Song 11

  1. Semitone Symmetry
  2. The Jam Factory
  3. Phrasing - using non scale-tones
  4. Practice - Symmetric scales
  5. Session Materials

    Chromatic fingerings


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S 11.1 - Semitone Symmetry

jf003.gif In the Session 10 I introduced the concept of Whole-tone symmetry which produces musical elements using intervals consisting of an even number of semitones (whole tones, and multiples of whole tones).

Semitone symmetry is a second form of simple symmetry, where the symmetrical interval consists of an odd number of semitones.

There is a distinct difference in sound between these two groups.
Whole-tone symmetry produces aggressive, angular sounds invariably used over dominant, augmented and altered major chords.

Semitone symmetry, on the other hand, produces much smoother sounds, from which all aggressiveness and angularity have disappeared.

Semitone symmetry can be applied over any chord in any situation, providing a lubricant between one chord (or tone) and the next, and at the same time contributing an additional colour to the music.
There are only two elements with simple semitone symmetry in music. They are the Chromatic scale and the diminished 7th chord.

In the Chromatic scale all notes are spaced at intervals of one semitone. It contains all notes used in our present system of traditional Western music.
Initially notes of the chromatic scale were simply used to add colour ("chroma" means "colour") to other (major and minor scale) tonalities.

From the early 1900s the scale started to become used in its own right (e.g. in the atonal music pioneered by Arnold Schönberg). To mark this upgraded use the name Dodecaphonic scale (meaning "twelve-tonal") was introduced, however this name never really took hold.

Audio 11.1

The Chromatic scale is, like all other symmetrical elements, ambiguous in its tonality. Any note of the scale can function as the tonic note, but the feeling of a tonal centre is absent. The sound of chromatic scale segments and simple semitone movements can be as smooth as butter (as in Scott Joplin's 'The Entertainer'), but it can also produce a "spooky" mysterious sound (like in the film "Jaws"), especially when going upwards in pitch.

Audio 11.2

The four notes of the diminished 7th chord divide the octave into four symmetrical intervals of three semitones (a 'minor 3rd' interval) each.

Audio 11.3

The diminished 7th chord is the ideal and commonly used tool to harmonise non-chord or non-scale tones in a melody. It is also used (especially in the older Trad Jazz standards) as a passing chord between two chords to smooth out a chord progression.
For example :

Audio 11.4

The diminished triad (such as Co = C Eb Gb), although strictly speaking not a symmetrical chord, is used in the same way as its bigger brother (Co7 = C Eb Gb A). It can be interpreted (by the ear) as a diminished 7th chord with one note missing in the voicing.

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S 11.2 - The Jam Factory

The Jam Factory is a 32 bar song in AABA format. It has the same chord progression as one of the most famous Standards of the Jazz repertoire : I Got Rhythm by George Gershwin.

The chord progression of this song is used in numerous other Jazz standards. Famous examples include Oleo by Sonny Rollins and Anthropology by Charlie Parker.
Jamey Aebersold lists 61 titles in his Vol.47 - I Got Rhythm Changes in all Keys Play-a-Long CD set.
I have used simplified versions of it for my songs 'Hey There', 'Where's Woody?', 'At the Hannans Ball' and 'Swing Time'.

Note the long phrase of quavers (4 bars plus 1 beat) over the first half of the A section of The Jam Factory.


The A section of The Jam Factory consists entirely of the popular chord segment

I - VIm7 - IIm7 - V7
in C = C - Am7 - Dm7 - G7

All chords are scale-tone chords of the same scale (C major in the case of 'The Jam Factory'). This makes improvisation over the A sections very easy, as you only need to use the one C major scale to cover all chords.

Audio 11.5

The Bridge of The Jam Factory consists of two 4 bar phrases with identical rhythm patterns.
The melody in the second phrase "echoes" the first phrase, shifted one tone down with appropriate alterations to fit the chords. (This can also be a very effective ploy in improvisation.)

Audio 11.6

The chords in the Jam Factory Bridge (or 'B section') represent the so-called Rhythm Bridge used in numerous Jazz standards.
In this section the song modulates to a new key with every new dominant chord.

III7 - VI7 - II7 - V7
in C = E7 - A7 - D7 - G7

Audio 11.7

You therefore need to use four different scales for improvisation over the Bridge.
Here is a good Practice routine to use.

Audio 11.8

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S 11.3 - Phrasing : Using non scale-tones

In the selection of which notes to use for improvisation you have two choices.

  1. Playing inside the tonality that fits the chord.
    This consists of scale segments, arpeggios and large intervals within the scale.

  2. Playing outside the tonality that fits the chord.
    This can be done in two ways.
    • deliberate selection of a scale that partly or entirely does not fit the chord, like we did for example in Y2K Blues.
    • or by occasionally adding a non scale-tone to the improvised melody.
      In this case you do not really play outside the tonality, but merely add colour to it.

jf001.gif Work in this session on adding a non scale-tones to your improvisation. This can be especially effective over large areas which are covered by one scale only, such as the A sections of Jam Factory. Be careful not to overdo it, otherwise the tonality gets to vague to be meaningful.

By using non scale-tones you are in effect using the tonality of the chromatic scale. As this scale contains all the notes of the musical system it "fits" over any chord imaginable.
You can therefore include a chromatic run at any point in any of your improvisations. This can be very useful when you run out of ideas or wish to shift to a higher or lower pitch level in your improvisation.

Swapping twos
Again included in this session some tracks swapping twos.

  • On Jam Factory 1 I play every first two bars of each 4 bar phrase, you play the last two bars.

  • On Jam Factory 2 I play every last two bars of each 4 bar phrase, you play the first two bars.

  • On Jam Factory 3 you can listen to the combined result.

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S 11.4 - Practice : Chromatic and Whole-tone scales

Practice the chromatic scale and the whole-tone scale over a 2 octave range on your instrument. Learn to start and turn these scales on any note.

Chromatic scale fingerings for Keyboard - Saxophone - Clarinet - Flute are included in a separate article.

I have no expertise in fingering technique on other instruments (brass, strings, etc.), and recommend you check these out in a good tutor book for your instrument.

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S 11.5 - Session Materials

ItemMidi fileSheet music
Jam FactoryDemo P-a-L C instr.Bb instr.Eb instr.
Easy Key for Bb instr. (C)E-PalC instr.
Easy Key for Eb instr. (C)E-PalC instr.
Symmetric scalesp.1
Chromatic fingeringskeyboardsaxophoneclarinet
Swapping Twos Jam Factory 1 Jam Factory 2
Swapping Twos (Demo) Jam Factory 3

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© 2003 Michael Furstner (Jazclass)