Jazz Chord Substitution Examples for Better Reharmonization

How does the tritone substitution function within a ii-V-I progression?

A tritone substitution replaces a dominant chord with one whose root is three whole steps away, effectively maintaining the original chord's resolution while adding chromatic interest to the ii-V-I sequence.

• Root movement: The bass line descends by a half-step, such as moving from Db7 to Cmaj7, which provides a smoother, more modern resolution than the standard perfect fifth leap.
• Common tones: The 3rd of the G7 chord is B, which acts as the b7 of the Db7 chord, and the b7 of G7 is F, which serves as the 3rd of Db7.
• Tension levels: The substitution introduces a flattened second degree, creating a sophisticated pull toward the tonic that sounds less predictable to the ear.

What is the theoretical relationship between a dominant seventh chord and its tritone substitute?

The relationship relies on the shared tritone interval between the 3rd and 7th of both chords. In a G7 chord, the interval between B and F is six semitones, which is identical to the interval between F and Cb in a Db7 chord.

In what ways do secondary dominants facilitate harmonic movement in jazz standards?

Secondary dominants create a temporary sense of arrival by applying a dominant seventh chord to any target chord other than the tonic.

1. Identify the target chord, such as a ii chord in a major key.
2. Calculate the perfect fifth above that target to find the root of the secondary dominant.
3. Alter the quality of the new chord to a dominant seventh, regardless of the original scale degree.
4. Resolve the secondary dominant into the target chord to establish a localized, strong harmonic pull.
5. Use this technique to transform a static progression into a series of interconnected cadences that propel the listener toward the next section of the song.

How can diatonic substitution be used to reharmonize a basic melody?

Diatonic substitution replaces a chord with another that shares at least two of the same notes, allowing for a change in color without breaking the underlying key signature.

• Relative minors: Replacing a I chord like Cmaj7 with its relative minor, Am7, preserves the tonic function while shifting the mood from bright to melancholic.
• Subdominant pairs: Swapping Fmaj7 for Dm7 works because both chords share the notes F, A, and C, keeping the harmonic foundation stable.
• Chord extensions: Adding a 9th or 13th to a diatonic chord creates a denser texture that remains compatible with the original melody notes.
• Functional overlap: Using Em7 instead of Cmaj7 maintains the tonic sound while providing a softer, less definitive landing point.

What role does voice leading play in making chord substitutions sound natural?

Voice leading makes sure that individual notes within a chord progression move by the smallest possible distance, preventing the jarring effect of wide leaps. When substituting a chord, the goal is to keep common tones stationary or move them by a single step. For example, when moving from Dm7 to G7, the C in the Dm7 can resolve downward to the B in the G7, creating a smooth, linear connection that the ear perceives as logical and satisfying.

A common exception occurs in jazz styles that prioritize rhythmic punch over smooth melodic lines, such as in certain bebop heads or funk-influenced arrangements. In these cases, composers may intentionally use wider leaps to emphasize the percussive nature of the rhythm section. This approach sacrifices traditional voice leading to achieve a more aggressive, angular sound that highlights the syncopation of the performance.

How do diminished seventh chords function as passing chords between diatonic harmonies?

Diminished seventh chords act as chromatic bridges that connect two diatonic chords separated by a whole step. By placing a C#dim7 between a Cmaj7 and a Dm7, you create a half-step motion that resolves into the next chord, effectively smoothing out the harmonic transition.

What is the difference between functional and non-functional chord substitution?

Functional substitution preserves the root movement and resolution tendencies of the original progression, whereas non-functional substitution ignores these rules for the sake of color or surprise.

Use these categories to decide if you need to maintain the original bass movement or if you are free to experiment with static textures.

How can the concept of 'chord quality' be maintained while swapping chords in a progression?

Maintaining chord quality involves ensuring that the substituted chord functions within the same harmonic family as the original, such as swapping a major seventh for a major sixth or a ninth. This keeps the character of the progression intact while offering subtle variations in color. For instance, replacing a Cmaj7 with a C6 chord retains the stability of the tonic while removing the slightly dissonant major seventh interval, which can make the harmony sound warmer and more settled.

One nuance to consider is that changing the chord quality can sometimes alter the intended tension of a section. If a melody relies heavily on the specific tension of a major seventh note, replacing that chord with a major sixth may cause the melody to sound slightly out of place. It is essential to verify that the substituted chord quality supports the melody rather than conflicting with the intended emotional weight of the phrase.