Learning Objectives
- Distinguish between the natural, harmonic, and melodic forms of the minor scale.
Minor Scales VII: Harmonic and Melodic Minor
The Three Forms of the Minor Scale
The minor scale that we have been discussing so far is also known as the natural minor scale. We use the word "natural" to differentiate between this basic form of the minor scale and two common variants that have developed to accommodate the variability of scale degrees 6 and 7 in minor (as described below). These other forms of the minor scale are known as the harmonic minor scale and the melodic minor scale. Listen to the three scales below and see if you can determine by ear how they differ from each other
Natural
| Natural |
Harmonic
| Harmonic |
Melodic
| Melodic |
Now examine the three forms of the minor scale given below (Click "Show Me" to hear them played). Note that they differ by just a few pitches, involving only scale degrees 6 and 7.
The Natural Minor Scale Pattern
| The natural minor scale |
The A harmonic minor scale
The A melodic minor scale
Play these scales on the virtual keyboard below. Notice in particular that:
- The first five pitches are the same in each form of the scale. Only scale degrees 6 and 7 differ.
- The melodic minor scale has two forms: an ascending form and a descending form.
Click this small keyboard icon below.
Keyboard x
Now we will examine harmonic and melodic minor scales in more depth.
The Harmonic Minor Scale
In major scales, there is a half step between scale degrees 7 and 8, with a leading tone resolving strongly upwards to the tonic. Since there is a whole step between scale degrees 7 and 8 in the natural minor scale, the ear is not led up towards the tonic in this way. It is clear that there is a much stronger attraction between scale degrees 7 and 8 when the relationship between them is leading tone to tonic, rather than subtonic to tonic.
The harmonic minor scale restores the attraction between scale degrees 7 and 8 by raising the subtonic a half step, thereby creating a leading tone. The addition of a leading tone to the minor scale creates a stronger sense of a tonal center (since there is a stronger pull towards the tonic). This alteration is extremely common in tonal music. Composers frequently "raise the leading tone" to create harmonies that have a stronger pull towards the tonic.
| Remember |
|
In the example below, an A harmonic minor scale is created by raising scale degree 7 of the A natural minor scale (resulting in a G#). Note that the raised seventh scale degree is always indicated by an accidental in the score. It is not part of the key signature. Minor key signatures are always based on the natural form of the minor scale.
The A harmonic minor scale
Play the A harmonic minor scale on the piano below. Notice that by raising the seventh scale degree, a rather large gap is created between scale degrees 6 and 7 (between F and G#). This interval of one-and-a-half steps is also known as an augmented second. Listen carefully to the distinct sound that it creates in the harmonic minor scale.
The interval of an augmented second is generally considered difficult to read and to sing because it looks like a second on the staff but it really sounds like a minor third (since it contains three half steps). And in melodic lines, the augmented second can sound somewhat strange. These issues are solved by the melodic form of the minor scale.
The Melodic Minor Scale
The melodic minor scale eliminates the awkward augmented second that occurs in the harmonic minor scale by raising both scale degrees 6 and 7 (as illustrated in the example below). This creates a strong upwards pull towards the tonic from scale degree 5, similar to the major scale. In fact, the only difference between the melodic minor scale and the major scale is the lowered scale degree 3 in melodic minor.
| Remember |
|
In the example below, an A melodic minor scale is created by raising scale degrees 6 and 7 of the A natural minor scale (resulting in an F# and a G#). Note that the raised scale degrees are always indicated by accidentals in the score. They are not part of the key signature. Minor key signatures are always based on the natural form of the minor scale.
The A melodic minor scale
The melodic minor scale is the only scale that has a different form when it is ascending and when it is descending (click "Show Me" in the example above to see this illustrated). This is because the strong upwards pull towards the tonic is not needed when moving downwards from the tonic. On the way down, scale degrees 6 and 7 are returned to their natural, non-raised state. Thus, the descending form of the melodic minor scale is exactly the same as the natural minor scale.
The Three Forms of Minor
In practice, composers rarely use any one form of the minor scale exclusively in one composition. Any form of the minor scale can be used as needed within a single piece of music. In fact, you should probably not even think of the natural, harmonic, and melodic minor scales as three distinct scales. You might think instead of a single minor scale in which scale degrees 6 and 7 are variable. Composers can choose to alter these two scale degrees as needed to increase or decrease the strength of motion towards the tonic. This is why lowered scale degree 3 defines the minor mode much more strongly than scale degrees 6 and 7, since these scale degrees are less stable. Again, natural minor is the basic form of minor, and the one on which minor key signatures are based. In natural minor, scale degrees 6 and 7 are in their natural, unaltered positions.