Jazz Reharmonization Terms You Need to Know

What is the functional difference between diatonic and chromatic substitution?

Diatonic substitution replaces a chord with another that shares the same function within the home key, whereas chromatic substitution introduces non-diatonic notes to intensify the pull toward a target. Diatonic changes preserve the tonal center, while chromatic changes temporarily obscure it to create heightened directional energy.

Use these categories to gauge how much dissonance you are injecting into a standard progression.

How do secondary dominants and extended dominants facilitate harmonic movement?

Secondary dominants act as temporary magnets, pulling the ear toward a specific chord that isn't the tonic. By inserting a V7 chord a perfect fifth above the target, you create a momentary sense of arrival. For example, in a progression moving from C major to A minor, inserting an E7 before the A minor creates a strong cadential pull. This technique transforms static passages into active, forward-moving sequences.

Extended dominants take this further by stacking intervals like 9ths, 11ths, and 13ths onto the V7 chord. These extensions provide harmonic density without losing the fundamental function of the dominant. A crucial nuance exists here: if you extend a dominant chord too far, you risk obscuring the root movement, which can confuse the soloist. Always make sure the 3rd and 7th of the chord remain clear, as these guide tones define the resolution.

What role do tritone substitutions play in altering the tension of a chord progression?

Tritone substitutions replace a dominant chord with one whose root is three whole steps away, utilizing the shared tritone interval between the 3rd and 7th of both chords to maintain resolution. This swap introduces a descending chromatic bass line that feels more modern and fluid than standard root motion. Many musicians assume that a tritone sub changes the function of the chord, but the function remains identical; it still serves as a dominant that must resolve down a half-step to the tonic.

In what ways does the concept of voice leading influence the choice of chord voicings during reharmonization?

Voice leading dictates that individual notes within a chord progression should move by the smallest possible interval to maintain melodic continuity between harmonic shifts.

1. Keep common tones stationary to anchor the listener's ear during a chord change.
2. Move inner voices by half-steps to create smooth, chromatic connections between chords.
3. Avoid large leaps in the bass line to make sure the foundation remains stable.
4. Resolve the tritone interval within dominant chords inward or outward by a half-step to satisfy the ear's expectation.
5. Use contrary motion between the bass and soprano lines to increase the independence of the voices.

How can modal interchange be utilized to introduce new harmonic colors to a standard progression?

Modal interchange involves borrowing chords from a parallel key, such as using the minor iv chord in a major key progression. This technique provides a sudden shift in mood, often described as a darker or more melancholic color within a bright, major-key environment. By pulling chords from the parallel minor, you gain access to the flat-sixth and flat-seventh degrees, which are not available in the standard major scale.

For instance, in the key of C major, replacing the F major chord with an F minor chord creates a classic, bittersweet resolution to the C major tonic. A common nuance to remember is that modal interchange works best when the borrowed chord retains a clear relationship to the home key's tonic. If the borrowed harmony is too distant, it may sound like a modulation rather than a subtle color change.

What are the primary characteristics of passing chords and how are they implemented to bridge harmonic gaps?

Passing chords function as connective tissue, filling the rhythmic space between two primary harmonic landmarks. These chords typically last for only 1 or 2 beats. By using diminished 7th chords or chromatic approaches, they create a sense of momentum that prevents the progression from feeling static or overly predictable.

How does the application of slash chords change the harmonic function of a bass line?

Slash chords alter the harmonic function by decoupling the chord's identity from its root, allowing the bass line to move independently of the upper structure.

• Pedal point: A sustained note in the bass creates a static foundation while the chords above change, building immense tension.
• Inversion: A chord with a non-root note in the bass provides a smoother, more melodic path for the bottom end.
• Chromaticism: A bass line moving by half-steps using slash chords creates a sophisticated, linear drive that supports complex soloing.
• Counterpoint: A bass line that moves in contrary motion to the melody adds depth and independence to the arrangement.

What distinguishes 'reharmonization' from 'substitution' in the context of jazz improvisation?

Reharmonization involves rewriting the entire harmonic structure of a tune, often changing 50% or more of the original chords. Substitution is a smaller, local change where one chord is swapped for another of the same function. Both techniques rely on the same underlying principles of functional harmony.