The Altered Scale, Super Locrian, Locrian b4, Diminished Whole Tone | Guitar Lesson with Diagrams, Scale charts, Theory and Licks

The Altered Scale, sometimes referred to as Super Locrian mode, Locrian b4 or Diminished Whole-tone, is the seventh mode of the melodic minor scale.

It is often used over dominant seventh chords, particularly altered dominant chords.

Altered Scale Formula

The formula is 1 (root) - b2 (minor second) - b3 (minor third)  - b4 (diminished fourth) - b5 (diminished fifth) - b6 (minor sixth) and b7 (minor seventh).

In terms of whole and half steps, the scale can be represented as:

Half - Whole - Half - Whole - Whole - Whole - Whole

The Altered Scale is sometimes used to solo over Dominant chords to create tension in jazz lines indeed, it contains one altered fifth (b5), two altered ninth (b9 and #9) and one altered thirteenth (b13).

How To Play The Altered Scale On Guitar?

There are many ways to play the altered scale on a guitar. However, here are some suggested patterns : 

One Octave Shapes

Two Octave Shapes

3 Note Per String Shapes

Remember that you have to learn and transpose them in all twelve keys by moving the tonic to the desired note keeping the same intervals.

Comparison With Dominant Diminished Scale

The altered scale have some common points with the half-whole diminished scale (aka dominant diminished scale).

The formula for the dominant diminished scale is 1 - b9 -#9 - 3 - b5 - 5 - 13 - b7 whereas the altered scale formula is 1- b9 - #9 - 3 - b5 - b13 and b7. 

The half-whole diminished scale is an octatonic scale meaning that it is built of 8 notes. The altered scale contains 7 notes.

Altered Scale Against Dominant Chords

The altered scale is so-called because it contains all four common altered notes generally used to add tension when soloing over a dominant chord.

These four notes altered notes are b9 - #9 - b13 - b5. 

Related Altered Chords 

Altered chords are generally simplified and written "ALT", for example G7b5 or G7b13 can be written G7alt.

There are many possible combinations of altered chords because it's very difficult to play all of those altered notes in a same chord at the same time. So, the choice is yours, you are free to add one or two extensions to your altered chord, which could give several options : 

G7b5, G7b9, G7#9, G7b13, G7b5, G7#5b9, G7b5#9, G7#9b13

and many more...

You need to know that the altered scale sounds good with other altered chords as 7#11 or 7#5, indeed the b5 can be considered as #11 and the b13 as #5.

Here are some guitar neck diagrams of altered chords that fit with the altered scale.

Altered Lick Using a Minor Triad

In this example, we will play a minor triad over G7 to create a strong pull towards CMaj7. Playing a minor triad starting on the b9 of a dominant chord highlight some interesting altered notes as the b9, b13 and #9.

This means that in a II-V-I progression in C major you can play an Ab minor triad over G7alt.

If you have carefully read the previous section of this lesson named "RELATED CHORDS" you will understand that you can play a G7b9 chord, or a G7b13, a G7#9 or even a G7b13#9.

Altered Lick Using The Dominant Pentatonic Scale

The dominant pentatonic scale contains the four notes of a dominant chord namely root (1), major third (3), perfect fifth (5) and minor seventh (b7) with a supplementary note, the second (2) which can be seen as the ninth (9).

The dominant pentatonic scale is commonly used over dominant 7 chords starting on the root, but can be used as a tritone substitution, this is where it gets very interesting.

Indeed, when playing a Mixolydian pentatonic scale starting on the b5 of a dominant chord you highlight three altered notes, the b5 (aka #11), b13 and b9.

The following example takes a 2 - 5 - 1 progression in C major. You can notice the use of the Db7 dominant pentatonic scale over G7. This creates an interesting sound and a bit of tension.