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Hexachord ostinato, in cello, which opens Die Jakobsleiter by Arnold Schoenberg, notable for its compositional use of hexachords[1]

In music, a hexachord is a collection of six pitch classes[2] including six-note segments of a scale or tone row. The term was adopted in the Middle Ages and adapted in the twentieth-century in Milton Babbitt's serial theory.


Middle Ages

The medieval hexachordal system (c = middle C)
Note Syllable
ee la
dd la sol
cc sol fa
bb mi
bb fa
aa la mi re
g sol re ut
f fa ut
e la mi
d la sol re
c sol fa ut
b mi
b fa
a la mi re
G sol re ut
F fa ut
E la mi
D sol re
C fa ut
B mi
A re
Γ ut

The hexachord as a mnemonic device was first described by Guido of Arezzo, in his Epistola de ignoto cantu and the treatise titled Micrologus.[3] It was the most basic pedagogical tool for learning new music in the European Middle Ages, and was often referenced in contemporary musical theory.[citation needed] In each hexachord, all adjacent pitches are a whole tone apart, except for the middle two, which are separated by a semitone. These six pitches are named ut, re, mi, fa, sol, and la, with the semitone between mi and fa. These six names are derived from the first syllable of each half-line of the 8th century hymn Ut queant laxis.

Each hexachord could start on G, C or F and the table to the right, reading upwards from the bottom, shows the notes in each hexachord for each of three octaves. Reading from left to right could, within certain limits, permit notes within different octaves to be distinguished from each other. Thus, C (modern c) was "C fa ut" (or "Cefaut"), c (modern c') was "C sol fa ut", and cc (modern c") was "C sol fa". Since the lowest pitch was designated by the Greek letter Γ (gamma, for 'g'), the pitch was known as "Gamma ut" or "Gamut", a term which came to designate the range of notes available, and later, a complete range of anything.[4]

The hexachordal system also distinguished between B (fa in the F hexachord, and known as "B molle" for 'soft B') and B♮ (mi in the G hexachord, and known as "B durum" for 'hard B'). Over time, the soft and hard variants of 'b' were depicted as a rounded '' and a squared-off '' which gradually developed into the modern flat and natural signs.[5]

Since a single hexachord did not cover every possible note in the range of the gamut (only C-A, F-D excluding B natural, or G-E excluding B flat), singers would have to "mutate" between hexachords if the range of a sixth was exceeded or if there was an alternation between B natural and B flat.[5] In this way the "Guidonian" system of multiple hexachords was different from a modern system called solfege, wherein a single set of syllables in one location suffices to name all possible pitches (including, often, chromatic pitches) within a mode.[citation needed]

Because it included B durum, the G hexachord was called hexachordum durum; likewise, the F hexachord was called hexachordum molle. The C hexachord, containing neither B, was called hexachordum naturale.[5]

In the 14th century, this system was expanded to hexachords that would accommodate an increased use of signed accidentals. From this time onward, the use of such notes was called musica ficta.[3]

20th century

Milton Babbitt's serial theory extends the term hexachord to refer to a six-note segment of a twelve-tone row.[citation needed] Allen Forte in his The Structure of Atonal Music redefines the term hexachord to mean what other theorists (notably Howard Hanson in his Harmonic Materials of Modern Music: Resources of the Tempered Scale[6]) mean by the term hexad, a six-note pitch collection which is not necessarily a contiguous segment of a scale or a tone row.[7][not in citation given] Carlton Gamer uses both terms interchangeably.[8]

Sacher hexachord[9]: Eb (Es) A C B (H) E D (Re)

The Sacher hexachord is notable for its use in multiple compositions including Messagesquisse by Pierre Boulez.

See also


  1. ^ Whittall, Arnold. 2008. The Cambridge Introduction to Serialism, p.23. Cambridge Introductions to Music. New York: Cambridge University Press. ISBN 978-0-521-86341-4 (hardback) ISBN 978-0-521-68200-8 (pbk).
  2. ^ Whittall 2008, p.273.
  3. ^ a b Jehoash Hirshberg, "Hexachord", The New Grove Dictionary of Music and Musicians, second edition, edited by Stanley Sadie and John Tyrrell (London: Macmillan Publishers, 2001).
  4. ^ McNaught, W. G. (1893). "The History and Uses of the Sol-fa Syllables". Proceedings of the Musical Association (London: Novello, Ewer and Co.) 19: 35–51. ISSN 0958-8442. Retrieved 2010-02-26. 
  5. ^ a b c Randel, Don Michael, ed (2003). "Hexachord". The Harvard Dictionary of Music (4th ed.). Cambridge, MA: Harvard University Press. pp. 390–391. ISBN 978-0-674-01163-2. Retrieved 2010-02-26. 
  6. ^ Howard Hanson, Harmonic Materials of Modern Music: Resources of the Tempered Scale (New York: Appleton-Century-Crofts, 1960):[page needed].
  8. ^ Carlton Gamer, "Some Combinational Resources of Equal-Tempered Systems", Journal of Music Theory 11, no. 1 (Spring 1967): 32–59. The term "hexad" appears just once, in a table on p. 37; the word "hexachord" also occurs once, on p. 41.
  9. ^ Whittall 2008, p. 206

External links

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Hexachord". Allthough most Wikipedia articles provide accurate information accuracy can not be guaranteed.

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