1. Quartal Voicings Derived from Scales
A good way to begin to understand quartal voicings
is to play voicings based on scales. When first exploring jazz harmony,
students are often introduced to the idea of scale tone seventh chords, which
are tertian: chord voicings built in thirds. The two scales that are
best to begin with are the major and
melodic minor scales. These two scales set up the major and minor tonalities or
keys, and also serve as the basis for modes that are important in jazz.
Examples 3 and 4 give the scale tone seventh chords for C major and C melodic minor, respectively, and the chord qualities for each scale degree:
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Cma7 Dmi7 Emi7
Fma7 G7 Ami7
Bmi7b5 CMa7
Example 3:
Tertian Seventh Chord Voicings based on C Major Scale
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CmiMa7 Dmi7 EbMa7#5
F7 G7 Ami7b5
Bmi7b5 CmiMa7
Example 4: Tertian Seventh Chord Voicings based on C Melodic Minor Scale
These same scales also
allow for the formation of chord voicings based in fourths. These two scales
form a good introduction and context for understanding quartal voicings.
Examples 5 and 6 present quartal voicings based on the scales of C major and C
melodic minor, respectively:
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Example 5: Left Hand Quartal Voicings based on C Major Scale
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Example 6:
Left Hand Quartal Voicings based on C Melodic Minor Scale
Notice first that the chord voicings in Examples 3 and 4 are clear-cut and can be labeled in an unambiguous way. Although some chords can be interpreted in more than one way (for example, CMa7 could also be a rootless chord voicing for Ami9), the voicings are not as ambiguous as those in Examples 5 and 6. For example the first chord voicing in Example 5 (E, A, & D) could work for C6/9, Emi11, Ami11, Dmi9, Fma13, G13, Bmi11, and BbMa7b5. There are other possibilities.
Besides the ambiguity of modal music, the use of voicings in fourths also make the harmonies more ambiguous, but also more open. Moreover, as a result of their pure, clean, and open sound, the voicings simply sound great. Because of this, they are usable even when they are missing chord components that are considered important or even indispensable. For example, the second chord in Example 5 (F, B, & E) is a quartal chord voicing that would typically be used for Bmi7b5 (B half-diminished or BØ), even though the third (D) is missing. Moreover, it has the root: a chord voicing component that is typically avoided in left hand voicings.
The reverse approach—looking at a chord and realizing all of the possible quartal voicing approaches is perhaps the most valuable and productive application. In this case, the application of quartal voicings from a scale that the chord is related to leads to a variety of possibilities. For example, the C major scale will provide a variety of choices when choosing a chord voicing for CMaj7, C6, or C6/9. Moreover, since Cmaj7 is found in the keys of C and G, many quartal voicings from the G major scale will work. These include a total of seven voicings including three that include the #11 (Example 7):
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Example 7:
Left Hand Quartal Voicings for C Ma7, C6, & C6/9
Since the note F is not usable for a chord voicing for any C Major chord (i.e., Cmaj7, Cmaj9, C6, C6/9), three of the quartal voicings from the C major scale are unusable; the voicings in Example 7 are all found on the seven scale degrees of the G major scale. As a result, we end up with an entire scale of quartal voicings. Additionally, the same principle could be applied to other chords. For example, all of the above seven voicings are potentially usable for A min7, as well as other chords.
Accordingly, by practicing left hand quartal voicings through all major scales, we produce a vocabulary that blurs the distinction between chords and scales, and keys and modes. Chord choice is dependent on context, however, so the scale that serves as the harmonic foundation for the