03: The Octatonic Scale

Each of the commonly used major and minor scales and their modal relatives is comprised of seven notes. An octatonic scale has, as its name suggests, eight notes. There are many possible eight note scales ( I read somewhere that there are 42) but there is one in particular that is most commonly used and in fact is often referred to as “the” octatonic scale.

Messiaen refers to it as the ’second mode of limited transposition’.

It is also known in jazz and guitar circles as the ‘diminished scale’.

This particular scale is comprised of alternating tones and semitones and has two modes:
Mode 1: TSTSTSTS
Mode 2:   STSTSTST
For example:
Mode 1: C Db Eb E F# G A Bb
Mode 2:    Db Eb E F# G A Bb C

It is only possible to have three transpositions of this scale (mode 1 starting on, say, C, Db or D) before ending back on the same notes you started with. Starting on Eb will give you exactly the same set of notes as starting on C (or F# or A), hence Messiaen’s name for it.

The scale can be seen to be constructed of two interlocking diminished-seventh chords (C, Eb, Gb, A and C#, E, G, Bb), hence its jazz description.

Rimsky-Korsakov claimed to be the first to use the scale although there are instances to be found in earlier music, even back in 7th century Persia. Nuages from Nocturnes by Debussy is largely built on the octatonic scale.

Rimsky-Korsakov’s pupil, Stravinsky incorporated the scale in a number of works, including The Rite of Spring and the Symphony of Psalms.

Scriabin,

Bartok (octatonic until the singing starts),

Messiaen and Takemitsu, explored it in combination with other modes. John Adams has used it melodically while harmonising it freely, (The Wound-dresser, El Dorado, Violin Concerto Mvt 1).

Red by King Crimson’s Robert Fripp: