We have looked at the construction of the major and melodic minor scales in the previous articles of this Beginning Jazz Theory series.

Harmonizing these scales will take us into a more musical sounding aspect of the theory behind the jazz sound.

Let’s see which chords and why, are used within each of the major and minor scales we have looked at.

Then, we will actually play a common chord progression in jazz that may surprise you with the easy logic behind this famous progression.

Applying Scale Degrees to the Major Scale

We discussed in our first article how the major scale (diatonic) consists of whole and half steps (W-W-h-W-W-W-h).

Diatonic simply means the seven note scales that formulate the whole and half step system.  (Versus a chromatic scale that uses all 12 notes (all white and black keys of a piano octave for instance).

The whole and half step formula describes the spacing of the scale, but now we will number each note.

Each note in a scale has a specific scale degree.

The usefulness of scale degrees is crucial to musical concepts such as harmonizing a note and using chord progressions.

C Major Diatonic Scale

Note

C

D

E

F

G

A

B

Scale Degree

I

ii

iii

IV

V

vi

vii

Root

2

3

4

5

6

7

Scale degrees expressed in Roman numerals in Western musical tradition (Western vs. the Orient for example) are common.

You may have noticed in the above C major scale that C is the root note or the first degree of that scale.

This is the note or sound that this scale revolves around and will resolve to that same sound (C) for a feeling of completion.

When looking at a piece of music, we can see the Key of the song may be stated as C major (CM) in the key signature.  In basic compositions, that is the root or the foundation the sound revolves around.

Harmonizing the Major Diatonic Scale

Each scale degree (number) can also identify the corresponding chord.

A note in a scale harmonized with a seventh chord has a certain quality which identifies how that chord sounds, such as CM7 versus just CM.

Here are the seventh chords that harmonize the CM scale.

C Major Diatonic Seventh Chords

Note

C

D

E

F

G

A

B

Quality

Maj 7

min 7

min 7

Maj 7

Dom 7

min 7

Half dim

Chord

CMaj7

Dmin7

Emin7

FMaj7

GDom7

Amin7

Bmin7(b5)

Scale Degree

I

ii

iii

IV

V

vii

vii

CM7

Dm7

Em7

FM7

G7

Am7

Bø7

M=Major
m=minor
ø=half diminished
Dom=Dominant 7 (indicated as G7, for example)

Notice there are three major 7 chords (including G Dominant) and the rest have a minor quality.  The major chords have capital Roman numerals.

It should be noted that a minor 7 flat 5 quality is called a half diminished chord, often denoted with a circle and a slash through it, for example Bø7.  Fortunately, it only appears intimidating in print but not when you play it.

Let’s harmonize the D Major diatonic scale to compare the formula against the CM scale.

D Major Diatonic Seventh Chords

Note

D

E

F#

G

A

B

C#

Quality

Maj 7

min 7

min 7

Maj 7

Dom 7

min 7

Half dim

Chord

DMaj7

Emin7

F#min7

GMaj7

ADom7

Bmin7

C#min7(b5)

Scale Degree

I

ii

iii

IV

V

vii

vii

DM7

Em7

F#m7

GM7

A7

Bm7

C#ø7

Note: the 5th scale degree is always a dominant chord in the major scale.

Notice that the 1st (root), 4th and 5th scale degrees have identical qualities as the C major scale we looked at earlier, as do all the other major scales.

The quality of chords within a specific scale will remain the same up to and including the 7th regardless of the key, but extended chords will add 9th, 11th and 13th notes beyond the seventh, creating even richer sounding chords than the seventh. 

This is a formula based on quality (indicated in above table) for the major scale that can assist us in applying the correct sounding chord where needed.

Without indicating the dominant and half diminished, we can simplify the formula for memory purposes to: Major-minor-minor-Major-Major-minor-minor, remembering that the 5th is always dominant and the 7th half diminished when in the major scale.

Harmonizing the Melodic Minor Scale

Notice the chord formula as depicted by quality below.

C Minor Diatonic Seventh Chords

Note

C

D

Eb

F

G

A

B

Quality

min 7

min 7

Maj 7#5

Dom 7

Dom 7

Half dim

Dom 7

Chord

Cmin7

Dmin7

EbMaj7#5

FDom7

GDom7

A half dim

BDom7

Scale Degree

I

ii

iii

IV

V

vii

vii

Cm7

Dm7

EbM7#5

F7

G7

Aø7

B7

Notice that the 5th scale degree stays a dominant chord as in the major scale.  This is because the 5th degree must always be dominant.

As you progress in your music theory you may come across the fact that the minor scale is difficult to harmonize perfectly as it must borrow from the other minor scales (melodic, natural and harmonic) in order to sound correct.

Chord Progressions

We now know the scale degrees and the harmonized chords that go with them.

One of the most common chord progressions in jazz is the 2-5-1.

Take for example a 2-5-1 in the key of C major.

C Major

Note

C

D

E

F

G

A

B

Chord

CM7

Dm7

Em7

FM7

G7

Am7

Bø7

Scale Degree

I

ii

iii

IV

V

vii

vii

Notice the highlighted scale degrees for the 2, 5, 1 and the accompanying chords.

The 2-5-1 chord progression means you start by playing the 2nd chord (Dm7), then the 5th (G7) and finally resolve to the 1st or root chord of CM7.  Try it on your instrument.

Here are some chord diagrams for the guitar.

The more you become familiar with playing the harmonized chords of a key, the more you will begin to feel the qualities of each chord whereby the root chord can be considered as home and the further you roam from “home”, the more you wish to resolve the aural need to finish up on the root.

In particular the dominant 5th chord is famous for the yearning feeling of wanting to get home to the root, thereby resulting in a big satisfying finish to your song.

Summary

In this article we have reviewed:

  • Scale degrees
  • The harmonization of each scale degree
  • Chord qualities
  • Chord progressions

There are many more scales and chord progressions for you to explore, so have fun.

I hope you enjoyed these articles and that they have helped in some way.



About the author: Robert Weeks is a jazz music enthusiast and guitar player from British Columbia, Canada.

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