Essential Jazz Chord Substitution Terms and Concepts

How do functional harmony and the circle of fifths influence the selection of substitute chords?

Functional harmony dictates that chords move in 5ths, providing a logical roadmap for substitution. By utilizing the circle of 5ths, you can replace a target chord with its dominant or subdominant, maintaining the 7-note diatonic structure while introducing fresh harmonic colors that still resolve toward the tonic.

What is the role of tritone substitution in dominant seventh chord progressions?

Tritone substitution replaces a dominant seventh chord with another dominant chord whose root is a tritone away, effectively sharing the same 3rd and 7th intervals to maintain resolution.

• Guide tones: The 3rd and 7th of the original chord become the 7th and 3rd of the substitute, creating a seamless transition.
• Root movement: Moving the root by a half-step downward creates a strong, chromatic pull toward the target tonic chord.
• Tension release: This method transforms a standard V-I cadence into a more modern-sounding bII-I resolution.
• Chromaticism: It introduces an unexpected harmonic flavor that adds sophisticated movement to otherwise predictable jazz standard progressions.

In what ways do secondary dominants function as substitutes within a diatonic sequence?

Secondary dominants act as temporary tonicizers that create a heightened sense of arrival by preceding a non-tonic chord with its own dominant.

1. Identify the target chord in a progression, such as a ii chord.
2. Calculate the perfect 5th above that target to find the secondary dominant.
3. Apply a dominant 7th quality to this new chord to establish a strong pull.
4. Optionally alter the 5th or 9th of the secondary dominant to increase tension.
5. Make sure the secondary dominant resolves directly to the target chord to maintain functionality.
6. Use these to turn a static diatonic sequence into a series of mini-cadences that drive the harmonic momentum forward.

How does the concept of chord quality—such as extended, altered, or diminished voicings—affect substitution viability?

Chord quality determines the available extensions and alterations that define whether a substitute will harmonize with the melody or create unwanted dissonance.

• Major 7th: These chords favor extensions like the 9th or 13th, making them poor substitutes for chords requiring sharp 11th tensions.
• Dominant 7th: These support altered tensions like the flat 9 or sharp 5, which are standard for tritone substitutions.
• Diminished 7th: These function as passing chords, allowing for symmetric movement that connects two chords a whole step apart.
• Extended voicings: Using a 9th or 11th chord often requires omitting the root to avoid cluttering the sound during complex substitutions.

What is the difference between diatonic substitution and chromatic substitution in jazz improvisation?

Diatonic substitution stays within the key signature to preserve tonal stability, whereas chromatic substitution introduces notes outside the scale to heighten tension.

Compare the number of non-diatonic notes in your chosen chord against the original to gauge how much tension you are introducing.

How do common tone substitutions allow for smooth voice leading between chords?

Common tone substitution relies on keeping one or more notes static while the surrounding voices move, which minimizes the perceived distance between chords. By anchoring a note, such as the 5th of a chord, you create a pivot point that guides the listener's ear through even the most radical harmonic shifts. For example, in a Cmaj7 to Abmaj7 progression, the note E acts as a common tone, allowing for a smooth transition despite the root movement being a major third away.

This technique is particularly effective for creating lush, orchestral textures in solo piano or guitar arrangements. However, a nuance exists regarding the melody: if the common tone is a dissonance against the new chord, it must be resolved carefully. Ignoring the relationship between the sustained note and the new chord's quality can result in unintended harshness, regardless of how well the roots connect.

What are the structural characteristics of a turnaround, and how are substitutions typically applied to them?

A turnaround typically consists of a four-bar progression, often I-vi-ii-V, designed to loop back to the start of a tune. Musicians apply substitutions by replacing the vi chord with a III7 or the ii chord with a bII7 to increase the chromatic drive toward the final V chord. Many people assume turnarounds must follow the I-vi-ii-V pattern strictly, but you can replace any of these chords with their tritone equivalents to radically alter the harmonic landscape while still landing safely on the tonic.

How do upper structure triads function as substitutes for complex extended jazz chords?

Upper structure triads allow you to imply complex 9th, 11th, or 13th chords by playing a simple triad over a different bass note. For instance, playing a D major triad over a G bass creates a G13 chord, effectively reducing 4-note complexity into a manageable 3-note structure.