Compositional Elements - Harmonizing Scales...The Simple Origin of Chords

Hi guys,

In the previous posts of this Compositional Elements series we looked at the major scale and it's relative natural minor scale. In this post we will look at how we can derive chords from scales. This is called "harmonizing a scale" or "scale harmonization".

Where do chords come from?

Chords are the result of a process called "stacking thirds". We are basically taking 3rd intervals and stacking them one on another. Let's look at the C major scale to see how this is done.

C D E F G A B C
Now, let's take every 3rd interval starting from our tonic note C.

C E G B
These are the notes of the first chord we can derive from our C major scale. It happens to be a C major 7 chord.

We can continue this way to derive chords from each note of the scale. Let's now start from the note D.

D F A C
These are the notes of the second chord we can derive from our C major scale. It happens to be a D minor 7 chord.

And so on...

This is the result of our harmonized C major scale:

I = C E G B = C major 7
ii = D F A C = D minor 7
iii = E G B D = E minor 7
IV = F A C E = F major 7
V = G B D F = G dominant 7
vi = A C E G = A minor 7
vii = B D F A = B minor 7 flat 5

Notice how the chord qualities vary. No matter the key, you will always end up with this fundamental structure.

I = I major 7
ii = ii minor 7
iii = iii minor 7
IV = IV major 7
V = V dominant 7
vi = vi minor 7
vii = vii minor 7 flat 5

These chord qualities can be understood better by knowing the formulas. Don't worry too much about that now, but this attachment will give you a look ahead.

Exercise

What is the iii chord in the key of A major?

What is the IV chord in the key of D major?

What is the V chord in the key of F major?

If you found this useful please upvote and follow. Thank you!