18. Major Diatonic Chords as Four-Note Chords

Major Diatonic Chords as Four-Note Chords

Last time, we learned the major diatonic chords as triads.
Now, seven chords can be used in each major key.

This time, by learning the major diatonic chords as four-note chords, you'll have even more chords available and can broaden your range of expression.
(When composing, of course, it's fine to mix triads and four-note chords.)

These four-note major diatonic chords are completed with a small modification to last time's triads.
As in the previous section, the key point is that they are the chords that can basically be used within a particular key.
For example, if the key is C major, you use chords made only of notes from the C major scale.

Review of the Four Types of Seventh Chords

Let's briefly review the four types of seventh chords we've covered so far.

• Major seventh
• Minor seventh
• Dominant seventh
• Minor seventh flat five

If you're unsure, review them at the links above.

As last time, let's think along the steps of writing a song.
For example, suppose you want to write a song in the key of C major.

In that case, you basically write the melody with notes from the C major scale.

We've prepared a sample melody made with the C major scale, so take a listen.

To find the "basic four-note chords" that can accompany this melody, let's learn how the four-note major diatonic chords are formed.

How Diatonic Chords (Four-Note Chords) Are Formed

This time too, we'll build them in the key of C, so prepare the familiar C major scale.

For four-note chords, on the first note, "C," stack three notes to the right, skipping one note each time.

After "C," stack "E," then "G," and then "B."
In a DAW, copying is a good idea.
This gives you a C major seventh chord.

Repeat the same procedure, but at "E" you run out of notes to stack.
As with triads, it's easier if you also program the second octave of the C major scale.

Once you've done this up to B, you have a group of four-note chords starting on each note.

These are the diatonic chords (four-note chords) of C major.

If you can't tell what the chords are, try making C the root of all the chords.
Shift each chord so that its lowest note is C.

The top note is what differs from triads, so pay attention to it.
You can clearly see the characteristics of the four types of seventh chords we've covered so far.

Put them back and look at the structure of the four-note diatonic chords.

From left to right, they follow the order

major seventh, minor seventh, minor seventh, major seventh,
dominant seventh, minor seventh, minor seventh flat five

.
As with triads, this structure doesn't change in other major keys.

Example: D major diatonic chords (four-note chords)

Adding Diatonic Chords (Four-Note Chords) That Fit the Key

Now let's add C major diatonic chords (four-note chords) to the key-of-C melody shown above.

As you can see, it's built entirely from C major diatonic chords (four-note chords), and it doesn't sound out of key; it fits naturally.
Also, unlike triads, it feels like it carries bittersweetness and complex emotions.

Next time, we'll step away from diatonic chords for a moment and learn ways of applying chords that can also be used in actual arrangements.
First, we'll focus on writing songs in major keys.
Doing so will make minor diatonic chords easier to understand.

Frequently Asked Questions

Q1. How do triad diatonic chords differ from four-note chords?

Four-note chords add a seventh (the 7th degree) to triads, giving the chords richer color. They can be mixed with triads, and four-note chords are especially suited to expressing poignancy and complex emotions.

Q2. Can the same diatonic chord structure be used in every major key?

Yes. The order of major seventh, minor seventh and so on doesn't change whether the key is C or D, so you can apply it by matching it to the scale.

Q3. Please tell me the order of the four-note diatonic chords in C major.

The order is C-M7, D-m7, E-m7, F-M7, G-7, A-m7, B-m7♭5. Making the lowest note the root for all of them makes each chord's quality easier to understand.

Q4. Are there tips for efficiently creating these chords in a DAW?

Preparing two octaves of the scale and copying and pasting is efficient. The process of stacking notes while skipping one each time becomes easier to see, reducing mistakes.