The Minor Mode
A mode is a scale with characteristic qualities. There are two principal modes in Western classical and popular music: major and minor.
Words such as dark or melancholic are often used to describe music in the minor mode, though minor mode music can also be upbeat, even exhilarating!
The Minor Scales
While keyboard players typically practice several different minor scales, they can all be understood as originating from one theoretical “source scale”:
The consistent difference between the major and minor modes is the third degree of the scale. The three minor scales shown below all contain the lowered third of the source minor scale, while the sixth and seventh degrees may be lowered (altered from the major scale) or natural (same as the major scale).
The Natural Minor Scale
The natural minor scale contains the lowered third, lowered sixth and lowered seventh degrees of the source minor scale. It is identical to the Aeolian mode. The C natural minor scale is:
The natural minor scale uses the same notes as its relative major scale (see Parallel and Relative below).
The natural minor scale is rarely used in music composition, but is useful for understanding key signatures and music theory.
The Melodic Minor Scale
The melodic minor scale differs in its ascending and descending forms. The ascending form uses a lowered third, natural sixth and natural seventh:
The natural sixth and seventh have a stronger and more satisfying tendency to lead up to the tonic in ascending melodies.
The descending form uses a lowered third, lowered sixth and lowered seventh:
The lowered sixth and seventh have a stronger and more satisfying tendency to lead down to the tonic in descending melodies. Notice that the descending form is identical to the natural minor scale.
The complete C melodic minor scale is:
The Harmonic Minor Scale
The harmonic minor scale contains the lowered third, lowered sixth and natural seventh degrees of the source minor scale. It is the most common source for harmony (chords) in minor keys. The C harmonic minor scale is:
Other Minor Scales
By definition, there are at least two other minor scales: the Dorian mode and jazz minor (which is the same as ascending melodic minor in both directions).
Parallel and Relative Scales and Keys
There are two ways of describing the relationship between major and minor scales and keys: parallel and relative.
Major and minor keys and scales which have the same tonic (root) are in a parallel relationship. For example, a C minor scale (whether natural, melodic or harmonic) is the parallel minor of the C major scale. Conversely, C major is the parallel major of C minor.
Major and minor keys and scales which use the same key signature and notes, but which don’t have the same tonic, are relative. The relative natural minor scale of a major scale begins on the sixth degree of that scale. For example, the sixth note of the C major scale is A, so the relative natural minor of C major is A minor. The A natural minor scale uses exactly the same notes as C major (all white keys).
The relative major scale of a natural minor scale begins on the third degree of that scale. For example, the third note of the G natural minor scale is B-flat, so B-flat major is the relative major of G minor.
Diatonic Minor Triads
Since the source minor scale contains two possibilities for the sixth and seventh scale degrees, there are more triads possible in minor than in major. Nonetheless, there are seven triads that occur most frequently:
Notice that the roots of these triads come from the harmonic minor scale.
Diatonic Minor Tetrads
Like the triads, there are more tetrads or “seven chords” that can be derived from the source minor scale than from the major scale. These seven are the most common:
Notice that all of the roots and most of the other tones in these chords belong to the harmonic minor scale.