In the chapter on seventh chords, you were introduced to one way that the basic chords could be extended to give your musical ideas more complexity. In this chapter, we will learn about several other ways to alter and extend chords that can create some surprisingly beautiful sounds.
As a rule, the more scale degrees a chord has, the more complex it sounds. Seventh chords have more dissonance than the basic chords, for example, because they have four notes in them instead of the usual three; seventh chords are formed by stacking an additional scale degree on top of the three that make up a basic chord. We can extend this same stacking pattern, adding even more scale degrees to form more complex chords.
Ninth chords, for example are created by taking a seventh chord and adding the ninth scale degree relative to the bass. Eleventh chords are created by taking a ninth chord and adding the eleventh scale degree relative to the bass, and so on. Because these chords are formed by extending the seventh chord pattern of stacking every other scale degree, they are known as extended chords.
As this example demonstrates, the more unique scale degrees a chord has, the more complex and dissonant it sounds, because there are more notes interacting with one another. As a result, extended chords (ninth, eleventh, and thirteenth) are not nearly as common in popular music as seventh chords. Because of this, we won’t we discussing them in detail in this book. That said, many of the concepts we’ve learned about seventh chords (inversions to connect bass lines, usage in secondary chords, etc.) apply to extended chords.
The extra complexity and dissonance of extended chords have made them common in jazz and other genres of music that adhere less to (or that go beyond) the traditional rules of music that we have been studying thus far. Below is an example of a song that uses extended chords so you can get a feel for how they sound in context:
While extended chords are rare in popular music, variations of them with some notes omitted to reduce their dissonance show up often. In the next section, we will discuss a chord that is very similar to a ninth chord but much more useful in practice.
Check for Understanding
A seventh chord has four total inversions (root position, first inversion, second inversion, and third inversion). How many total inversions would a ninth chord have?