Jazz Improvisation Modal Substitutions

To continue with the ideas as set-out in one of my previous blogs regarding John Coltrane's 'Giant Steps' involving what I call 'transfiguration' (a process of substituting sequences of V-I or ii-V-I tonal areas with relative linear tonal areas) I am here turning my attention to a 'fluid' linear modal system. Linear harmonic chord voicing is a major part of classical composition (e.g. writing in the style of a four-part J.S. Bach Choral is standard practice) where leaps in each voice (bass, tenor, alto, soprano) are kept to a minimum and cadences observe particular rules (e.g. in a V7 chord, the 7th resolves downwards by one semi-tone step to the major 3rd of chord I). My 'fluid' linear modal system allows the soloist to almost instantly analyse a chord progression, understand the 'tonal' area and apply a scale-mode that corresponds with adjacent tonal areas and apply a suitable mode in a key according to linear principles.

An understanding of diatonic and modal scales, linear voice-leading melodic compositional techniques, jazz chords and harmony, and improvisation is required for full comprehension of this blog-post.

The music example I will use here is the jazz-standard 'Just Friends' in the key of C major. It is necessary to understand the tonal areas before applying any further analysis:

4/4 G7 || C maj7 | C6 | Cm7 | F7 | Gmaj7 | G6 | Bbm7 | Eb7 | Am7 |

(first time) D7 | Bm7 | Em7 | A7 | A7 | Am7 D7 | Dm7 G7 :|

(second time) D7 | F#m7 | B7 | Em7 | A7 | Am7 D7 | Gmaj7 ||

Select a tonal centre to 'think in'. That will probably be C major to start with. The piece opens with (G7 - C maj7 - C6) or V - I in C major. Improvise C Ionian major scale here. Then Cm7- F7 follows or ii7-V7 of Bb major. Here you have a linear choice, either improvise in Bb major Ionian or, preferably, you can play the second mode of Bb major, which is C Dorian. In other words, you can improvise a phrase in the previous tonal area, and simply transfigure the notes of the motive to fit the new 'minor' sounding Dorian mode.

E.g. C,D,E,F,G,A,B,C (C major) becomes transfigured: C, D,Eb, F,G,A,Bb,C (C Dorian)

The sequence Gmaj7 -G6 is a case in point for unnecessary switching of thinking. Even though you can use the G major Ionian scale over G maj7, think linear and use the 4th Lydian mode of G major which is C Lydian. Again, the previous tonal-area was C Dorian and your phrase/s may be transfigured to C Lydian. Thus, you may continue easily reworking your phrases without jumping from key to key.

E.g. C, D,Eb, F,G,A,Bb,C (C Dorian) becomes transfigured: C, D,E, F#,G,A,B,C (C Lydian)


With the above you can of course apply this theory to commence your tonal centre in a completely different place. I'll show the transfiguration to a tonal centre to G. You simply count through the mode order

1. Ionian, 2. Dorian, 3. Phrygian, 4. Lydian, 5. Mixolydian, 6. Aeolian, 7. Locrian:

E.g.
C,D,E,F,G,A,B,C (C major) / C, D,Eb, F,G,A,Bb,C (C Dorian) / C, D,E, F#,G,A,B,C (C Lydian)

can be transfigured to:

G Mixolydian (C major but G-G) / G Aeolian (Bb major but G-G) / G Ionian (G major). This system is completely fluid but as long as you understand your modes! If you analyse and discover a Eb major tonal area for instance, then Chord ii of Eb is always F minor and the corresponding second degree mode is Dorian giving you F Dorian. Subsequent keys can be transfigured on the spot to find a suitable mode in the key of F or its adjacent tonal-area neighbour E or F#.

I believe that this system, whilst perhaps might be too much of an undertaking for an amateur, it is during medium-fast and faster jazz music where thinking and jumping becomes hard, and at times impossible to implement standard scale-key thing instantly. Try testing your knowledge here by trying the other way that amateurs often prefer to use.

Take the first four notes of B major and write them out. Now imagine you are about to play a phrase in imitation and you want to make the first note of each canon (imitation) climb upwards one step at a time. When you stay in the one key this is easy:

E.g.
phrase 1 B, C#, D#, E
phrase 2 C#, D#, E, F#
phrase 3 D#, E, F#, G#
phrase 4 E, F#, G#, A#

Now (and this is what I think is too complicated to implement at speed), imagine that the tonal centres are changing at around 260pm or higher in 4/4 time. Compose a imitative upwards moving phrase sequence in the following keys:

phrase 1 [B Major] B, C#, D#, E
phrase 2 [Ab Major] , , ,
phrase 3 [D Major] , , ,
phrase 4 [F Major] , , ,

How did you do? Now try to compose and transfigure your own motives using this fluid linear modal system and see how you get on. Message me with your results perhaps?

Dale Harris copyright c.2009 All rights reserved