Modal Harmony

Some Basics of Modal Harmony

(Copyright 1995 Roger W. Landes. Revised July 1997.)

Nearly everyone is familiar with the major and minor scales used in western music, but less common is the knowledge that these scales are but two of an older system of natural modes which dates from antiquity. The natural modes are: Ionian, Dorian, Phrygian, Lydian, Mixolydian, Aeolian and Locrian These modes are known by Greek names since they were first recorded in Ancient Greece. The names reputedly correspond to different regions or cities where they originated. In Western music, the distance between two pitches, or frequencies, in 1:2 proportion is called an octave. This is the point at which the frequency, expressed in Hertz, or vibrations per second, is doubled. For instance, the distance between the common pitch standard A=440hz, and A=880hz, is an octave. This is also the point at which the names of the notes begin to repeat. The octave is divided into 12 equal steps and the distance of each step is called an interval. The difference in frequency between each of these notes is roughly equal and the sequence of these makes up the chromatic scale. (On the piano, the chromatic scale corresponds to every white and black key between two notes which have the same name. On the guitar and other fretted instruments, the chromatic scale corresponds to each successive fret on one string between two notes of the same name. In each case the number of keys or frets in the octave is 12.) The Chromatic Scale: C C# D D# E F F# G G# A A# B (The next note in this sequence is C, then the cycle repeats.) 1 2 3 4 5 6 7 8 9 10 11 12 The note sequence which makes up a scale is like a ladder with each note of the scale corresponding to a rung on the ladder. With the chromatic scale the intervals between each of the notes is referred to as a half step. Two half steps (C to D) = a whole step. With the Major and Minor scales, which span the octave in only seven notes, the intervals between the notes are not equal, that is, the interval between each note is either a half or whole step, and the sequence is different for each of the modes. This intervallic difference is what gives each scale its own unique character. Intervals of varying distance have different names: In any scale the distance between the first and second notes is called a 2nd; between the first and third notes a 3rd; first and fourth a 4th; first and fifth a 5th; first and sixth a 6th; first and seventh a 7 th ; the first and eighth an octave. Since Ionian is the "Major" mode, the names of the intervals which reflect its “major” character: the 3rd, 6th, and 7 th, are Major intervals. A Major 3rd is the interval between the 1 st and 3rd notes of the scale, a distance of 2 whole steps (4 frets -- D to F#). A Major 6th is between the 1 st and 6th notes, and is 4½ half steps (9 frets -- D to B). A Major 7th is between the 1st and 7th notes, 5½ steps (11 frets -- D to C#). In the Aeolian (or minor) mode the 3rd, 6th, and 7th are “minor” intervals. Minor intervals are one half step lower than Major intervals, so the 3rd is 1½ steps (3 frets) above the first note of the scale; the 6th is 4 steps (8 frets) above; and the 7th is 5 steps (10 frets) above. The intervals between the 1st & 4th and 1st & 5th notes of both scales are called perfect intervals, and if lowered 1/2 step become diminished. The interval between the 1 st & 2nd notes is usually referred to as a Major interval, and if lowered by 1/2 step becomes minor (this has no bearing on whether mode is minor or major – the second interval is Major in all four of the modes covered in this paper).

Deriving the Natural Modes from the Major Scale: The other natural modes can each be derived from the Major scale, or Ionian mode, by beginning a sequence of seven notes on a different note of the Ionian mode. Using D as a key center for the Ionian mode (DEF#GABC#) we get the Dorian mode by starting on the 2nd note, E, for the sequence (EF#GABC#D), Phrygian by starting on the 3rd (F#GABC#DE), Lydian on the 4th (GABC#DEF#G), Mixolydian on the 5th (ABC#DEF#G), Aeolian on the 6th (BC#DEF#GA), and Locrian on the 7th (C#DEF#GABC). Of these seven modes only four: Ionian (major), Dorian, Mixolydian, and Aeolian (minor), are used with any frequency in Irish or Scots traditional music. By approaching these four modes (and learning the chords which are inherent in each) we can increase our choices for harmonizing traditional music on any accompaniment instrument. We'll do this by a technique called "harmonizing the scale," which involves combining the notes of each scale in groups three, called triads. Triads are the basic building blocks of Western harmony.

Notes in each of the natural modes: I. II. III. IV. V. VI. VII.

Ionian DEF#GABC# Dorian EF#GABC#D Phrygian F#GABC#DE Lydian GABC#DEF# Mixolydian ABC#DEF#G Aeolian BC#DEF#GA Locrian C#DEF#GAB

Harmonizing the modes common in Celtic music: Each note of the scale has a corresponding number which is usually expressed in Roman numerals: I-VII. In "D" Ionian they are: D I, E II, F# III, G IV, A V, B VI, and C# VII. If we select three notes each a note apart, such as D, F#, & A, and "stack" them on top of each other, we get a basic three note chord called a "triad." Applying this concept to each note of the "D" Ionian mode we get: T R I A D

A B C# F# G A D E F# 1 2 3 SCALE

D B G 4

E C# A 5

F# D B 6

G E C# 7

Each of these triads has a name: I. II. III. IV. V. VI. VII.

D Major -- DF#A E minor -- EGB F# minor -- F#AC# G Major -- GBD A Major -- AC#E B minor -- BDF# C# diminished -- C#EG

This sequence of Major, minor, and diminished triads never varies for the Ionian (Major) mode.

For the 2nd mode, E Dorian, the sequence of triads is: T R I A D

B C# G A E F# 1 2 SCALE

D B G 3

E F# C# D A B 4 5

G E C# 6

A F# D 7

These are: I. II. III. IV. V. VI. VII.

E minor -- EGB F# minor -- F#AC# G Major -- GBD A Major -- AC#E B minor -- BDF# C# dim. -- C#EG D Major -- DF#A

This sequence of triads never varies for the Dorian mode, and differs from the harmonized D Ionian mode only in that it begins on the 2nd note of the Ionian mode, E, and the D major triad which was the first, or "I" chord in Ionian, becomes "VII" in Dorian.

For the Mixolydian, or 5th mode, the sequence of triads is: T R I A D

E F# C# D A B 1 2 SCALE

G E C# 3

A F# D 4

B G E 5

C# A F# 6

D B G 7

These are: I. II. III. IV. V. VI. VII.

A Major -- AC#E B minor -- BDF# C# diminished -- C#EG D Major -- DF#A E minor -- EGB F# minor -- F#AC# G Major -- GBD

This sequence of Major, minor, and diminished triads never varies for the Mixolydian mode, and differs from the Ionian and Dorian modes in that it begins on the 5th note of the Ionian mode, and the A Major chord, which was the "V"

For the Aeolian, or 6th mode, the sequence of triads is: T R I A D

F# G D E B C# 1 2 SCALE

A F# D 3

B G E 4

C# A F# 5

D B G 6

E C# A 7

These are: I. II. III. IV. V. VI. VII.

B minor -- BDF# C# diminished -- C#EG D Major -- DF#A E minor -- EGB F# minor -- F#AC# G Major -- GBD A Major -- AC#E

Again, this sequence doesn't vary, and it differs from the Ionian, Dorian, and Mixolydian modes in that it begins on the 6th note of the Ionian scale. It is important to note that since the notes of E Dorian, A Mixolydian, and B Aeolian are the same as D Ionian, the chords will always be the same but each will have a very different function when applied in each of the four key centers. If we learn the sequence of Major, minor, and diminished triads for these four modes, we'll be able to apply them in any key center. For instance, since we know that the "II" chord, or triad in D Ionian is E minor, then we can find the correct chord in G -- II is A minor, C -- II is D minor, A -- II is B minor, E -- II is F# minor, and so on. We can do the same thing with the "VI" chord. We know that in D Ionian it is B minor, so in G -VI is E minor, C -- VI is A minor, A -- VI is F# minor, E -- VI is C# minor.

Exercises: Write the scales below and harmonize them. (Hint: each group of four modes bears the same relationship to each other as D Ionian, E Dorian, A Mixolydian, and B Aeolian.) 1. G Ionian

_____________________ 1 2 3 4 5 6 7

2. A Dorian

_____________________ 1 2 3 4 5 6 7

3. D Mixolydian _____________________ 1 2 3 4 5 6 7

4. E Aeolian

_____________________ 1 2 3 4 5 6 7 Next, write the scales below and harmonize them:

1 C Ionian

______________________ 1 2 3 4 5 6 7

2. D Dorian

______________________ 1 2 3 4 5 6 7

3. G Mixolydian _____________________ 1 2 3 4 5 6 7

4. A Aeolian

_____________________ 1 2 3 4 5 6 7

Next:

1. A Ionian

_____________________ 1 2 3 4 5 6 7

2. B Dorian

_____________________ 1 2 3 4 5 6 7

3. E Mixolydian _____________________ 1 2 3 4 5 6 7

4. F# Aeolian

_____________________ 1 2 3 4 5 6 7

Roger Landes is an accomplished player and teacher of the Irish Bouzouki. He regularly appears in concert with singer Connie Dover, accordionist John Whelan, and ace accompanist Zan McLeod. He has a solo album of tunes played on his 10string Bouzouki. You can read more about Roger & his musical pursuits online at http://www.celticmusic.com/roger_landes

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