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Music Theory: Lesson 8

The Diatonic Chords

By Zack Cart

 

Prerequisites:

You should be able to understand and perform the concepts and techniques outlined in the following lessons before attempting this lesson:

Music Theory: Lessons 1-7

 

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In the previous lesson, we explored chords and their voicings, in this lesson, we will examine the most basic way in which chords fit together- the diatonic system. In this context, “diatonic” will essentially be used to mean “scale-related,” or essentially, key-related.

 

Each key has a series of seven basic triads which can be built from its notes. These chords are quite simple to derive. There is one triad for each note of the key, or scale, in other words, one chords which derives its letter name from each note.

 

For a given letter name in a key, all that is required to determine the type of triad which it is, is to choose the note a third above it in the scale, and the note a third above that note. (Or a fifth above the starting note)

The thirds used here will be either major or minor, and will vary depending on the scale. For example, a third above C, in the key of C major would be E, while a third above E would be G. In the first case, we find a major third, in the second, a minor. If this is confusing, spend some more time with the previous Theory lessons, and become more comfortable with that material.

The important thing to remember here, is that ALL notes used must be from the same key, so the thirds will be determined reliant on the key signature.

 

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Let us begin with the key of C major. The notes, as a reminder, are C, D, E, F, G, A, and B.

 

To determine what kind of C chord is found in the key, we merely take C, the note a third above it in the scale, E; and the note a third above that, or a fifth above C, which is G. We then have the notes C, E, and G. If we refer back to Lesson 6, we find that this gives us a Tonic, C; Major third, E; and Perfect Fifth, G, resulting in a major chord, C major.

 

If we repeat the process beginning on the second degree, D, we take the notes D, up a third to F, and up a third to A. D is the tonic, F a minor third, and A a perfect fifth. The chord is D minor.

 

With the third degree, E, we take E, G, and B, and get E minor.

 

For the fourth degree, F, we must remember that the scale repeats indefinitely, so that above B is just another C, D, E, and so forth. Keeping this in mind, we get F, A, and C, creating an F Major chord.

 

We will find that the fifth degree, G, is a major chord; the sixth, A creates a minor chord, and that the B creates a diminished chord.

 

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If we repeat the process for the keys of Bb Major and A major, we discover something interesting in the following derived chords, when compared with the corresponding chords for each degree in C major.

Bb Major       C Major                  A Major

C minor                          D minor                  B minor

D minor                          E minor                   C# minor

Eb Major        F Major                  D Major

F Major                          G Major                  E Major

G minor                          A minor                  F# minor

A diminished                B diminished         G# diminished

 

Strangely enough, due to the consistent pattern of whole and half steps in each major scale, the chord types for each corresponding degree are identical in each key. This will hold true for every other Major key as well, so one need only learn the notes of each key, and the pattern of chord types to memorize the chords in each key.

Just in the interest of further clarification, below is a list of the chord type which can be built of each degree in a major scale.

Major

Minor

Minor

Major

Major

Minor

Diminished

 

And, while I encourage you to learn all the chords in each key by heart as well, I have provided a chart below which details all seven basic triads found in each of the standard keys. While this may be a very useful tool for learning the chords, try not to let this crutch become you norm, think of it instead as a stop-gap until you have a more complete memory of the notes and chords.

 

 

Major key	1st Scale Degree (Major)	2nd Scale Degree (Minor)	3rd Scale Degree (Minor)	4th Scale Degree (Major)	5th Scale Degree (Major)	6th Scale Degree (Minor)	7th Scale Degree (Diminished)
C	C	D	E	F	G	A	B
G	G	A	B	C	D	E	F#
D	D	E	F#	G	A	B	C#
A	A	B	C#	D	E	F#	G#
E	E	F#	G#	A	B	C#	D#
B	B	C#	D#	E	F#	G#	A#
F#	F#	G#	A#	B	C#	D#	E#
Gb	Gb	Ab	Bb	Cb	Db	Eb	F
Db	Db	Eb	F	Gb	Ab	Bb	C
Ab	Ab	Bb	C	Db	Eb	F	G
Eb	Eb	F	G	Ab	Bb	C	D
Bb	Bb	C	D	Eb	F	G	A
F	F	G	A	Bb	C	D	E