Editing Altered scale (section)

{{Short description|Seventh mode of the melodic minor scale}}
{{Infobox musical scale
| name          = Altered scale
| first_pitch   = [[unison|C]]
| second_pitch  = [[minor second|D{{music|b}}]]
| third_pitch   = [[minor third|E{{music|b}}]]
| fourth_pitch  = [[diminished fourth|F{{music|b}}]]
| fifth_pitch   = [[diminished fifth|G{{music|b}}]]
| sixth_pitch   = [[minor sixth|A{{music|b}}]]
| seventh_pitch = [[minor seventh|B{{music|b}}]]
| pitch_classes = 7
| modes         = [[Ascending melodic minor|I]], [[Dorian b2 scale|II]], [[Lydian augmented scale|III]], [[Acoustic scale|IV]], [[Aeolian dominant scale|V]], [[Half diminished scale|VI]], VII
| Forte number  = 7-34
| complement    = 5-34
}}

In [[jazz]], the '''altered scale''', '''altered dominant scale''', or '''super-Locrian scale''' ('''Locrian {{music|flat}}4 scale''') is a [[heptatonic scale|seven-note]] [[musical scale|scale]] that is a [[Mixolydian mode#Modern Mixolydian|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 [[Altered chord#Jazz|chord tones have been altered]]. These are:
* the fifth is altered to a {{music|flat}}5
* the ninth is altered to a {{music|flat}}9
*the eleventh is altered to a {{music|flat}}11 (equivalent to a major third)
*the thirteenth is altered to a {{music|flat}}13 (equivalent to a {{music|sharp}}5)
*and the minor third can be considered a {{music|sharp}}9


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 [[Enharmonic|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, "C<sup>7alt</sup>" supplants "C<sup>7{{music|sharp}}5{{music|flat}}9{{music|sharp}}9{{music|sharp}}11</sup>", "C<sup>7−5+5−9+9</sup>", "Caug<sup>7−9+9+11</sup>", etc.

This scale has existed for a long time as the 7th mode of the [[ascending melodic minor scale]].