In music theory, the minor scale is three scale patterns – the natural minor scale (or Aeolian mode), the harmonic minor scale, and the melodic minor scale (ascending or descending) – mirroring the major scale, with its harmonic and melodic forms
In each of these scales, the first, third, and fifth scale degrees form a minor triad (rather than a major triad, as in a major scale). In some contexts, minor scale is used to refer to any heptatonic scale with this property (see Related modes below).
A natural minor scale (or Aeolian mode) is a diatonic scale that is built by starting on the sixth degree of its relative major scale. For instance, the A natural minor scale can be built by starting on the 6th degree of the C major scale:
Because of this, the key of A minor is called the relative minor of C major. Every major key has a relative minor, which starts on the 6th scale degree or step. For instance, since the 6th degree of F major is D, the relative minor of F major is D minor.
A natural minor scale can also be constructed by altering a major scale with accidentals. In this way, a natural minor scale is represented by the following notation:
This notation is based on the major scale, and represents each degree (each note in the scale) by a number, starting with the tonic (the first, lowest note of the scale). By making use of flat symbols (♭) this notation thus represents notes by how they deviate from the notes in the major scale. Because of this, we say that a number without a flat represents a major (or perfect) interval, while a number with a flat represents a minor interval. In this example, the numbers mean:
Thus, for instance, the A natural minor scale can be built by lowering the third, sixth, and seventh degrees of the A major scale by one semitone:
Because they share the same tonic note of A, the key of A minor is called the parallel minor of A major.
The intervals between the notes of a natural minor scale follow the sequence below:
where "whole" stands for a whole tone (a red u-shaped curve in the figure), and "half" stands for a semitone (a red angled line in the figure).
The natural minor scale is maximally even.
Main article: Harmonic minor scale
The harmonic minor scale (or Aeolian ♯7 scale) has the same notes as the natural minor scale except that the seventh degree is raised by one semitone, creating an augmented second between the sixth and seventh degrees.
Thus, a harmonic minor scale is represented by the following notation:
A harmonic minor scale can be built by lowering the 3rd and 6th degrees of the parallel major scale by one semitone.
Because of this construction, the 7th degree of the harmonic minor scale functions as a leading tone to the tonic because it is a semitone lower than the tonic, rather than a whole tone lower than the tonic as it is in natural minor scales.
The intervals between the notes of a harmonic minor scale follow the sequence below:
While it evolved primarily as a basis for chords, the harmonic minor with its augmented second is sometimes used melodically. Instances can be found in Mozart, Beethoven (for example, the finale of his String Quartet No. 14), and Schubert (for example, in the first movement of the Death and the Maiden Quartet). In this role, it is used while descending far more often than while ascending. A familiar example of the descending scale is heard in a Ring of bells. A ring of twelve is sometimes augmented with a 5♯ and 6♭ to make a 10 note harmonic minor scale from bell 2 to bell 11 (for example, Worcester Cathedral).
The Hungarian minor scale is similar to the harmonic minor scale but with a raised 4th degree. This scale is sometimes also referred to as "Gypsy Run", or alternatively "Egyptian Minor Scale", as mentioned by Miles Davis who describes it in his autobiography as "something that I'd learned at Juilliard".
In popular music, examples of songs in harmonic minor include Katy B's "Easy Please Me", Bobby Brown's "My Prerogative", and Jazmine Sullivan's "Bust Your Windows". The scale also had a notable influence on heavy metal, spawning a sub-genre known as neoclassical metal, with guitarists such as Chuck Schuldiner, Yngwie Malmsteen, Ritchie Blackmore, and Randy Rhoads employing it in their music.
Further information: Jazz minor scale
The distinctive sound of the harmonic minor scale comes from the augmented second between its sixth and seventh scale degrees. While some composers have used this interval to advantage in melodic composition, others felt it to be an awkward leap, particularly in vocal music, and preferred a whole step between these scale degrees for smooth melody writing. To eliminate the augmented second, these composers either raised the sixth degree by a semitone or lowered the seventh by a semitone.
The melodic minor scale is formed by using both of these solutions. In particular, the raised sixth appears in the ascending form of the scale, while the lowered seventh appears in the descending form of the scale. Traditionally, these two forms are referred to as:
The ascending and descending forms of the A melodic minor scale are shown below:
The ascending melodic minor scale can be notated as
while the descending melodic minor scale is
Using these notations, the two melodic minor scales can be built by altering the parallel major scale.
The intervals between the notes of an ascending melodic minor scale follow the sequence below:
The intervals between the notes of a descending melodic minor scale are the same as those of a descending natural minor scale.
Composers have not been consistent in using the two forms of the melodic minor scale. Composers frequently require the lowered 7th degree found in the natural minor in order to avoid the augmented triad (III+) that arises in the ascending form of the scale.
Examples of the use of melodic minor in rock and popular music include Elton John's "Sorry Seems to Be the Hardest Word", which makes, "a nod to the common practice... by the use of F♯ [the leading tone in G minor] as the penultimate note of the final cadence." The Beatles' "Yesterday" also partly uses the melodic minor scale.
In modern notation, the key signature for music in a minor key is typically based on the accidentals of the natural minor scale, not on those of the harmonic or melodic minor scales. For example, a piece in E minor will have one sharp in its key signature because the E natural minor scale has one sharp (F♯).
Major and minor keys that share the same key signature are relative to each other. For instance, F major is the relative major of D minor since both have key signatures with one flat. Since the natural minor scale is built on the 6th degree of the major scale, the tonic of the relative minor is a major sixth above the tonic of the major scale. For instance, B minor is the relative minor of D major because the note B is a major sixth above D. As a result, the key signatures of B minor and D major both have two sharps (F♯ and C♯).
Sometimes scales whose root, third, and fifth degrees form a minor triad are considered "minor scales". In the Western system, derived from the Greek modes, the principal scale that includes the minor third is the Aeolian mode (the natural minor scale), with the minor third also occurring in the Dorian mode and the Phrygian mode. The Dorian mode is a minor mode with a major sixth, while the Phrygian mode is a minor mode with a minor second. The Locrian mode (which is very rarely used) has a minor third but not the perfect fifth, so its root chord is a diminished triad.
Although various hemitonic[clarification needed] pentatonic scales might be called minor, the term is most commonly applied to the relative minor pentatonic scale, derived as a mode of the major pentatonic scale, using scale tones 1, 3, 4, 5, and 7 of the natural minor scale.