Template:Short description Template:Infobox musical scale
In jazz, the altered scale, altered dominant scale, or super-Locrian scale (Locrian Template:Music4 scale) is a seven-note scale that is a dominant scale where all non-essential tones have been altered. The triad formed from the root of the altered scale creates a diminished triad, but due to the inclusion of a diminished 11th, the scale comprises the three irreducibly essential tones that define a dominant seventh chord, which are root, major third, and minor seventh and that all other chord tones have been altered. These are:
- the fifth is altered to a Template:Music5
- the ninth is altered to a Template:Music9
- the eleventh is altered to a Template:Music11 (equivalent to a major third)
- the thirteenth is altered to a Template:Music13 (equivalent to a Template:Music5)
- and the minor third can be considered a Template:Music9
The altered forms of some of the non-essential tones coincide (augmented eleventh with diminished fifth and augmented fifth with minor thirteenth) meaning those scale degrees are enharmonically identical and have multiple potential spellings. The natural forms of the non-essential tones are absent in the scale, thus it lacks a major ninth, a perfect eleventh, a perfect fifth, and a major thirteenth.
This is written below in musical notation with the essential chord tones coloured black and the non-essential altered chord tones coloured red.
- <score sound="1"> {
\override Score.TimeSignature #'stencil = ##f \relative c' {
\clef treble \time 7/4 c4^\markup { C altered scale }
\override NoteHead.color = #red des dis
\override NoteHead.color = #black e
\override NoteHead.color = #red ges gis
\override NoteHead.color = #black bes c
}
} </score>
The altered scale is made by the sequence:
- Half, Whole, Half, Whole, Whole, Whole, Whole
The abbreviation "alt" (for "altered") used in chord symbols enhances readability by reducing the number of characters otherwise needed to define the chord and avoids the confusion of multiple equivalent complex names. For example, "C7alt" supplants "C7Template:Music5Template:Music9Template:Music9Template:Music11", "C7−5+5−9+9", "Caug7−9+9+11", etc.
This scale has existed for a long time as the 7th mode of the ascending melodic minor scale.
Enharmonic spellings and alternate namesEdit
The C altered scale is also enharmonically equivalent to the C Locrian mode with F changed to FTemplate:Music. For this reason, the altered scale is sometimes called the Locrian Template:Music 4 scale.Template:Sfn
It is also enharmonically the seventh mode of the ascending melodic minor scale. The altered scale is also known as the Pomeroy scale after Herb Pomeroy,Template:SfnTemplate:Sfn the Ravel scale after Maurice Ravel, and the diminished whole tone scale due to its resemblance to the lower part of the diminished scale and the upper part of the whole tone scale.Template:Sfn
The super-Locrian scale (enharmonically identical to the altered scale) is obtained by flattening the fourth note of the diatonic Locrian mode. For example, flattening the fourth note of the C Locrian scale gives us the C altered scale:
- <score sound="1"> {
\override Score.TimeSignature #'stencil = ##f \relative c' {
\clef treble \time 7/4
c4^\markup { C super-Locrian scale } des es fes ges aes bes c2 }
} </score>
The altered scale can also be achieved by raising the tonic of a major scale by a half step. For instance, raising the tonic of the C major scale by a half step (here spelled as an augmented unison) produces the scale CTemplate:Music-D-E-F-G-A-B-CTemplate:Music:
- <score> {
\override Score.TimeSignature #'stencil = ##f \relative c' {
\clef treble \time 7/4 cis4 d e f g a b cis2 }
}
</score>
The altered scale can also be the major scale with all of the notes except the tonic being flattened. For example, taking the CTemplate:Music major scale and flattening all of the notes except the tonic produces the CTemplate:Music altered scale (see above).
Common usageEdit
Because it contains the essential notes of a dominant seventh chord, it can be used to create melodies over the dominant chord in a jazz context. The added dissonance of the altered notes creates extra tension on the dominant.
See alsoEdit
ReferencesEdit
Template:Reflist Sources
Further readingEdit
- Callender, Clifton. 1998. "Voice-leading parsimony in the music of Alexander Scriabin", Journal of Music Theory 42, no. 2 ("Neo-Riemannian Theory", Autumn): 219–233.
- Tymoczko, Dmitri. 1997. "The Consecutive-Semitone Constraint on Scalar Structure: A Link Between Impressionism and Jazz." Integral 11:135–79.
- Tymoczko, Dmitri. 2004. "Scale Networks in Debussy." Journal of Music Theory 48, no. 2 (Autumn): 215–292.
External linksEdit
- "The Altered Scale for Jazz Guitar", jazzguitar.be