Extensions – 9, 11, 13

“Extensions” is the name given to the other notes – the non-chord-tones – in any scale. Here are the chord-tones and non-chord-tones in a C major 7 chord. Notice that you wind up with a C major scale.

C          D          E          F          G         A          B

They’re called extensions because, as you build the chord up in thirds from the root, they extend into the next octave. In that octave, they’re called the 9, 11, and 13. Within the octave, they’re called the 2, the 4, and 6.

C(1)   D   E(3)   F   G(5)  A    B(7)  C   D(9)  E    F(11)   G    A(13)     

In order to get a feel for how these notes sound, do the same thing that you did for the chord tones a few posts ago:

1. Loop a single chord. Use a Cmaj7 chord for simplicity.
2. Play the 9th and nothing but the 9th while the chord plays. Really figure out how that note makes you feel. Play it with the same articulation for a while (soft, hard, staccato, etc.). Then vary the articulation. Don’t vary the rhythm. Keep asking how it makes you feel. Don’t worry about coming up with an answer. The point is to feel, not explain.
3. Do the same thing with the other extensions – the 11 and 13.
4. Improvise using only two extensions. Your choices are 9 and 11; 9 and 13; 11 and 13. Play around with each pair.
5. Use all three extensions in the same manner.
6. Use every note in the scale.

If this feels tedious, remember you’re laying the groundwork, really getting to know how every note makes you feel. You can ignore all this, but you won’t feel what you’re doing as deeply.