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In music, 72 equal temperament, called twelfth-tone, 72 TET, 72 EDO, or 72 ET, is the tempered scale derived by dividing the octave into twelfth-tones, or in other words 72 equal steps (equal frequency ratios). Play Each step represents a frequency ratio of √2, or ⁠16 + 2 / 3 ⁠ cents, which divides the 100 cent 12 EDO "halftone" into 6 equal parts (100 cents ÷ ⁠16 + 2 / 3 ⁠ = 6 steps, exactly) and is thus a "twelfth-tone" (Play). Since 72 is divisible by 1, 2, 3, 4, 6, 8, 9, 12, 18, 24, 36, and 72, 72 EDO includes all those equal temperaments. Since it contains so many temperaments, 72 EDO contains at the same time tempered semitones, third-tones, quartertones and sixth-tones, which makes it a very versatile temperament.

This division of the octave has attracted much attention from tuning theorists, since on the one hand it subdivides the standard 12 equal temperament and on the other hand it accurately represents overtones up to the twelfth partial tone, and hence can be used for 11 limit music. It was theoreticized in the form of twelfth-tones by Alois Hába and Ivan Wyschnegradsky, who considered it as a good approach to the continuum of sound. 72 EDO is also cited among the divisions of the tone by Julián Carrillo, who preferred the sixteenth-tone (96 EDO) as an approximation to continuous sound in discontinuous scales.

History and use

Byzantine music

The 72 equal temperament is used in Byzantine music theory, dividing the octave into 72 equal moria, which itself derives from interpretations of the theories of Aristoxenos, who used something similar. Although the 72 equal temperament is based on irrational intervals (see above), as is the 12 tone equal temperament (12 EDO) mostly commonly used in Western music (and which is contained as a subset within 72 equal temperament), 72 equal temperament, as a much finer division of the octave, is an excellent tuning for both representing the division of the octave according to the ancient Greek diatonic and the chromatic genera in which intervals are based on ratios between notes, and for representing with great accuracy many rational intervals as well as irrational intervals.

Other history and use

A number of composers have made use of it, and these represent widely different points of view and types of musical practice. These include Alois Hába, Julián Carrillo, Ivan Wyschnegradsky, and Iannis Xenakis.

Many other composers use it freely and intuitively, such as jazz musician Joe Maneri, and classically oriented composers such as Julia Werntz and others associated with the Boston Microtonal Society. Others, such as New York composer Joseph Pehrson are interested in it because it supports the use of miracle temperament, and still others simply because it approximates higher-limit just intonation, such as Ezra Sims and James Tenney. There was also an active Soviet school of 72 EDO composers, with less familiar names: Evgeny Alexandrovich Murzin, Andrei Volkonsky, Nikolai Nikolsky, Eduard Artemiev, Alexander Nemtin, Andrei Eshpai, Gennady Gladkov, Pyotr Meshchianinov, and Stanislav Kreichi.

The ANS synthesizer uses 72 equal temperament.

Notation

The Maneri-Sims notation system designed for 72 EDO uses the accidentals ↓ and ↑ for ⁠1/ 12 ⁠ tone down and up (1 step = ⁠16 + 2 / 3 ⁠ cents), and for ⁠ 1 / 6 ⁠ down and up (2 steps = ⁠33 + 1 / 3 ⁠ cents), and and for septimal ⁠ 1 / 4 ⁠ up and down (3 steps = 50 cents = half a 12 EDO sharp).

They may be combined with the traditional sharp and flat symbols (6 steps = 100 cents) by being placed before them, for example: ♭ or ♭, but without the intervening space. A ⁠ 1 / 3 ⁠ tone may be one of the following ↑, ↓, ♯, or ♭ (4 steps = ⁠66 + 2 / 3 ⁠) while 5 steps may be , ↓♯, or ↑♭ (⁠83 + 1 / 3 ⁠ cents).

Interval size

Below are the sizes of some intervals (common and esoteric) in this tuning. For reference, differences of less than 5 cents are melodically imperceptible to most people, and approaching the limits of feasible tuning accuracy for acoustic instruments. Note that it is not possible for any pitch to be further than ⁠8 + 1 / 3 ⁠ cents from its nearest 72 EDO note, since the step size between them is ⁠16 + 2 / 3 ⁠ cents. Hence for the sake of comparison, pitch errors of about 8 cents are (for this fine a tuning) poorly matched, whereas the practical limit for tuning any acoustical instrument is at best about 2 cents, which would be very good match in the table – this even applies to electronic instruments if they produce notes that show any audible trace of vibrato.

• play diatonic scale in 72 EDO
• contrast with just diatonic scale
• contrast with diatonic scale in 12 EDO

Although 12 EDO can be viewed as a subset of 72 EDO, the closest matches to most commonly used intervals under 72 EDO are distinct from the closest matches under 12 EDO. For example, the major third of 12 EDO, which is sharp, exists as the 24 step interval within 72 EDO, but the 23 step interval is a much closer match to the 5:4 ratio of the just major third.

12 EDO has a very good approximation for the perfect fifth (third harmonic), especially for such a small number of steps per octave, but compared to the equally-tempered versions in 12 EDO, the just major third (fifth harmonic) is off by about a sixth of a step, the seventh harmonic is off by about a third of a step, and the eleventh harmonic is off by about half of a step. This suggests that if each step of 12 EDO were divided in six, the fifth, seventh, and eleventh harmonics would now be well-approximated, while 12 EDO‑s excellent approximation of the third harmonic would be retained. Indeed, all intervals involving harmonics up through the 11th are matched very closely in 72 EDO; no intervals formed as the difference of any two of these intervals are tempered out by this tuning system. Thus, 72 EDO can be seen as offering an almost perfect approximation to 7-, 9-, and 11 limit music. When it comes to the higher harmonics, a number of intervals are still matched quite well, but some are tempered out. For instance, the comma 169:168 is tempered out, but other intervals involving the 13th harmonic are distinguished.

Unlike tunings such as 31 EDO and 41 EDO, 72 EDO contains many intervals which do not closely match any small-number (< 16) harmonics in the harmonic series.

Scale diagram

Because 72 EDO contains 12 EDO, the scale of 12 EDO is in 72 EDO. However, the true scale can be approximated better by other intervals.

See also

• Musical temperament
• Equal temperament

References

1. Hába, A. (1978) . Harmonické základy ctvrttónové soustavy [ German translation Neue Harmonielehre des diatonischen, chromatischen Viertel-, Drittel-, Sechstel- und Zwölftel-tonsystems   English translation Harmonic Fundamentals of the Quarter-Tone System] (in Czech and German). Translated by Kistner, Fr. Leipzig (1927) / Wien, 1978: C.F.W. Siegel (1927) / Universal (1978).{{cite book}}: CS1 maint: location (link)
   

   Revised German edition:

   Hába, A. (2001) . Steinhard, Erich (ed.). Grundfragen der mikrotonalen Musik [Foundations of Microtonal Music] (in German). Vol. 3. Kistner, Fr. (original translation) (rev. ed.). München, DE: Musikedition Nymphenburg Filmkunst-Musikverlag.
2. Wyschnegradsky, I. (1972). "L'ultrachromatisme et les espaces non octaviants". La Revue Musicale (290–291): 71–141.
3. Jedrzejewski, Franck, ed. (1996) . La Loi de la Pansonorité [The Laws of Multitonal Music] (manuscript) (in French). Criton, Pascale (preface). Geneva, CH: Ed. Contrechamps. ISBN 978-2-940068-09-8.
4. Jedrzejewski, Franck, ed. (2005) . Une philosophie dialectique de l'art musical [A Dialectical Philosophy of Musical Art] (manuscript) (in French). Paris, FR: Ed. L'Harmattan. ISBN 978-2-7475-8578-1.
5. Chryssochoidis, G.; Delviniotis, D.; Kouroupetroglou, G. (11–13 July 2007). "A semi-automated tagging methodology for Orthodox ecclesiastic chant acoustic corpora" (PDF). Proceedings SMC'07. 4th Sound and Music Computing Conference. Lefkada, Greece. Archived (PDF) from the original on 15 August 2007. Retrieved 24 April 2008.

External links

• "The Boston Microtonal Society" (official site). Archived from the original on 2011-02-09. Retrieved 2005-12-05 – via bostonmicrotonalsociety.org.
• "Wyschnegradsky notation for twelfth-tone". Archived from the original on 4 April 2023. Retrieved 24 June 2022 – via sagittal.org.
  • "Sagittal" (website main page) – via sagittal.org.
  • "Sagittal notation". The Xenharmonic wiki. Archived from the original on 2022-10-22. Retrieved 2022-06-24 – via en.xen.wiki.
• "Alterations". Ekmelic Music. 27 September 2017. Archived from the original on 4 October 2017. Retrieved 16 October 2017 – via ekmelic-music.org. — symbols for Maneri-Sims notation and others
• Spyrakis, Ioannis. "Η Ελληνική Σελίδα για τη Βυζαντινή Μουσική" [Byzantine music, electroacoustic music, musicology, education] (in Greek and English). Archived from the original on 5 April 2023. Retrieved 19 November 2024 – via g-culture.org.

v t e Microtonal music
Composers	Richard Barrett Béla Bartók Easley Blackwood Jr. Heinz Bohlen Julián Carrillo Franklin Cox Mildred Couper John Eaton Brian Ferneyhough Michael Finnissy Bjørn Fongaard Alois Hába Christiaan Huygens Charles Ives Ben Johnston György Ligeti Stu Mackenzie Claus-Steffen Mahnkopf Joel Mandelbaum Joe Maneri Roger Redgate John Schneider Sevish Ezra Sims Nicola Vicentino Claude Vivier Elaine Walker Ivan Wyschnegradsky La Monte Young
Inventors	Glenn Branca Wendy Carlos Ivor Darreg Adriaan Fokker Lou Harrison Yuri Landman Harry Partch Tui St. George Tucker Nicola Vicentino
Tunings and scales	Non-octave- repeating scales Alpha scale Beta scale Gamma scale Delta scale Lambda scale (Bohlen–Pierce scale) Equal temperament 15 17 19 22 23 24 31 34 41 53 58 72 96 Just intonation Harry Partch's 43-tone scale Double diatonic
Concepts and techniques	Limit Otonality and Utonality Semitone Sonido 13 Xenharmonicity Tonality diamond
Groups and publications	Boston Microtonal Society Genesis of a Music Huygens-Fokker Foundation
Compositions	Beauty in the Beast quarter tone pieces just pieces Mother Sonata for Microtonal Piano Suite for Microtonal Piano Twelve Microtonal Etudes for Electronic Music Media Flying Microtonal Banana K.G. L.W.
Other topics	Enharmonic keyboard Generalized keyboard Modernism (music)

v t e Byzantine music
List of composers
Composers	Romanos the Melodist Andrew of Crete John of Damascus Cosmas of Maiuma Stephen the Sabaite Theodore the Studite Theophanes the Branded Kassia Joseph the Hymnographer Joseph the Confessor Leo VI the Wise Constantine VII Nikephoros Ethikos Gregorios Glykys John Koukouzelis Xenos Korones Joannes Glykys John Kladas John Laskaris Manuel Chrysaphes* Janus Plousiadenos
Theorists	Michael Psellos George Pachymeres Manuel Bryennios
Liturgy	Paschal troparion Octoechos
Forms	Aposticha Canon Cherubikon Byzantine Rite Kathisma Koinonikon Kontakion Akathist Troparion Sticheron
Theory	Petasti 72 equal temperament Byzantine Musical Symbols Echos Octoechos Nenano Neobyzantine Octoechos Hagiopolitan Octoechos Papadic Octoechos Nana (echos) Ison
Instruments	Byzantine lyra Cretan lyra Thaboura Organon
Scholars	Enrica Follieri Solon Hadjisolomos Peter Jeffery Kenneth Levy Oliver Strunk Miloš Velimirović Egon Wellesz
Performers	Greek Byzantine Choir Nikodimos Kabarnos Iakovos Nafpliotis Konstantinos Pringos Thrasyvoulos Stanitsas
Related	Akolouthiai Protopsaltes Cappella Romana Monastery of Stoudios Museum of Ancient Greek, Byzantine and Post-Byzantine Musical Instruments Only-begotten Son School of Ecclesiastic Music
*also music theorist Category

• Equal temperaments
• Byzantine music
• Microtonality