MUTC 202/206 help sheet on diatonic modes

Diatonic Modes are analogous to scales. Both modes and scales consist of ordered sequences of 7 pitches (not counting the octave!) with set patterns of half steps and whole steps.

Consider how the C major scale and the A natural minor scale are basically different rotations of each other. While they do sound alike (having the same overall pitches), they also sound different when we are oriented toward their tonic or (in modal terms) ‘final.’ That is, A minor sounds distinctly different from C major. This is because the intervallic structures of the scales are different. In other words, the half steps and whole steps are in different places.

C major: C D E F G A B (C) W W H W W W H

A natural A B C D E F G (A) minor W H W W H W W

Still, it is important to note that each scale has 7 notes, and only two half steps. Moreover, the half steps are separated by two whole steps on one side, and three whole steps on the other.

A simple way of describing the relationship between these scales is to say that each is a rotation of the other. More specifically, we can say that the C major scale and the A natural minor scale are different modes of the same diatonic collection (the diatonic collection commonly known as “C major,” or the “white-key collection”).

Below are ascending versions of all seven modes of the “white-key diatonic collection.”

Mode IC Ionian: C D E F G A B (C)(major) W W H W W W H

Mode IID Dorian: D E F G A B C (D)

W H W W W H W

Mode IIIE Phrygian: E F G A B C D (E)

H W W W H W W

Mode IVF Lydian: F G A B C D E (F)

W W W H W W H

Mode VG Mixolydian: G A B C D E F G

W W H W W H W

Mode VIA Aeolian: A B C D E F G A(nat. minor) W H W W H W W

Mode VIIB Locrian: B C D E F G A B(rare) H W W H W W W

Before the 1600’s, compositional music (sacred or secular) was ‘modal.’ During the Baroque era (ca. 1600-1750) trends in composition began to favor the major and minor modes more exclusively. Composers in the twentieth century such as Debussy, Bartók, Shostakovich, Fauré, Janacek, and Martinu used other rotations, or modes of diatonic collections. In doing so, they were able to use familiar materials (by continuing to use diatonic collections with recurrent patterns of half and whole steps) but in different ways (by composing with rarely-used rotations of those collections). Furthermore, the resurgence of diatonic modes evoked the distant past (although modes would have sounded much different then, as equal temperament had not been developed), which gave compositions even more caché.

Composers used modes from other familiar collections. Most notably, the ascending form of the melodic minor scale offered some modes that were perennial favorites of Eastern European composers such as Bartók, Martinu, and Janacek.

Here are two popular modes of the ascending melodic minor collection. These modes come from the collection that begins on C (C-D-Eb-F-G-A-B-C)

Mode IVF Mixolydian raised 4 F G A B C D Eb F

W W W H W H W

Mode VG Mixolydian lowered 6 G A B C D Eb F G

W W H W H W W