The Natural Minor Scale
The natural minor scale is made up of the root note, major 2nd, minor 3rd, perfect 4th, perfect 5th, minor 6th and minor 7th.
In scale degrees this would be 1 2 b3 4 5 b6 b7
Just as the major scale is used as our palette of notes within a major key, the minor scale is used as our palette of notes in a minor key. The minor scale has a more melancholy sound than the major scale and is usually associated with sad songs.
Minor Key Signatures
In previous lessons, the key signatures were determined by the number of sharps or flats in the key signature. For example, the key of G major has one sharp in the key signature because the G Major scale has one sharp. The key of Eb major has three flats because the Eb Major scale has three flats. Minor key signatures are determined in the same way but it’s important to understand that every minor key shares its key signature with another major key.
We know that C major has no sharps or flats in its scale or key signature – neither does A minor. This makes A minor the relative minor of C major. This also works the other way round – C major is the relative major of A minor.
To work out the relative minor of a major key, you simply count down a minor third from the tonic. To find the relative major, you count up a minor third from the tonic of the minor key.
Harmonic Minor Scale
This scale is the same as the natural minor scale but with a Major 7th instead of a Minor 7th. Here are the scale degrees:
1 2 b3 4 5 b6 7
This scale provides that stereotypical classical sound and the major 7th is used for a stronger pull to the tonic, like in the major scale. This is an important factor in chord progressions as the dominant chord (chord V) in this key is better used as a major chord rather than a minor chord like in the natural minor scale. The harmonic minor is a common scale used in minor keys so it is definitely worth experimenting with.
This scale is quite unusual due to its different ascent and descent. The ascent is the same as the harmonic minor, but with a major 6th instead of a minor 6th.
1 2 b3 4 5 6 7
In its descent, we use the natural minor scale.
1 2 b3 4 5 b6 b7
The notation below shows the scale in both ascending and descending forms:
To understand why we use a different scale in ascent and descent we need to go back to the composers of ‘yesteryear’. The harmonic minor scale has a major 7th, which provides a strong pull back to the tonic. Composers would want to use this pull to provide a stronger sense of resolution. From a chordal perspective, the harmonic minor works well – there’s a nice sense of key and tonal gravity. However, it is slightly problematic from a melodic point of view as the interval between the b6 and 7 is an augmented 2nd, which was seen to be an awkward movement.
By changing the minor 6th to a major 6th, that melodic interval changes to a major 2nd and is much smoother, but we also retain the leading tone resolution to the tonic.
When descending, we use the default natural minor scale with its characteristic minor 7th and minor 6th. The interval between the root note and minor 7th in descent is a major 2nd. A more pleasing interval.
When we write music for the melodic and harmonic minor scales, the key signature remains the same as the natural minor scale. We simply apply accidentals for the raised 6th and 7th degrees as and when we need to. A composition in A minor would use the C Major key signature of no flats or sharps. If we were using the A harmonic minor scale then we would keep the same key signature and simply use accidentals for the G#.
The melodic minor is also used in modern music in both its ascending and descending forms. This scale is often called the jazz minor as used in many jazz improvisations.