Question by Fred
In going through your series on the page “Jazz Improvisation #1” I noticed that the first PDF notes a D7 chord in the 8th bar, but the notes don’t seem to match the chord outline (C-Bb-A-G-F# over D7).
See the PDF in question here…
Am I missing something here?
This is a nice question.
Well, sadly, yes: you are missing a little something. In a classical harmony sense, dominant chords that are a minor third appart (F7, D7, B7, Ab7) share a common diminished scale … I don’t want to get too involved into the theoretical reasons why it works, but let’s simply do an analysis of each note.
We are playing the F Mixolydian scale ascending to fit the F7 chord in bar 7 (F G A Bb C D Eb). So far, so good. the analysis of the notes are 1 2 3 4 5 6 b7, which is exactly the mixolydian mode. Right?
Now about that D7 … instead of playing the mixolydian mode for D7 (D E F# G A B C), we instead stick to the F mixo mode BUT we modify one note. The F natural becomes an F sharp.
So the scale used for D7 (starting from F#, not as written on the PDF) is simply F# G A Bb C D Eb. Let’s analyze each note from a D root note standpoint:
F# — 3
G — 11
A — 5
Bb — b13
C — b7
D — 1
Eb — b9
Wow, okay! So nothing is fishy here, right? We have a basic D7 arpeggios (1 3 5 b7) and then extensions (b9 11 b13).
In summary: in bar 8, we are simply playing on a D7(b13 b9) scale, some sort of very common altered chord / sound.
In fact, this scale is simply G harmonic minor. Look at it closely! So, by simply changing that F to an F# when descending the F mixolydian scale, we are preparing our ears to have some sort of a G minor sound next …
… and guess what is happening in bar 9. Yes, Gm7! 🙂
So, no need to play a completely different scale (D mixo for instance) in order for us to hear that a G minor chord is up next. Changing to that F# suffices. Least effort for maximized results.
I hope this clear things up for you.
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