Escala del momento

As we have seen in the first part of this chapter, we shall call scale of the moment that modal scale or scale relative to the chord on which it is sounding, taking into account the arpeggio notes and the superstructure deriving from it.

We shall thus define the modal or the relative scale corresponding individually to each chord in a progression, beyond the fact that the chords and their corresponding scales be diatonic to a common scale or not.

Scale of the moment

When we face a non-diatonic chord, the simplest way to determine the corresponding scale for building a melody or a solo is to apply the concept of scale of the moment following the steps:

1.- Determine the key of the chord progression (harmonic analysis).

2.- Write the scale of that key beginning from the tonic of the chord in question (modal scale).

3.- Substitute in the resulting scale for the non-diatonic degrees of that chord.

Let us look at an example:

Scale of the moment 06

We shall look for the corresponding scale for A7, which is the non-diatonic chord:

1.- The key is C major.

2.- Build the scale of C major starting from A (Aeolian mode).

3.- Replace the note C of the scale by C#, which is the non-diatonic note of A7 (the 3 of the chord).

Scale-of-the-moment-03

With this method, the resulting scales will have the same name of the most similar modal scale in reference to its structure and the tonal function of the chord, plus an indication of altered tensions further appearing.

In the same example, A7 will be a secondary dominant (V7/II) and, as a dominant chord, the corresponding scale will be the Mixolydian.

As may be seen, in the momentary scale, b13 (F) appears instead of 13 (F#), as in the Mixolydian scale. Therefore we call this scale Mixolydian b13, as simple as that.

Scale-of-the-moment-02

If we pay attention to the 7 notes of the resulting scale, we shall notice that these notes coincide with those of the melodic minor scale of D minor, but starting from the V degree (A).

This is what we have seen before with the relative scale of the V degree of the melodic minor.

Scale-of-the-moment-01

Therefore, we shall say about this example that the Mixolydian scale b13 in the scale-chord relationship will correspond to the V7/II, and is relative to the melodic minor scale from the V degree.

Using the same criterion, we shall analyze all altered Mixolydian scales in the next section.

This post is part of my book