"Good improvisation communicates harmonic progression melodically. Effective melodies manipulate harmonic content through the use of guide tones and preparatory gravity notes, masterfully woven in systematic tension, release, and transparent harmonic definition."
This week's Tips and Tricks entry is our first from newly hired JazzMando staff writer and Traverse City, Michigan mandolin master, Don Julin.
A lot has been written about the ii-V7-I chord progression and how it is in many ways the foundation of jazz harmony. Let's take a closer look at this vehicle in hopes of simplifying it. Let's first look at any western music and the V7-I cadence. Imagine we are playing a tune in the key of G. The chord with the most tension or unresolved would be the D7. Try it for yourself. Make up a chord progression using diatonic chords in the key of G. (G, C, D7, Am, Bm, Em,) Try stopping the progression on the D7 chord. It sounds like a question doesn't it? Now play the same progression and continue from the D7 to the G chord. Ah.... resolve or answer. Now try G, D7, G. Hear how the sound goes from resolve to tension and back to resolve.
One of the compositional elements of jazz music is the fact that keys change quite often. For this experiment we will pick 3 keys that seem to be unrelated. G major, B major, and Eb Major. Just for fun let's make up an eight bar chord progression by playing 2 bars of each key using only the I chord of each key. G/G/B/B/Eb/Eb/G/G/. Sounds a bit strange and does not have much direction. Now substitute the V7 chord for bar one of each key. D7/G/F#7/B/Bb7/Eb/D7/G/. This sounds better but more like Bach than Coltrane. The dominant (V7) chord supplies some tension and pull to the next key. Now try splitting the first measure of each new key with a iim7 chord. Am7 D7/G/C#m7 F#7/B/Fm7 Bb7/Eb/. Now we are getting closer to a jazz sound. Next we will make the I chord into Major 7th chords. Am7 D7/Gmaj7/C#m7 F#7/Bmaj7/Fm7 Bb7/Ebmaj7/Am7 D7/Gmaj7/. This is only the tip of the iceberg but you can see one common way that jazz composers modulate from one key to another by using the ii-V-I chord progression.