Jazz Guitar Chords w Extensions
Extensions add color and interest to a guitar chord. Extensions are those note of the scale that are not chord tones, so the notes in between 1, 3, 5 and 7. For more information visit guitar music theory page 3.
Let's start with the extensions of major guitar chords:
The Extensions of Major Guitar Chords
Our starting point will be Cmaj7 on the 3rd position:
The first extension we want to add is the 9. If you followed the guitar music tutorial you know that the 9 is in fact the second note of the scale, but an octave higher (2 + 7=9). When we add the 2 to a chord we don't call it for example the guitar chord D2, but D9.
The 9 of C is a D. On the B string we could change the E to a D, but that would leave us a chord without the 3, which is an important note. So we have to change the voicing to be able to add the 2 and still have the 3 and it goes like this:
To this chord we can add another extension: the 6. Most of the time when a 6 is added to a chord the 7 is omitted because they get in each other's way. So we change the 7 of the above guitar chord to a 6 and that gives us a C6,9:
That's it for the major chords, because the 11 is an avoid note (a note that doesn't sound good) for major chords.
The Extensions of Minor Guitar Chords
Our starting point is this Cm7 chord:
We want to make it a Cm9, so we change the Eb for a D:
To this chord we can add a 6:
or an 11:
The Extensions of Dominant Guitar Chords
The starting point is this C7 voicing:
We can add a 9:
and a 13:
We can also add altered extensions (tensions from the altered scale):
Adding the #9 gives us the famous Jimi Hendrix chord:
We can also add a b9:
The 4 is not really an extension for dominant chords. Adding the 4 makes the chord a sus chord. The sus chord functions as a delay to dominant chords and I'm sure you know the sound of it from disco music.
Here's a typical C9sus4 chord: