7. MINOR SCALES
If, in any Major scale, we change the tonic but keep all its notes, what we obtain is a new Mode. For example, if in the C Major scale, we choose the note E as the tonic, the resulting scale is: E, F, G, A, B, C, D, E. This is not a Major scale, since it does not keep to the interval succession W W H W W W H, but it is a mode associated to the C Major scale. Therefore, there are 7 possible modes for any Major scale, one for each note in the scale that is considered the tonic. In fact, the name “Major” is, precisely, the name given to the mode with the interval succession W W H W W W H.
Western music has evolved with time to the so called Major-minor System, which means that, from the 7 possible modes, only two of them remained: the Major and the minor modes. The minor mode is that obtained by considering the VI degree in the Major scale as the tonic. So, from the C Major scale, the so called “A natural minor scale” is obtained:
A natural minor scale, along with its degrees
These two scales, C Major and A natural minor, are said to be relative to one another. In the same way, from the B Major scale, the G natural minor scale is obtained. And, from the A Major scale, the F natural minor scale is obtained.
In general, we can define a natural minor scale as a set of 7 notes characterized by the following interval succession: W H W W H W W. Logically, a Major scale and its relative minor have the same key signature. In Chapter 13, the special characteristics of these two modes will be studied, as well as the reason why they prevail over the rest of the modes.
Nevertheless, the natural minor scale has an inconvenience: the distance between its VII and VIII degrees is one whole step, while in a Major scale this distance is one half step. So, it turns out that, when playing the natural minor scale and passing from the VII to the VIII degree, it does not produce the sensation of having reached the end of the scale. In Music, it is said that the VII degree of the natural minor scale does not have the Leading tone character and so it is called Subtonic instead. In order to avoid this inconvenience, it is common to raise one half step the VII degree of this scale by means of an accidental, which results in the harmonic minor scale.
A harmonic minor scale, along with its degrees
However, in the so built harmonic minor scale, an A 2nd interval appears between its VI and VII degrees, that is, 1.5 W, which has a strange and unnatural effect, for it is a too big interval for being between two consecutive degrees. So, sometimes the VI degree is also raised one half step by means of another accidental, thus solving this problem. This results in the melodic minor scale, where the interval between two consecutive degrees is always one whole or one half step.
A melodic minor scale, along with its degrees
Finally, since the Leading tone character associated to the VII degree is only needed in the ascending scale, but not in the descending, it is also common to use the melodic minor when ascending the scale and the natural minor when descending the scale. This combination is occasionally known as the classical melodic minor scale, although sometimes it is called, simply, the “melodic minor scale”, what can lead to confusion. In this context, it will be assumed that the “melodic minor scale” is the one having the VI and VII degrees raised one half step, both ascending and descending.
By means of a similar procedure to that seen for the Major scales, the Harmonic Wheel also allows us to obtain the notes of any minor scale, being it natural, harmonic or melodic. Moreover, if we pay attention to the red notation, we will see that each key signature is next to two “notes”, one of them followed by the letter “m” for minor (actually, what the red notation represents are chords, as will be seen in Level 2). These two notes are, precisely, the tonics of the Major and its relative minor scales having this key signature (all of which will be explained in detail in Chapter 12).
As examples of this, Fig. 8 shows the following cases: For 2, the tonics of the B Major and G minor scales; for 2, those of the D Major and B minor; for 3, those of the A Major and F minor; and, for no accidentals, those of the C Major and A minor scales. This information must be sufficient to play all the Major and minor scales, with all the minor scale variants (natural, harmonic, melodic and classical melodic), by mentally obtaining the notes.
Figure 8. Tonics of the Major and their relative minor scales, along with their corresponding key signatures.