Questions: Extended Tertian Harmony and Upper-Extension Voice-Leading

Question 1

When voicing a dominant thirteenth chord (V13) in a jazz context, which tones are typically omitted first?

• A. The ninth and thirteenth — the most colorful extensions — to keep the voicing clean
• B. The fifth and often the root — the acoustically redundant tones
• C. The third and seventh — since those define chord quality, advanced chords don't need them
• D. The eleventh and thirteenth — the highest extensions are always the least essential

Answer: (B)

In jazz voicing practice, the fifth is acoustically implied by the root and third (through the overtone series) and is the first tone dropped. The root is often covered by the bass player and can also be omitted in a keyboard or guitar voicing. By contrast, the third and seventh define the chord's quality (major/minor/dominant) and must be retained. The ninth and thirteenth carry most of the coloristic extension — they are typically kept, not omitted. Option A represents the opposite of actual practice.

Question 2

The ninth of a dominant ninth chord (V9) tends to resolve in which direction?

• A. Up by step, because upper extensions always resolve upward toward the tonic
• B. Down by step, because the ninth sits above the root and tends to resolve downward
• C. It has no inherent tendency and can move freely in any direction
• D. By leap to the fifth of the tonic chord

Answer: (B)

The ninth of a dominant chord sits a step above the root (which resolves down to the leading tone of the following chord or stays). The ninth's resolution tendency is generally downward by step toward the octave or seventh of the resolving chord. This downward tendency is part of the general principle that upper extensions above the fifth resolve by step rather than leap, and that dominant-function chords resolve their 'active' tones downward toward the tonic harmony. The specific direction can vary with voicing and style, but downward is the default tendency.

Question 3

A Cmaj13 chord voicing is incomplete unless most seven chord tones — root, third, fifth, seventh, ninth, eleventh, and thirteenth — are present.

• T. True
• F. False

Answer: False

This is the central misconception about extended chords. A Cmaj13 chord contains seven distinct pitches, exceeding the capacity of most instruments and voices. Skilled voicing requires strategic omission: the fifth is acoustically redundant and omitted first; the root may be omitted if covered by the bass; the eleventh often clashes with the third unless raised. A voicing with third, seventh, ninth, and thirteenth — four notes — can be fully idiomatic and harmonically complete. Completeness in extended harmony is about capturing the chord's character, not its full literal stack.

Question 4

In extended chords, the fifth is often omitted because it is acoustically implied by the root and third through the overtone series.

• T. True
• F. False

Answer: True

The perfect fifth appears early in the overtone series of the root, and the interval relationship between root and third further implies the fifth through voice-leading expectations. Because the ear supplies the fifth contextually, including it in a dense voicing adds little information while consuming a voice that could carry a more colorful extension. This acoustic redundancy is why jazz pianists and guitarists routinely drop the fifth, while retaining the third, seventh, and desired extensions.

Question 5

What is the central challenge when voice-leading chords with multiple upper extensions? Why can't you simply apply the same resolution rules you use for seventh chords?

Model answer: Each upper extension introduces its own tendency tone pulling in a specific direction: the seventh resolves down, the ninth resolves down by step, the thirteenth tends to resolve up to the tonic. With multiple extensions stacked above the same chord, you have several active tones competing for voice-leading clarity within a limited number of voices. Seventh chord rules handle one active tone (the seventh); extended chords require managing simultaneous, sometimes conflicting resolution tendencies.

The craft challenge is balancing these competing tendencies within practical voicing constraints. In jazz, this is often resolved through selective omission — keeping only the most structurally important extensions — and through idiomatic voicings that allow extensions to resolve implicitly rather than explicitly. Classical composers like Debussy suspended these resolutions deliberately, treating the extensions as color rather than tendency. Both approaches are valid; the key insight is that the rules don't scale mechanically from seventh chords to thirteenth chords.