Chapter 18:

Diatonic modes

What are diatonic modes?

The diatonic modes are the seven rotations of the major scale, each starting at a different degree of the major scale and wrapping around the end to the beginning.

For example, the first mode of C major has the notes C-D-E-F-G-A-B-C. The second mode of C major has the notes D-E-F-G-A-B-C-D, and the third mode E-F-G-A-B-C-D-E.

While the different modes have the same notes, they have a different note as the 1̂, which changes the tonal center and all the scale degree intervals, since they are measured from the 1̂. This gives each mode a different sound and feel.

Each mode is intimately linked to the corresponding chord in the harmonized major scale. For example, the second mode is the scale that underlies the ii chord, and the fifth mode is the scale under the V chord. The sound and feel of each mode is the sound and feel of the corresponding chord.

Diatonic modes are named with obscure Greek-related terms that make little sense and just have to be memorized. Starting with the first degree of the major scale, the diatonic modes are (1) Ionian, (2) Dorian, (3) Phrygian, (4) Lydian, (5) Mixolydian, (6) Aeolian, and (7) Locrian.

A mnemonic to help remember the modes is “I Don’t Punch Like Mohammed A-Li”.

Modes of the major scale

Reference modes

A simple way to get familiar with modes is to first determine if they are major or minor (having a 3̂ or b3̂) and then compare them to a major or minor “reference mode”.

Ionian, the major scale, is the major reference mode.

Aeolian, the natural minor scale, is the minor reference mode.

Each of the other modes differs from Ionian or Aeolian by only a single interval (except the dissonant Locrian, which flattens every Ionian interval but one). This single interval difference creates the mode’s unique sound and feel.

We can focus on these small differences to summarize the mode in our mind. For example, it’s much easier to remember that Phrygian is “a minor with a b2” rather than that it has scale degrees 1-b2-b3-4-5-b6-b7.

This is an example of the memory technique “chunking”. By learning the natural minor mode well, it becomes one “chunk”. We can then learn other minor modes as “minor with one difference”, essentially holding two “chunks” in memory to define Phrygian (“minor” and “b2”), rather than seven “chunks” (1-b2-b3-4-5-b6-b7).

See “How to learn” in the Introduction for details.

I: Ionian - major

The Ionian mode is the major scale.

It describes the harmonic environment of the I chord.

As the major scale, it’s the ultimate reference mode. All scales in Western music are implicitly compared against this mode, because it describes every major and perfect interval. The minor intervals are then found one fret below them.

Compare any tetrachord to this mode to quickly identify the intervals of its scale degrees.

The Ionian mode should be memorized. It allows us to immediately identify the interval between any two notes up to an octave apart on the fretboard.

vi: Aeolian - minor

The Aeolian mode is the natural minor scale.

It describes the harmonic environment of the vi chord (or the i chord in a minor key).

Aeolian, natural minor, has a b3, b6, and b7, compared to the Ionian mode.

The b3 is the sound of a minor mode.

The b7 is a whole tone below the tonic rather than being a leading tone. The absence of a leading tone is the cause of all the mischief with harmonic and melodic minor scales. See Chapter 17. Minor scales for details.

To get familiar with the sound of the Aeolian mode, play a vi chord in a major key, then starting from the root note of the vi chord, 6̂, continue the major scale up to the 6̂ an octave above, 6-7-1-2-3-4-5-6 (remembering the semitone between 3-4 and 7-1), and then play another vi chord. Improvise for awhile within those notes, making a point of dwelling on the 6̂ as “home”.

Assembling modes in this way is easier than memorizing the shapes of all the modes on the fretboard. We just have to memorize the major scale and the Ionian tetrachord.

Compare the assembled tetrachords to Ionian to quickly identify the intervals.

To compare the sound of this mode to others in the key of C major, play an Am chord with its root on the open 5th string, assemble the tetrachord on the 5th and 6th strings starting from the root of the chord, and then play another Am.

ii: Dorian

The Dorian mode describes the harmonic environment of the ii chord.

Dorian is the only diatonic minor mode with a natural 6.

To get familiar with the sound of this mode, play a ii chord, then play the parent major scale starting from the chord root to the octave above it, 2-3-4-5-6-7-1-2 (remembering the semitone between 3-4 and 7-1), and then play another ii chord. Improvise for awhile within those notes, dwelling on the 2̂ as “home”.

Pay particular attention to the unique sound of the natural 6 in this mode. It’s the 7̂ degree of the parent major key. In D Dorian (the second mode of C major), it’s the B note. This sound is the defining characteristic of the Dorian mode.

To compare the sound of this mode to others in the key of C major, play a Dm chord with its root on the 5th string 5th fret, assemble the tetrachord on the 5th and 6th strings starting from the root of the chord, and then play another Dm.

iii: Phrygian

The Phrygian mode describes the harmonic environment of the iii chord.

Phrygian is a diatonic minor mode with a b2.

The b2 interval tends to sound “foreign” to Western ears, vaguely Arabic or Spanish.

To get familiar with the sound of this mode, play a iii chord, then play the parent major scale starting from the chord root to the octave above it, 3-4-5-6-7-1-2-3 (remembering the semitone between 3-4 and 7-1), and then play another iii chord. Improvise for awhile within those notes, dwelling on the 3̂ as “home”.

Pay particular attention to the unique sound of the b2 in this mode. It’s the 4̂ degree of the parent major key. In E Phrygian (the third mode of C major), it’s the F note. This sound is the defining characteristic of the Phrygian mode.

To compare the sound of this mode to others in the key of C major, play an Em chord with its root on the 5th string 7th fret, assemble the tetrachord on the 5th and 6th strings starting from the root of the chord, and then play another Em.

IV: Lydian

The Lydian mode describes the harmonic environment of the IV chord.

Lydian is the only diatonic major mode with a #4.

The #4 is a tritone, enharmonic with the b5 which is well-known as a dissonant tone. But sometimes, as in Lydian, it can evoke a brighter and dreamier sound.

To get familiar with the sound of this mode, play a IV chord, then play the parent major scale starting from the chord root to the octave above it, 4-5-6-7-1-2-3-4 (remembering the semitone between 3-4 and 7-1), and then play another IV chord. Improvise for awhile within those notes, dwelling on the 4̂ as “home”.

Pay particular attention to the unique sound of the #4 in this mode. It’s the 7̂ degree of the parent major key. In F Lydian (the fourth mode of C major), it’s the B note. This sound is the defining characteristic of the Lydian mode.

To compare the sound of this mode to others in the key of C major, play an F chord with its root on the 5th string 8th fret, assemble the tetrachord on the 5th and 6th strings starting from the root of the chord, and then play another F.

V: Mixolydian

The Mixolydian mode describes the harmonic environment of the V chord.

Mixolydian is the only diatonic major mode with a b7.

The b7 interval is kind of a gritty sound. It is common in blues, and well-known as a way to add dissonance to a chord. The interval between the major 3̂ and the b7̂ is a tritone, and the basic sound of a dominant 7 chord.

To get familiar with the sound of this mode, play a V chord, then play the parent major scale starting from the chord root to the octave above it, 5-6-7-1-2-3-4-5 (remembering the semitone between 3-4 and 7-1), and then play another V chord. Improvise for awhile within those notes, dwelling on the 5̂ as “home”.

Pay particular attention to the unique sound of the b7 in this mode. It’s the 4̂ degree of the parent major key. In G Mixolydian (the fifth mode of C major), it’s the F note. This sound is the defining characteristic of the Mixolydian mode.

To compare the sound of this mode to others in the key of C major, play an F chord with its root on the 5th string 8th fret, assemble the tetrachord on the 5th and 6th strings starting from the root of the chord, and then play another F.

vii: Locrian

The Locrian mode describes the harmonic environment of the vii chord.

Compared to Ionian, in Locrian every degree is flattened but the 4̂. It’s also the only diatonic minor mode with a b5.

Locrian is a disagreeable sort of mode. It’s rumored to be popular among heavy metal guitarists because of its dissonance, but examples are hard to find.

To get familiar with the sound of this mode, play a vii chord, then play the parent major scale starting from the chord root to the octave above it, 7-1-2-3-4-5-6-7 (remembering the semitone between 3-4 and 7-1), and then play another vii chord. Improvise for awhile within those notes, dwelling on the 7̂ as “home”.

To compare the sound of this mode to others in the key of C major, play a Bdim chord with its root on the 5th string 2nd fret, assemble the tetrachord on the 5th and 6th strings starting from the root of the chord, and then play another Bdim.