Advanced Chords tutorials
3. The I-IV-V-I progression and chord substitutions
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So do chords like...get substituted like in football or basketball now?

  1. Topics of discussion
  2. The I-IV-V-I progression
  3. Diatonic chord substitutions

1. Topics of discussion

In this tutorial, we are going to take a look at another chord progression which serves as a basic one for composing your own music, while also learning how we can substitute chords in a progression. So, let's have some fun.

2. The I-IV-V-I progression

The I-IV-V-I progression, while not as common as the I-V-vi-IV one, is actually easier to use when writing songs. The reason behind this is the fact that it contains only the primary chords of a scale:

  • the tonic chord (I)
  • the subdominant chord (IV)
  • the dominant chord (V)

As you recall, when creating a harmony (which is a synonym for chord progression) using these chords, you can play any melody on top of them with the notes from the scale which they are part of and it will sound good.

If one were to write songs using only the primary chords, then one's music would quickly become boring. So, how do we add color to our chord progressions? By using chord substitutions.

3. Diatonic chord substitutions

A chord substitution occurs when we replace a primary chord
with a secondary chord that can play the role of the primary chord which it is replacing.

So, how does one figure out which secondary chord replaces which primary chord? It's something like this:

  • the chord located a third above a primary chord can be used to substitute it
  • the chord located a third below a primary chord can be used to substitute it

What this translates to is the following:

  • the I, iii and vi chords can be used as tonic chords
  • the IV, vi and ii chords can be used as subdominant chords
  • the V, vii and iii chords can be used as dominant chords

"Wait, what? But there are some chords which can play both roles...what gives?"

So...how does this work? How do we know what type of chord we are substituting? And how does this help our progressions?

Obviously, whenever we are substituting chords, we are of course adding our own twist to the song. As you can see, the ii and vii chords have an obvious role, in that they are a subdominant chord substitute and a dominant chord substitute respectively.

As for the others, they serve the purpose of allowing you to extend your chord progression. And the role thay they play in your progression is determined by the chord played before them.

For example, if we were to play a chord progression like I-iii-IV-V, then the iii chord is used as a tonic substitute because it is played after the I chord. However, if we are to play a I-IV-V-iii progression, then the iii chord would be acting as a dominant chord substitute, because it is played after the V chord.

Aside from the obvious ones, let's take a look at the progression from the previous tutorial: I-V-vi-IV. What kind of a role does the vi chord play here? The answer is a tonic substitute, because it fith the description, with the vi degree of a scale being located a third below the tonic note, if you look at it as subtracting a third from the root note.

The same can be said for this progression: I-IV-iii-V. The iii chord acts as a tonic substitute, because it fits the bill, what with the iii degree being located a third above the tonic note and such.

That about covers it for this tutorial. Next time around, we are going to learn to look at chords from a different perspective. See you then.

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