literature on microtonality and tuning systems in the online archive

Read more about our publications in the online archive.
View the overview of international publications in the Tuning & temperament bibliography.
Read the one-time published journal of the Huygens-Fokker Foundation: Thirty-One. 

Scores

Overview of scores

In the library and archive of the Huygens-Fokker Foundation, in addition to books and documents, there are also many microtonal scores.

  • A list of scores physically available in the library can be found here in the online archive.
  • Click here for an overview in the online archive of microtonal scores published by Diapason Press.
  • A cross-section of compositions in 31-tone tuning can be found here in the online archive.
  • View this document for a complete overview of all compositions for the Fokker organ or works for ensemble with the 31-tone organ (by E. Lievonen).

Microtonalists

Read more about microtonalists

Below is an overview of composers, musicians, and scholars who have been deeply engaged with microtonality:

See here the complete overview of composers, musicians and scholars in the online archive.
Click hier for an overview of organisations for microtonal music in the online archive.
Links to other interesting web pages about microtonality.

 

History

A brief history of modern microtonal music

The modern history of microtonality logically began with the quarter-tone of the 24-tone system, simply by dividing the semitone of the common 12-tone system in two. This development did not arise from idealism aimed at creating a purer tuning, as had been the case centuries earlier, for example with the 31-tone system, but rather from the spirit of late Romanticism to achieve an expansion of artistic and expressive possibilities.
In nineteenth-century Paris, the composer Anton Reicha↗(1770–1836) already speculated about the use of quarter tones in a publication. However, it was only around the beginning of the twentieth century that a few composers actually replaced the twelve equal-tempered tones with the 24 tones of the quarter-tone system. In 1909, the very first composition ever published with quarter tones appeared, namely Zwei Konzertstücke für Violoncello und Klavier from 1906 by the German composer Richard Heinrich Stein↗(1882–1942). In 1912, the Russian composer Arthur Lourié↗(1892–1966) composed his Prélude (Opus 12 No. 2) for quarter-tone piano. From 1916 onwards, the German Jörg Mager↗(1880–1939), a pioneer in early electronic music, began using microtones in his sounds. A year later, the also German composer Willi von Möllendorf↗(1872–1934) started experimenting with his bichromatic harmonium (1917) and composing with quarter tones. Other composers followed relatively quickly, inspired by the prevailing zeitgeist, such as the Czech composer Alois Hába (1893–1973) with his Suite (1918) for piano and his in 1920 published second string quartet, the Mexican composer/violinist Julián Carrillo (1875–1965) and his Preludio a Colón (1922) for ensemble and the microtones of his ‘Sonido 13′ system, which he had been researching since 1895, the American composer Charles Ives↗(1874–1954) with Three Quarter-Tone Pieces for Two Pianos (1923–1924), the Russian-French composer Ivan Wyschnegradsky (1893–1979) with his Deux Chœurs (1926-1927) for mixed choir, four different tuned pianos and percussion, and the American composer Mildred Couper↗(1887–1974) with her quarter-tone ballet music Xanadu (1930).

Europe

In Eastern Europe, it was the Russian composer Leonid (Leonidovich) Sabaneyev↗(1881–1968) who proposed the equal-tempered 53-tone system in Moscow in the 1920s, believing that it approximated just intonation most closely while still allowing modulation to all other keys. Another important figure of that time, alongside Sabaneyev, was Arseny (Mikhailovich) Avraamov↗(1884–1944), who wrote many articles between 1914 and 1916 in Saint Petersburg discussing microtonality as a potential extension of the 12-tone system in the form of ‘ultrachromatic music’, for which he also invented special instruments. In 1923, Georgy Rimsky-Korsakov↗(1901-1965, grandson of the famous Russian composer Nikolai Rimsky-Korsakov) founded the ‘Petrograd Society for Quarter-Tones’. He was known for his unwavering commitment to quarter tones in music, as he made clear in his article ‘The Basis of the Quarter-Tone Musical System’, published in the Russian journal De Musica. In 1927, he organised one of the first public demonstrations and concerts featuring quarter tones in Moscow. Until the early 1930s, he conducted an ensemble for quarter-tone music, which included, among other instruments, the harmonium, and for which he composed microtonal music that, unfortunately, has all been lost. The famous Hungarian composer Béla Bartók↗(1881–1945) also used microtones in his Sonata for Solo Violin (1943). He composed this piece for violinist Yehudi Menuhin, who insisted that all quarter and third tones in the final movement, the presto, be removed. Ultimately, Menuhin studied these microtones, but the published microtone-free version of the piece remains the most well-known.

Towards the middle of the twentieth century, various composers sought other systems than the quarter- and sixth-tone systems and thus came into contact with the fairly pure 31-tone system and the 31-tone organ (Fokker organ) of the Dutch physicist Adriaan Fokker (1887–1972), who composed several short works for it, and who, after the Second World War, managed to initiate a true 31-tone movement in the Netherlands and beyond. The well-known Dutch composer Henk Badings (1907–1987) wrote several works in the 31-tone system, as well as Hans Kox (1930-2019) and many others. Fokker established contact with microtonal pioneers such as Alois Hába and Ivan Wyschnegradsky, but also Julián Carrillo and Edgard Varèse↗(1883–1965), who in his electronic music frequently allowed unconventional pitch intervals to emerge without notating them explicitly as microtones.

Alois Hába (1893–1973) was an influential figure in modern Czech music of the twentieth century and is mainly known for his experimental use of microtones, including quarter-, sixth- and eighth-tone music. His early musical training took place in Moravian folk music, in which he played violin in his father’s group. During his studies at the Prague Conservatory and later in Vienna, Hába was impressed by Schönberg’s athematic style and was influenced by Franz Schreker, who reinforced his radical artistic side. His fascination with microtones arose around 1917 after reading an article on quarter tones, after which he analysed folk songs and developed a systematic approach to microtonal music. He published his first quarter-tone composition, the Second String Quartet, in 1920 and continued experimenting with specially built microtonal instruments, such as a quarter-tone piano and a sixth-tone harmonium. After his successes in Berlin and meeting the composer Ferruccio Busoni↗(1866–1924), who supported his microtonal experiments and had previously philosophised about third tones himself in his Entwurf einer neuen Aesthetik der Tonkunst (1907), Hába returned to Prague, where he received a position at the conservatory despite resistance. His opera Matka (1931), a social-realist work about Moravian peasants, is considered his most important composition and illustrates his socialist beliefs. During the Nazi occupation, his music was banned and his conservatory department closed, but he resumed his work after the war, although after the communist takeover in 1948, he simplified his microtonal style. Hába continued composing into old age and was probably the most prolific microtonal composer of the twentieth century, with works in various genres, including operas, chamber music, and symphonic pieces. His theoretical writings, such as his book Neue Harmonielehre (1927), offered insight into his vision of microtonal harmony but provided little practical compositional guidance. Although his music was technically innovative, the practical feasibility of his microtonal systems proved problematic, and their expressive value was not always convincingly experienced. Despite these criticisms, Hába remains a pioneer in the field of microtonal music and an inspiration for later generations of composers.

The Russian composer and theorist Ivan Wyschnegradsky (1893–1979) is considered one of the foremost pioneers of microtonal music, particularly quarter-tone music. He was born in Saint Petersburg and studied composition at the conservatory, where he was influenced by Alexander Scriabin and his circle. A deep interest in Indian philosophy led him, after a few mystical experiences, to develop his ultrachromatic ideas and later a tempered quarter-tone system, which was more refined than the traditional system but still remained compatible with Western musical practice. After emigrating to France in 1920, Wyschnegradsky had a quarter-tone harmonium built and collaborated with Alois Hába and the firm Grotrian-Steinweg on the development of a quarter-tone piano, which was ultimately realised by August Förster in 1928. Although he possessed such an instrument, he always wrote his quarter-tone piano compositions for two differently tuned pianos, presumably allowing broader performance possibilities. In 1932, he published the influential Manuel d’harmonie à quarts de ton, in which he outlined his harmonic principles. During his lifetime, Wyschnegradsky composed dozens of works in the 1/4- and 1/6-tone systems, for diverse ensembles including orchestra and string quartet. He developed the theoretical concept of ‘pansonority’, in which sound was considered as an unlimited continuum of tones with maximum density, meaning that tones were not tied to a tonal centre but organised according to density and volume. Additionally, he experimented with colour notation, assigning different interval sizes to specific colours, an idea with parallels to the synesthetic approaches of Scriabin. Despite his radical use of microtones, his musical style remained in some sense rooted in Western traditions, ensuring his work was both progressive and recognisable. His influence in microtonal music is lasting, though his specific musical idiom largely remained a sideline in twentieth-century music development.

The Romanian/Israeli composer Mordecai Sandberg↗(1897–1973) advocated that a microtonal music system could form the basis for creating a ‘music of humanity’ that would unite all cultures and transcend local traditions. In 1929, he published an article on his theory of microtonal music, entitled Die Musik der Menschheit: Die Ton-Differenzierung und ihre Bedeutung in Berlin. He devised an advanced system of notation and designed several instruments, among them two harmoniums: one bichromatic model with quarter tones (1926) and another featuring 12th and 16th tones (1929), both constructed by Straube.
Decades after the pioneering work of the German composer Jörg Mager↗(1880–1939), it was the French composer Jean‑Étienne Marie↗(1917–1989) who played a pioneering role in European electro-acoustic and microtonal music. He experimented with a wide range of microtonal scales, including quarter tones, third tones and other divisions, and developed poly-tempered music in which multiple microtonal tuning systems were used simultaneously to create his futuristic sound world.
The new generation of European post-war avant-garde composers also regularly turned to microtonality and alternative tunings in their search for new, unexplored sound material. Karlheinz Stockhausen↗(1928–2007) used microtones in his earliest electronic compositions. In his Studie II of 1954, he developed for the first time a scale without octaves, based on the 25th root of 5, with the ratio 5:1, divided into 25 equal parts. Pierre Boulez↗(1925–2016) integrated quarter tones in his early cantata Le Visage Nuptiel in the (1946–47), but removed them in his second revision of 1989. The French composer Claude Ballif↗(1924–2004) developed his ‘métatonalité’, in which from 1968 onwards, after encountering the music of Wyschnegradsky and Hába, he used microtones as an integral part of his system, which systematically linked tonal and atonal structures. Extensive microtonal applications can be found in the work of Iannis Xenakis↗(1922–2001), mainly in his chamber music composition Anaktoria. Quarter tones were occasionally used as colour effects, for example in Ramifications by György Ligeti↗(1923–2006), in which it functions as mistuned music.
In 1970, the composers Franz Richter Herf↗(1920–1989) and Rolf Maedel↗(1917–2000) began systematic research into microtones at the Mozarteum in Salzburg (Austria), leading to the founding of the Institute for Fundamental Musical Studies in 1972, where their focus lay primarily on the 72-tone system. In 1974, they designed the ‘Feinstufenorgel’, an electronic organ with 72 notes to the octave. From that point onwards, they composed exclusively within this system, constructing melodies, harmonies, and chords from small micro-intervals. In 1981, the International Society for Ekmelic Music was founded to organise concerts, publications, and symposia.

Representatives of the spectral music movement in France had groups of instruments often play microtones, such as quarter tones and even sixth and eighth tones, in an attempt to reconstruct the overtones. Spectralism emerged in the mid-1970s and is closely associated with the French composers Gérard Grisey↗(1946–1998) and Tristan Murail↗(1947–), who together with Hugues Dufourt↗(1943–) are considered the founders of this movement. Spectralists base their compositions on the natural resonances and overtone spectra of sounds, leading to an approach where the boundary between timbre and harmony is blurred. Microtones play regularly a role in this, but not as an end in themselves: they are a natural consequence of striving for an accurate approximation of overtones and are mainly applied vertically, making them less often a melodic element. Gérard Grisey, one of the movement’s key exponents, emphasised that he did not consider microtones as an extension of the twelve-tone system to a microtonal system, but as a necessary consequence of working with the spectral structure of sounds. His influential cycle Les Espaces Acoustiques (1973–1985) demonstrates clearly that microtones do not stand alone but serve to create harmonic layering and refinement of timbre. Although spectralism has never been a strictly defined method and Grisey himself regarded the term as a ‘sticker’, this approach has had a lasting impact on contemporary music.
Beyond France, spectralism resonated in other countries, such as with the Finnish composer Kaija Saariaho↗(1952–2023), who used microtones not only for timbre but also for structural development in her music, and the Belgian Luc Brewaeys↗(1959–2015), who combined spectral techniques with theatrical elements. In Great Britain, Jonathan Harvey↗(1939–2012) was inspired by spectralism and integrated microtones intuitively in his music, sometimes without systematic approach, purely as an effect. The Hungarian-French composer Horațiu Rădulescu↗(1942–2008) also developed a spectral style from the 1970s onwards, but from a completely different perspective than Grisey and Murail. The spectral approach was further developed at IRCAM in Paris, where composers used computers to refine spectral analyses and sound models, resulting in the distinct sound world characteristic of this music. Younger composers such as Philippe Hurel↗(1955–) and Marc-André Dalbavie↗(1961–) combine spectralism with other approaches, while an even younger generation explicitly distances themselves from it, though they remain influenced. In the composition in vain by the Austrian Georg Friedrich Haas↗(1953–), many spectral sounds are also audible, as well as in many of his other compositions. Another microtonalist who bases his music on the overtones but thinks more from the perspective of just intonation is the French composer Jacques Dudon↗(1951–), who builds experimental musical instruments himself. Also the Canadian composer Marc Sabat↗(1965–), residing in Berlin since 1999, uses overtones and microtones in his ongoing quest for just intonation and to specifically construct the harmonic relationships of overtones and resonances.

A less well-known but very active post-war microtonal composer in Europe was the Norwegian composer Bjørn Fongaard↗(1919–1980). Fongaard was for a time better known as a guitarist than as a composer. He developed a guitar in which the octave could be divided into 12, 24, or even more tones per octave, as part of his new ‘universal’ principle of tonality. This instrument is prescribed in many of his works. Selected compositions from Fongaard’s extensive oeuvre include Microtonal Structures for Chamber Orchestra, Op. 135 (1970) and Mora Parva Infinitatis, Op. 93 (1974) for string quartet, soprano, and micro-interval guitar. His work is rarely performed due to his unusual and complex music notation system. Another post-war representative of microtonal music in Europe is the Frenchman Alain Bancquart↗(1934–2022), who frequently used microtones in his music, such as in his composition Labyrinthe du Minotaur (2000) for ensemble and tape, in which, in addition to quarter tones, even sixteenth tones occur. Sixteenth tones are also used by the French composer Pascale Criton (1954–), a student of the quarter-tone pioneer Ivan Wyschnegradsky. Criton specialises in works for the 96-tone piano, often using two differently tuned synthesizers.

Many contemporary composers have occasionally experimented with microtones. Examples of compositions by European composers who sporadically used microtones include Sonate für Viertelton-Klarinette und Viertelton-Klavier by Viktor Ullmann↗(1898–1944), Lukaspassion (1963–65) by Krzysztof Penderecki↗(1933–2020), Stringquartett II (1964) by Ton de Leeuw (1926–1996), Életút by György Kurtág↗(1926–), Musik für Flöte, Streicher und Schlagzeug (1994) by Sofia Gubaidulina↗(1931–), Studie VI (1969) for tape with quarter tones by Lucien Goethals↗(1931–2006) and ballet music L’Envol d’Icare (1932) by Igor Markevitch↗(1912–1983).

Other composers used microtones more regularly, such as the Italian Giacinto Scelsi (1915–1982) in for example In Xnoybis (1964) for flute and clarinet. After 1956, Scelsi developed a style in which he used quarter tones in an almost systematic way through subtle pitch fluctuations, often integrated into timbre rather than employed as purely melodic material. The British composer Clarence Barlow↗(1945–2023) also makes frequent use of microtones within his mathematically generated pitch sequences, as in, among other works, his Çogluotobüsísletmesi (1982) for four pianos with detuned strings. Another example is the British composer, percussionist and conductor James Wood (1953) who, as a convinced microtonalist, not only composes microtonal music, but also designs and builds microtonal instruments such as a quarter-tone marimba and glockenspiel. As a former pupil of Xenakis, the music of the French composer Pascal Dusapin↗(1955–) is likewise characterised by microtonality, in which he integrates microtones and micro-glissandi into his melodic progressions.
An important discovery within microtonality from the 1970s and 1980s that must certainly be mentioned, and which took place in both Europe and America, is the Bohlen–Pierce scale. This scale, named after Heinz Bohlen (1935–2016) and John Pierce (1910–2002), is a microtonal tuning system in which the interval 3:1 (“tritave” instead of the usual 2:1 octave) is divided into 13 equal steps. As a result, unusual micro-intervals arise that differ from the traditional even and uneven ratios of classical scales. Bohlen and Pierce, who coincidentally were both engineers in microwave electronics and communications, each discovered this scale independently with an interval of roughly ten years between them. Several composers have since written works for this remarkable system, among them the German composer and musicologist Manfred Stahnke↗(1951), who, as a microtonalist and former pupil of György Ligeti and Ben Johnston, is interested in just and alternative tunings.

America

In the United States, microtonality also flourished greatly in the 20th century. After the occasional excursions into quarter tones by Charles Ives↗(1874–1954), it was Harry Partch↗(1901–1974) who emerged as a key figure in the field of microtonality; a visionary and individualistic composer, theorist, and musical instrument inventor, who challenged the dominance of equal‑tempered 12‑tone tuning in Western music. He was an influential figure in the development of experimental American contemporary music, pioneering the discovery of new instruments and tunings. Partch created multimedia theatre in which sight and sound were integrated, based both on Greek mythology and on his own experiences as a wanderer during the Great Depression. In 1930, Partch broke with the Western European tradition and forged a new kind of music based on a more primal and organic integration of speech elements with music, using natural acoustic resonance and extended melodic and harmonic possibilities. Partch advocated, among other things, a system with 43 unevenly divided tones in the octave, based on just intonation. His book Genesis of a Music (The University of Wisconsin Press, Madison, 1949), first published in 1949, is now considered a classic; it addresses his theories, instruments, compositions, and ideas about music, and also contains autobiographical elements. Largely ignored by standard music institutions during his life, he criticised the conventional concert practices, the roles of the performer and the composer, the role of music in society, equal‑tempered 12‑tone tuning, and the concept of abstract music. Harry Partch composed slightly fewer than 30 works in his lifetime, including several operas such as Oedipus (1952), Plectra and Percussion Dances (1952), Revelation in the Courthouse Park (1961), and Water Water! (1962). Partch is recognised as an important inspiration for post-war experimental composers such as György Ligeti and Lou Harrison.

Lou Harrison↗(1917–2003), an outspoken microtonal composer, music theorist, and builder of unique musical instruments, was particularly known for his use of non-Western instruments such as the gamelan, but also his own instruments, made for example from tin cans. He initially composed in an ultra-modernist style but later incorporated elements from non-Western cultures into his work. Harrison created his own musical ensembles and wrote most of his works for specially adapted instruments in just intonation, making him one of the most prominent American composers experimenting with microtones.
In the mid-20th century, other microtonal thinkers also emerged in the United States, such as Ivor Darreg (1917–1994), who coined the alternative term “xenharmonic music” for microtonal music, meaning “strange music”, derived from the Greek word xenos (strange, foreign) and harmonikos. Darreg used this term to refer to all music not based on the 12-tone equal temperament, effectively encompassing all definitions of microtonality. The noun form is xenharmonics.
Another important figure was Erv Wilson↗(1928–2016), who in Japan by chance encountered natural overtones. Influenced by the work of the Mexican Augusto Novaro↗(1891-1960) and the Russian American Joseph Yasser↗(1893-1981), who both explored several tuning systems as alternatives to the standard twelve-tone system, Wilson began to view the scale as a living process, like a plant. Wilson became an inspiration for those interested in microtonal music, just intonation, and keyboard and notation design. He built instruments and explored sources for 31- and 41-equal divisions of the octave, supporting the work of Harry Partch.
American composer Ben Johnston↗(1926–2019) became known primarily for his works in just intonation, based on pure, rational intervals. After meeting Harry Partch and studying with John Cage, among others, he developed microtonal notation from 1960 onward, using hundreds of notes per octave and constructing complex harmonies that are based on the overtone series. In his later works, such as string quartets, he used intervals up to the 31st overtone, employing microtones to rediscover a musical beauty he felt was lacking in the conventional equal temperament system.

Ezra Sims↗(1928–2015) was also a pioneer in microtonal music. He invented a notation system adopted by several microtonal composers. His first microtonal composition was written in 1960. His last composition in quarter tones (his sixth microtonal work) was his Third Quartet (1962), after which he also began using sixth tones. From 1971 onwards, he composed music using the equal-tempered 72-tone system.
Another prominent microtonalist is the pianist, composer, and music theorist Easley Blackwood↗(1933–2023), who studied with Olivier Messiaen, Paul Hindemith, and Nadia Boulanger. Blackwood wrote many études experimenting with 13 to 24 tones per octave. In these compositions, he regularly attempted to combine conventional music with microtones. He began this tonal style in the early 1980s after initially composing in a more modernist style, and this stylistic shift brought him both praise and criticism.
The American minimal music pioneer Terry Riley↗(1935–) employed microtones and just intonation tunings in several compositions. An important example is Shri Camel (1980), in which he uses a specially tuned electric organ in just intonation, producing microtonal sounds. Influenced in part by his study of ragas in Indian classical music, with subtle microtonal nuances and gliding pitches, Riley incorporated such techniques into his compositions.
In a completely different way, the Canadian composer Claude Vivier↗(1948–1983) used, in various compositions, his technique of ‘les couleurs’, in which combination tones or overtones emerge from harmonies, thus creating sound fields that are not based on explicitly notated microtones, but on constantly shifting, naturally generated microtonal intervals. A less known Canadian composer is Bruce Mather↗(1939), who from the 1970s onwards was strongly influenced by Ivan Wyschnegradsky and has since frequently used microtonal scales. In addition, he composed specifically for the 96-tone piano. 

Much of the work of the Canadian-American composer and pianist James Tenney↗(1934–2006) was composed with alternative microtonal tunings, such as the 24-tone and 72-tone systems or based on just intonation, and he experimented with precise acoustic and mathematical principles in both acoustic and electronic music. As a pianist, he performed in ensembles of John Cage, Philip Glass, Harry Partch, and Steve Reich. He was also a scholar of the music of Conlon Nancarrow and author of A History of ‘Consonance’ and ‘Dissonance’ (Excelsior, 1988). An example of an important work is Spectrum (1961) for tape in just intonation. A relatively recent work by Tenney using quarter-tones is Flocking (1993), for two quarter-tone pianos. Tenney also influenced Alvin Lucier↗(1931–2021), who played a modest role in American microtonal music, often with an experimental approach based on physics rather than conventional microtonal tuning systems.
The New York composer and bassoonist Johnny Reinhard (1956–) has also been very active in the United States over the past decades with just intonation in the microtonal world and has emerged as one of the most important advocates of microtonal music in the USA and beyond. Among contemporary American composers of microtonal music are also Joel Mandelbaum (1932–), John Eaton↗(1935–2015), Kraig Grady↗(1952–), Kyle Gann↗(1955–), Elaine Walker↗(1969–), and many others. In the late twentieth century, microtonal composers in the United States were somewhat divided into two camps. In the eastern part of the country, composers often worked with alternative octave divisions, such as the 19-tone, 22-tone, or 72-tone systems. On the west coast, composers were more interested in pure tunings, such as just intonation. It was there in Los Angeles that the festival MicroFest, organised since 1997 by the microtonal guitarist John Schneider↗(1950–), contributed to the popularity of microtonal music.

Finally, attention must be paid to an early microtonalist from Central America. The Mexican composer Julián Carrillo (1875–1965) dedicated his entire life to experimenting with microtones, although his music is clearly thematic and classically structured, with long-spun sequences. Around 1924, he largely relinquished his official positions to devote himself entirely to composing and developing his octave division in up to 96 tiny steps, the Sonido Trece system (the thirteenth tone). This tuning system also incorporates the quarter-tone system and the eighth-tone system. In many compositions, Carrillo uses these various systems interchangeably, with the choice of system depending on the possibilities of the instrument in question. He had a special series of pianos built for his microtonal system, whose keyboards looked normal but whose sound was highly unusual. The complete keyboard of the 96-tone piano, with 97 keys, spans only a single octave. To notate his music, Carrillo used, in addition to a system of small lines placed before the notes, sometimes a numerical notation, assigning each pitch in the octave a number from 1 to 96. An example of such a composition is Sonata si fantasia (1926), a 1/16-tone work. His ensemble piece Preludio a Colón (1922) is the best-known work of his oeuvre. In Mexico, Carrillo and his students established an orchestra capable of performing 1/4-, 1/8-, and 1/16-tone music. He also founded a choir for microtonal music. In 1927, he designed a plan for fifteen different pianos for 1/3, 1/4, and so on up to 1/16-tone systems. It was not until 1949 that the first 1/3-tone piano was built by Buschmann in Mexico and played by Carrillo’s daughter Dolores. In 1957, 14 more microtonal pianos were built by Sauter in Germany and exhibited at the World Expo in Brussels in 1958. Carrillo is regarded as one of the greatest pioneers of early microtonal music.

World

Throughout the twentieth century, composers around the world regularly used microtones in their music. The Iraqi avant-garde composer Farid Al‑Awerdi↗(1923–2007) is one of many composers from the non-Western world who drew upon microtonal intervals from the traditional music of their region. In some of his work, he made explicit use of quarter tones and microtonal tunings, inspired by the Arabic maqam systems. At the other side of the world, in Australia, the composer Bill Coates↗(1917–1997) became interested in microtonal music from the 1950s onwards and composed, among other works, simple but effective 31‑tone music for his archiphone, often in combination with other instruments.

Microtones are increasingly used in jazz and popular music, especially in alternative music scenes. In jazz, microtones often arise through playing techniques such as ‘bending’ and blue notes, where pitches are subtly raised or lowered without a fixed system. The ‘blue third’, a note between the minor and major third, also called the neutral third, is a common example. In the USA, jazz trumpeter Don Ellis↗(1934–1978), who was playing on a quarter-tone trumpet, and jazz saxophonist, clarinetist and pianist Joe Maneri↗(1927–2009), who explored the 72-tone system, were pioneers in microtonal jazz. Maneri did not use microtones as an effect but as fully fledged melodic and harmonic material within his system of 72 tones per octave. Although he had been active as a performer and teacher since the 1960s, his microtonal work only began to receive wider recognition from the 1980s onwards, especially thanks to his ECM recordings in the 1990s, including the influential Three Men Walking (1996). In 1988 he founded the Boston Microtonal Society and was deeply involved in both academic and microtonal circles. With ensembles such as the Joe Maneri Quartet and through his collaborations with his son Mat Maneri, he became a leading figure in avant-garde jazz and microtonal improvisation.
Microtones also appear in pop music, such as in City Lights by Lou Reed↗(1942–2013), in which off-pitches produce an expressive effect. Despite these experiments, microtonal music remains a niche within the world of popular music.

Since the beginning of the 21st century, a significant group of composers and musicians has been experimenting with all possible octave divisions and composing music accordingly. These compositions are, due to the lack of microtonal instruments, largely performed using computer sound cards or synthesizers, but in fortunate cases also by acoustic instruments and music ensembles. Many composers of non-microtonal music also occasionally venture outside the conventional 12-tone system for colouristic effects. The advent of advanced music software with microtonal playback capabilities in the 21st century has made it easier than ever to explore the use of microtones, resulting in a worldwide ‘eruption’ of creative activity in microtonality. (Sander Germanus, 2005 – sources via the Huygens-Fokker Foundation – last update 2025)