octatonic

A scale with 8 tones per octave is called an otatonic scale.

In 12edo, there are 3 possible octatonic scales, both of them composed of interlaced pairs of "diminished-7th" chords. The intervals between degrees in these scales are alternating Large (L) and (s) steps (which in this case are synonymous with tone and semitone, respectively). Integers which designate the degrees of12edo (where C = 0) are given under the letter-names, which in the case of "black-key" notes are arbitrarily chosen.L = 2 degrees, s = 1.

  L  s  L  s  L  s  L  s
C  D  Eb F  F# G# A  B
0  2  3  5  6  8  9  11

C# D# E  F# G  A  Bb C
1  3  4  6  7  9  10 0

D  E  F  G  G# A# B  C#
2  4  5  7  8  10 11 1

These 12edo octatonic scales may also be thought of as being composed of two identical disjunct tetrachords, separated by a "semitone of disjunction".

[from Joe Monzo, JustMusic: A New Harmony]

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updated:

2002.11.4 -- page created

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