Questions to Ask When Researching Jazz Altered Chords

How are altered dominant chords derived from the melodic minor scale?

The altered scale is the seventh mode of the melodic minor scale, starting a half-step above the root of the dominant chord. For a G7alt chord, you play the A-flat melodic minor scale. This arrangement naturally places the b9, #9, #11, and b13 tensions over the dominant root. Many players assume the altered scale is just a collection of random dissonances, but it is a highly logical, symmetrical structure that functions as a specific set of voice-leading tendencies toward the tonic.

What are the specific interval structures of the most common altered chord qualities, such as 7alt, 7(b9), and 7(#9)?

These chords are constructed by stacking specific altered tensions onto the basic dominant seventh shell of root, third, and seventh.

• 7alt: Includes the b9, #9, #11, and b13, creating a dense, highly unstable sound that demands immediate resolution.
• 7(b9): Features only the flat nine, often used in minor ii-V-I progressions to provide a darker, more contained tension.
• 7(#9): Employs the sharp nine, frequently associated with the "Hendrix chord" sound, providing a bluesy, aggressive bite without the extra dissonance of the flat thirteen.
• 7(b9, b13): Combines the flat nine and flat thirteen, a common choice for smooth, sophisticated voice leading in jazz balladry.

How do altered chords function within the context of a ii-V-I progression?

In a ii-V-I progression, the altered chord functions as the primary engine of harmonic momentum, replacing the standard dominant to increase the pull toward the tonic. By introducing these tensions, you create a stronger need for resolution because the altered notes are non-diatonic to the home key. For example, in the key of C major, a G7(b9, b13) creates a powerful gravitational force that makes the arrival on the Cmaj7 chord feel inevitable and satisfying.

One nuance involves the placement of these chords in longer cycles. While they are common in standard ii-V-I patterns, you might avoid them in sequences where the dominant chord lasts for many bars. In those cases, keeping the harmony static or using a mixolydian sound for longer periods prevents the listener from experiencing "tension fatigue," where the constant dissonance loses its impact and starts to sound like aimless noise.

What are the best voice-leading strategies for resolving altered chords to their tonic targets?

Effective resolution relies on moving the tension notes by the smallest possible interval to reach the nearest stable chord tone of the target tonic.

• Half-step: Move the flat nine down a half-step to the fifth of the tonic chord.
• Whole-step: Shift the sharp nine down a whole-step to the root of the tonic chord.
• Chromatic: Lead the flat thirteen down a half-step to the fifth of the tonic chord.
• Direct: Resolve the sharp eleven down a half-step to the third of the tonic chord.

Which specific scale degrees are modified in the altered scale to create tension?

Yes, the altered scale modifies the second, third, fifth, and sixth degrees of the major scale. Specifically, it flattens the 9th, 13th, and 5th, while sharpening the 9th and 11th to create four distinct altered tensions that push forcefully toward the target chord's tones.

How do jazz pianists and guitarists typically voice altered chords to emphasize the tension notes?

Pianists and guitarists emphasize altered tensions by using "shell voicings" that omit the root and fifth, focusing instead on the third, seventh, and the specific altered extensions. By placing the b9 or #9 in the upper register of the chord, the player makes sure that the tension is the most audible element. A common technique involves playing the 3rd and 7th in the left hand while the right hand strikes a cluster of tensions, such as a triad built off the b9, to highlight the color.

A notable exception occurs when the melody itself contains one of the altered notes. In such instances, the accompanist must be careful not to double the melody note with a conflicting tension in the chord voicing. This creates a muddy texture that obscures the clarity of the line, so the player should adjust their voicing to support the melody rather than competing with it.

In what ways do altered chords differ from standard dominant seventh chords in terms of harmonic function?

Altered chords function as high-intensity substitutes for standard dominants, designed to maximize the harmonic drive toward a resolution point.

1. Identify the target tonic chord to determine which altered tensions will resolve most smoothly.
2. Replace the natural 9th or 13th of a standard dominant with the b9, #9, or b13.
3. Keep the 3rd and 7th of the dominant chord intact to maintain the essential "tritone" pull.
4. Voice the altered tensions in the upper register to make sure they stand out against the fundamental chord tones.
5. Resolve each tension note by moving it to the closest available degree of the target tonic.

Are there specific historical jazz recordings that effectively demonstrate the application of altered chords?

Yes, recordings like the 1957 album Blue Train by John Coltrane demonstrate the sophisticated application of these sounds. The title track highlights how the altered dominant functions within complex bebop lines, providing the necessary harmonic friction that makes the eventual resolution to the tonic feel earned and structurally sound.