Musical mode

In music, a mode describes a particular diatonic scale.

Table of contents

1 History
2 The major and minor modes

2.1 Major Modes
2.2 Minor Modes

3 Learning the modes
4 Further Reading

History

The early music of Greek antiquity referred to scales in the context of scalar modes. The modes are named after cities that preferred a given mode in times past. The Greek philosopher Plato felt that playing music in a particular mode would incline one towards specific behavior associated with that mode, and suggested that soldiers should listen to music in dorian mode to help make them stronger, but avoid music in lydian mode, for fear of being softened.

There is a common misconception that the Church modes of medieval European music were directly descended from this notion of modality. In fact, the church modes originated in the 10th century. Authors from that period misinterpreted a text by Boethius, a scholar from the 6th century who had translated the Greek musical theory into Latin. In the 16th century, the Swiss theorist Henricus Glareanus published Dodekachordon, in which he solidified the concept of the church modes, and added four additional modes: the Aeolian, Hypoaeolian, Ionian, and Hypoionian. Thus, the names of the modes used today do not actually reflect those used by the Greeks.

Early music made heavy use of the Church modes, which were later organized due to their relationship to the interval pattern of the major scale. The modern conception of modal scales describes a system where each mode is the usual diatonic scale, but with a different starting note. Modes came back into favour some time later in the development of jazz (modal jazz) and more contemporary 20th century music. Much folk music is also best analysed in terms of modes. For example, in Irish traditional music the ionian, dorian, aeolian and mixolydian modes occur (in roughly decreasing order of frequency); the phrygian mode is an important part of the flamenco sound.

The major and minor modes

Three of the modes are major, while four of them are minor. One of the minor modes is considered theoretical rather than practical. A mode is said to be minor if the 3rd scale degree is flattened.

Major Modes

Lydian ()
Ionian ()
Mixolydian ()

Minor Modes

Dorian ()
Aeolian ()
Phrygian ()
Locrian (the theoretical mode) ()

Each mode has a characteristic scale degree and certain harmonic structures that give each its distinctive sound.

The Lydian mode has a raised fourth, which creates a iv diminished, vii minor, and a II major chord. The theme song from the TV show The Simpsons is written in the Lydian mode.
The Ionian mode has a V7 chord, and is the only mode where the V7 occurs naturally. Most common songs, including such simple classics as "Happy Birthday" and "Twinkle Twinkle Little Star," are in the Ionian mode.
The Mixolydian mode has a flat 7th degree; this creates a I7, a v minor, and a VII major chord. There is also a iii dim chord, but it is not used extensively in modal compositions. The Beatles song "Norwegian Wood" is in mixolydian mode.
The Dorian mode has a characteristic raised sixth, which produces a major IV chord and a minor II chord. "What shall we do with the drunken sailor" is in the Dorian mode.
The Aeolian mode has a flat six and seven; its characteristic chords are the minor iv and v chords. There is a subtle distinction between an Aeolian modal composition and a composition in a minor key, because the sixth and seventh degrees in a minor key can be altered to create major IV and V chords. (example...)
The Phrygian mode has a characteristic lowered second, which creates its characteristic bII major and v diminished chords. This mode is quite common in flamenco music and is often referred to as the "Spanish" mode.
The Locrian mode has a flat second and fifth scale degree and has a diminished i chord. It is highly unstable, and its diminished i chord makes establishing tonality in the mode nearly impossible. The few pieces have been written in this mode usually used an altered i minor chord to establish the tonal center, and then used the minor iii and major V chord to establish the modality. The locrian mode is so unstable that the bII chord cannot be used as it will quickly and inevitably establish itself as the I chord of a major key. The iv minor chord in second inversion with the tonic doubled is a good I chord for Locrian because it is the exact reverse of a major chord.

Learning the modes

You may work with the modes in a couple of ways.

If you're an instrumentalist, you may find the following approach useful to understanding the modal scales.

The Ionian mode is identical to the major scale of tonal music.
The Aeolian mode is identical to the natural minor scale of tonal music. Compared to Ionian, its 3rd, 6th, and 7th notes have been flattened.
Lydian is identical to Ionian, except that the 4th note in the scale is sharpened.
Mixolydian is identical to Ionian, exception that the 7th note in the scale is flattened.
Dorian is identical to Aeolian, except its 6th scale degree is sharpened.
Phrygian is identical to Aeolian, except its 2nd scale degree is lowered.
Locrian, the theoretical mode, is identical to Aeolian, except its 2nd and 5th scale degrees are flattened. Because its 5th scale degree is flattened, this mode sounds very unstable, and isn't generally used for melodies.

Using this technique, one may apply a simple bit of mathematics towards converting from one mode to another. First, one should memorize the number of flats and sharps for all Ionian scales (e.g. F ionian has 1 flat). One should also memorize how to notate the flats and sharps on a musical bar. Then, one should memorize this chart:

Lydian: +1
Ionian: 0
Mixolydian: -1
Dorian: -2
Aeolian: -3
Phrygian: -4
Locrian: -5

If you think of flats as negative numbers and sharps as positive numbers, you may use simple mathematics to convert between modes. For example, having memorized that the C major/ionian scale has zero sharps or flats, and wanting to know what notes C phrygian should change, you would add 0 to phrygian's -4 to get -4.. meaning four flats. So C phrygian has four flats, (B, E, A, and D).

Or, for a slightly more complicated example, try figuring out F locrian:

F major/ionian has 1 flat, so it's -1. Locrian has a -5, so -1 + -5 is -6. Therefore, F locrian has six flats (B, E, A, D, G, and C).

If you work with keyboard instruments, you may find the following technique more useful in working with modes.

If you're familiar with your major scales, each modal scale may be thought of as starting at a different scale degree from the major scale.

Thus, you may memorize which scale degree to start at for each mode.

Lydian: IV
Ionian: I
Mixolydian: V
Dorian: II
Aeolian: VI
Phrygian: III
Locrian: VII

The patterns of tones (T) and semitones (S) are as follows:

TTTsTTs Lydian TTsTTTs Ionian (modern major) TTsTTsT Myxolydian 
TsTTTsT Dorian TsTTsTT Aeolian (modern minor) sTTTsTT Phrygian sTTsTTT Locrian

Note the shifts of alternate semitones from row to row.

Each of these modes has a unique scale without any sharps or flats. They are as follows:

Lydian F Ionian C major Myxolydian G Dorian D Aeolian A minor Phrygian E Locrian B