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The ‘Tetrachord’ – Part 2

Jazzed Magazine • August/September 2019Focus Session • August 28, 2019

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The following is an excerpt from Chris McNulty’s Vocalist As Complete Musician – VCM

Previously, in the April/May 2019 issue of JAZZed: The Melodic Minor scale introduces us to the Diminished Tetrachord along with the four tetrachords already identified from the Major scale above. In this exercise we’ll discover the source of some of the more colorful and interesting chords and scales used in jazz harmony. Take your time to familiarize yourself with the information I’ve included above and below the staves. The first thing you’ll notice is the delineation of “Parallel” and “Derivative” use. Parallel defines the scale from the root of the chord. Derivative defines the scale from its “Parent scale” – the parent scale referenced in this exercise is the Melodic Minor scale. This may not make sense immediately. However, as you move through this work the difference will become clearer. Learning how it can assist you as an improvisor in analysis and choosing/hearing scale choices over chords is integral.

The first degree of a scale is the only instance where Parallel and Derivative are one and the same. In each system event (above the stave) both Parallel and Derivative uses are suggested, as well as the chord quality and its name. On each track you’ll first hear the chord, the root or starting note, followed by tetrachords. We always start at the first degree of the scale then move to the second degree, playing/singing the accompanying chord and tetrachord and so on and so forth. Go through this exercise either with the track or at the piano a few times a day for a week or more or until each scale degree and its accompanying chord are identified and heard (using the tetrachords I’ve given you) before moving on to the Harmonic Minor scale.

The Harmonic Minor Scale — (H3, H13, Maj 7)

The Harmonic Minor scale introduces us to the Harmonic tetrachord which has the following intervalic structure: 1/2 step, minor 3rd followed by 1/2 step. It occurs at the 5th degree of the Harmonic Minor Scale and is also called the Arabic scale. Starting on “C” it includes these four notes: C, Db, E, F (a Harmonic tetrachord) followed by G, AH, BH, C (a Minor II (phrygian) tetrachord. The Harmonic Minor scale is also where we first see the appearance of a “non-tetra chord” event. I’ve delineated with *** where they occur. Don’t overly concern yourself with these “non-tetrachords” events. Our main interest is with three particular chord types that source from the 1st, 3rd and 5th degrees of the Harmonic Minor scale. The bookend tetrachords from each of these three scales include either Minor I, Harmonic, Major, Diminished, or Minor II.

Exercise 5a: The Altered Scale (7th Mode of Melodic Minor)
Extra Drilling in All 12 Keys

Practice learning and hearing the Altered Scale over its accompanying Dom 7th chord quality Augmented 7 (H9, #9, H13). This exercise will also reinforce the method behind learning how to identify, hear and utilize the difference between Parallel and Derivative use. I’ve included the exercises in all 12 keys to give you more time to integrate. By identifying the chord type and reading the notes, it not only becomes an extra theory drill but will improve your reading skills across all 12 keys. Learn to read in both treble and bass clef. We’ve sung/played the first six chords and left the remaining six for you to play/sing.

Exercise 5c: The Arabic Scale (5th Mode of Harmonic Minor)
Extra Drilling Over All 12 Keys

Practice learning/hearing the Arabic Scale over its accompanying Dom 7th chord quality (H9, H13). These tools are provided to assist in identifying, hearing and utilizing the difference between Parallel and Derivative use.

Chapter 4 – The Diminished Scales (not included): covers the Diminished half-whole scale (used over Dom 7 H9, nat 13 and the Diminished whole-half (used over Diminished 7 chords).

Chapter 5 – Singing Tetrachords over Harmony (not included): includes a rote exercise in all 12 keys designed to allow singers to pitch all six tetrachords from the same root over different sets of chord qualities. It’s also a good ear and voice warm up.

Chapter 6 – Singing scales using tetrachords over II, V, I, VI progression: I’ve included the preparation exercise only below (Ex9a) starting in the key of C (all 12 keys are included in the full exercise).

This exercise gives students the opportunity to apply what you’ve learned in the prior chapters by using the tetrachords in combination over a II, V, I, VI pattern with passing chords leading you to the next key. All the scales and associated chords should be familiar from the work done in the prior exercises. Before digging in, take a little time to familiarize yourself with the information included in the first two measures. Outside of the key notation, four (4) important pieces of information are provided on the stave for each event as follows:

  • Chord — the Roman Numeric sequence and the chord quality
  • Scale choice — stating both Parallel or Derivative options
  • Tetrachords — Bookend Tetrachords outlining the scale
  • Piano short cut —The use of slash/chords as an easier way of voicing a chord

Chapter Seven – Soloing over “Softly” chord changes (not included)

Chapter Eight – Pentatonic Scale Uses (not included)

Appendices #1 – #9 (not included)

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