There’s a certain snobbery around extended chords. After all, anyone can write a song that uses chords like C, Am, G and Em. It’s so much more impressive when yours goes C9, Am9, Gadd9 and Em9, even if it’s basically the same chords with some added notes!
A major triad consists of the root, the 3rd and the 5th notes of a major scale. A dominant seventh chord places a minor seventh on top of that. But we can keep on going.
Go two notes further up the scale and we get a 9th, two more again an 11th and another two more gives us a 13th. And that’s where it stops because we’ve now got seven different notes in the chord and a 15th would just take us round again to the root of the chord (not to mention we’re going to run out of fingers or, in the case of a guitar, strings to play these notes on!).
We can do the same with a minor chord:
So, why do we need all these additions to what are perfectly usable chords? The answer is that they change the mood. Here’s a simple chord sequence without any extended chords. The progression goes Am D7 G E7 Am D7 G.
Now here’s the same chord sequence with a variety of embellishments:. It goes Am9 D13 Gmaj7 Eaug Am7 D13 Gmaj7. The 9th adds a B to the Am7 chord. The 13th adds a G and a B to the D7 chord. As you can hear, these additional notes ring through and imply a wholly different melody. The overall feel is more jazzy, which may or may not be what you want:
If you’re a guitar player, you might be interested in how I played the chords in the embellished version. You can add the E9 to the end of the sequence as a way of linking back to the start.
Here’s a piece for solo guitar, called Princelet Street. The main recurring theme is based on a Cm13 chord, and it is this chord that inspired the whole composition. Adding 9ths, 11ths and 13ths to chords can provide all sorts of unexpected ideas for melodies and, for me, that’s a good enough reason to give them a go.
Guitarists who want to take a closer look at Princelet Street can download the notation and tablature below:
I had a look for examples of 9ths, 11ths and 13ths in music other than jazz. Now you will find all sorts of rich chords, especially major and minor sevenths, in more sophisticated soul music (Stevie Wonder’s a great example), but extensions into 9ths and above are still a rarity. I don’t know about you, but I reckon we have an opportunity here. It’s time to raise the odds.