CHAPTER 1

Seventh Chords

Every musician loves a new trick that can quickly expand their repertoire. In this chapter you’ll learn about an easy way to raise the level of sophistication of your music through a new type of chord called the “seventh” chord. Seventh chords are just extended versions of the chords you already know; they contain an extra note that adds complexity and lets you do some really neat things. For example, the “seventh” version of V can be used to enhance its qualities as a progression-ending “cadence” chord; the “seventh” versions of ii, iii, and vi can be used to make a progression sound more smooth and mellow; and inversions of seventh chords can be used to connect baselines in new and beautiful ways.

1.1 Extending The Basic Chords

In the first chapter of Hooktheory I you learned that the basic chords each contain three scale degrees as shown below:

Scale degrees of basic chords

Each basic chord is formed by starting with a root note and then stacking two more notes on top of it, omitting every other scale degree. So-called seventh chords simply add one more note to each chord following the same pattern. In this way you get chords consisting of four scale degrees, as shown below:

Scale degrees of seventh chords

To distinguish seventh chords from their basic counterparts, a superscript “7” is placed next to the Roman numeral. For example, to make a normal I chord into a seventh chord, you add scale degree 7 and call it I⁷ (read “one seven” ). To make a ii chord into a ii⁷ (read “two seven”) you add scale degree 1 to it. The reason these chords are called seventh chords is that the highest note is seven scale degrees away from the root.

The sound of seventh chords

Seventh chords are very similar to their basic counterparts, and yet their presence can still alter the sound of a song quite a bit. To hear how the feel of a song can be affected, let’s listen to a familiar progression without seventh chords and then swap in “seventh” versions and listen for differences.

Basic I → IV → ii → V

Here is the same progression but now all the chords have been changed to seventh chords:

I⁷ → IV⁷ → ii⁷ → V⁷

The “seventh chord” version of the progression has a mellow, more complex sound than the original; it’s amazing how one extra note can change the feel so substantially. At the same time, the overall sound of the second progression does have a lot of similarities with the first. These are clearly “the same” chords; they’ve just been adapted from the originals.

This progression is used in Robin Thicke’s R&B hit “Lost Without U.” Below you can hear how it works alongside a melody to create a smooth, soulful sound.

“Lost Without U” by Robin Thicke

“September” by Earth, Wind & Fire is another example of a song that makes heavy use of seventh chords and syncopation to give it its funky groove.

“September” by Earth, Wind & Fire

Now that you have a sense of what seventh chords can do for your music, we’ll learn more about how they relate to their basic counterparts. Then we’ll learn about the function of seventh chords and see how songwriters use them in their songs.