I've been playing a bunch of crazy tunes in my jazz combo at SDSU this semester. Old familiar chord sequences like ii-Vs or dominant to tonic cadences are starting to seem foreign; we never see each other lately. Much of this new material is in the "chromatic modal" idiom, in which chords progress by non-tonal means. Each chord, considered in isolation, presents no improvisational difficulties. Most are actually basic 7th chords with familiar extensions: m9, maj7#11, 13sus4, maj7#5, m/maj9. I know what to do with all of those. The issue is the speed at which they go by. Since they're not connected by any key center, even at low tempos the improviser must navigate through a new harmonic setting every couple seconds. Weaving melodic lines through this rapidly changing landscape presents a challenge rarely found in the jazz standards I've been working on for the last two years.

In addition to performing in this style, I'm also required to compose a few tunes of my own. I enjoy the creative freedom when any chord can follow any other chord, but it's tough work getting my ears and mind into the relationships between adjacent chords. I know what to do about my ears: listen. I listen to as much of the music as I can, and I zoom in on these harmonic moments with my guitar or a keyboard to hear the voice movements and the strange new ways to effect tension and release. That just takes time.

Wrapping my head around this stuff has been more painstaking. As a guitarist, I rarely play a complete chord voicing in real playing situations, due to the physical limitations of the instrument. Pianists, with ten fingers capable of hitting close-voiced clusters of notes, have no problem filling out all the indicated extensions of any given chord. So, in order to visualize the movement of all these notes from chord to chord, one must either see it all happening on a staff (hard) or play through the chords on a piano (hard for non-pianists). It's helpful for any musician to have some basic piano skills, so I've been plunking through the latter approach, but every chord is a mental workout. It's strange territory.

Here's where my new concept comes in. I found a third method of visualizing these harmonic movements, via the cycle of fourths. I apply the complete 7-note scale to each chord and visualize its layout on the cycle. Here's the C Major scale, which is equivalent in this visualization to F Lydian, G Mixolydian, D Dorian, A Aeolian, E Phrygian, and B Locrian:

This pitch class set would apply to a variety of chord symbols: Fmaj7#11, G7sus4, Dm13, Am9#5, Dm11/E, anything that implies the above scales.

I can use a similar diagram for Melodic Minor-based harmony. The following set is C Melodic Minor, equivalent to Eb Lydian Augmented, F Lydian Dominant, G Mixolydian b6, D Phrygian Natural 6, A Locrian Natural 2, and B Altered Dominant:

And this can be used with all the chord symbols which imply the above scales: Ebmaj7#5, F7#11, Cm/maj7, Dm9b5, B7#5#9, etc.

So what's the point? Now I can see how these extended harmonies relate to each other in a progression. Take the first few chords of Wayne Shorter's "Nefertiti": Abmaj7b5, Db7sus4, Gm7b5, C13b9. The applied chord-scales here are Ab Lydian, Db Mixolydian, G Locrian Natural 2, and C Symmetrical Dominant. Now I just move the above visualizations around the cycle of fourths to the appropriate parent Major or Melodic Minor scales, and I get the following pitch class sets:

Ab Lydian (Eb Major)

Db Mixolydian (Gb Major)

G Locrian Natural 2 (Bb Melodic Minor)

C Symmetrical Dominant

(Note that we haven't seen the C Symmetrical Dominant shape yet. It's an 8-note scale, not a mode of Major or Melodic Minor, and is equivalent to Eb, Gb, A Symmetrical Dominant and G, Bb, Db, E Symmetrical Diminished.)

Visualizing the chord symbols in this manner helps me see the following:

• Db, Gb, and B are new notes in the Db7sus4 harmony not in the previous chord.
• A, G, and C are new notes in the Gm7b5 harmony not in the previous chord. (Or only G and C if G Locrian is used instead of G Locrian Natural 2.)
• Gb and E are new notes in the C13b9 harmony not in the previous chord.

Seeing the diagrams separately as above is a little hard on the eyes when trying to see which notes are new. It's easier to see them in my head after I've gotten used to this way of thinking. Even better when I can watch them go by on my screen. Here are all the chords to "Nefertiti" in a little slideshow. Click the image to manually advance, or use the controls underneath.