Major Seventh Chords and Inversions

Now it’s time to go beyond triads, into the world of four-part chords called seventh chords. When we add a fourth note to a triad, it is often the 7th of the chord, as the triad already contains the root, 3rd, and 5th. That is why four-part chords are sometimes referred to as “seventh” chords. The first four-part chord we will look at is the major seventh chord:

As with the triads in Chapter 10, the intervals from the root have been indicated (major 3rd, perfect 5th, and major 7th). These major and perfect intervals are found within the major scale, so you may think of this chord as the first, third, fifth, and seventh degrees of a C major scale.

The chord symbol above the staff is now Cmaj7. There are two components to this chord symbol: the root (C) and the suffix or description (maj7).

Like the triads, these four-part chords can also be inverted. Here are the inversions of a C major 7th chord:

We’ll define these different inversions of the C major seventh chord as follows:

• the first chord is in root position (with the root on the bottom)
• the second chord is in first inversion (with the third on the bottom)
• the third chord is in second inversion (with the fifth on the bottom)
• the fourth chord is in third inversion (with the seventh on the bottom)
• the last chord is in root position, an octave higher than the first.