Altered scale

In music, an altered scale is a scale in which all of the notes of the scale except the tonic have been flattened (lowered in pitch) by an interval of a half step from a major scale. For example, while the C major scale consists of the notes

C D E F G A B C

the C altered scale consists of the notes

C D-flat E-flat E G-flat A-flat B-flat C

Another way to create an altered scale is to sharpen (raise in pitch) the tonic of a major scale by a half step; for example, when we sharpen the tonic of the B major scale, which has the notes

B C-sharp D-sharp E F-sharp G-sharp A-sharp B

we get the C altered scale

C C-sharp D-sharp E F-sharp G-sharp A-sharp C

the notes of which are enharmonic (identical, in the equal temperament system) with the notes of the C altered scale as it was first described on this page.

Another way to look at the altered scale is that it is identical to the seventh musical mode of the ascending melodic minor scale.