Altered Scale

Altered Scale

The altered scale is called altered because it contains all the possible alterations to a dominant 7th chord. 

It is also known as the 7th mode of melodic minor. Like lydian dominant, this scale is so common in jazz that it must be given its due. 

Because the scale has four altered notes, the scale cannot be properly spelled. There is always going to be a note duplicated and one omitted. But here they are:

1   b2   b3   3   b5   b6   b7

In the key if C:

C   Db   Eb   E   Gb   Ab   Bb

The reason this scale is used so much is because the scale contains the tri-tone structure between the 3 and the b7 which is the core of the dominant sound, but also contains all of the common alterations applied in jazz to the dominant chord. 

Therefore, this is the scale of choice if you come across a dominant chord with b9, #9, b5, or #5 alterations.

With that being said, this scale is very dissonant. Its use mirrors its parent chords use, which is to create maximum tension around the dominant tri-tone structure, in order to have a more exaggerated resolution of that tension with the arrival of the next chord.

It is also important to note that even though it is not listed in the scale degrees, the 5th is commonly played with the altered scale.  This is because the 5th is part of a dominant chord, as well as being great for melodies.

Below are the five patterns of the altered scale along with some progressions for you to improvise over. You know what to do.

Jam Tracks:

1.  B altered - Ima7 - V7ALT

2.  A altered - Ima7 - V7ALT

3.  Db altered - Ima7 - V7 ALT