Key Terms for Jazz Altered Chords Explained

What is the functional role of a dominant seventh chord in jazz harmony?

The dominant seventh chord functions as a harmonic engine, creating an unstable state that demands movement toward a stable tonic chord. Its primary role is to establish a key center through the resolution of the tritone interval found between the third and seventh degrees. Many listeners assume that all dominant seventh chords must resolve to a tonic a perfect fourth higher, but in practice, they frequently resolve to chords a half-step away or even to other dominant seventh chords in deceptive or chromatic progressions.

How do tension and release mechanisms operate within altered dominant chords?

These chords utilize chromatic alterations to maximize the distance from a stable tonic, creating an intense gravitational pull that forces the harmony to resolve.

• b9 and #9: These tones introduce harsh, dissonant clusters against the root, creating a sense of urgency that necessitates an immediate release.
• #11: This interval acts as a colorful, suspended sound that destabilizes the chord's tonal center, making the eventual arrival at a stable triad feel more satisfying.
• b13: By lowering the fifth, this tone adds a dark, melancholic quality that bridges the gap between the dominant chord and the target resolution.
• Resolution: The release occurs when these tense, non-diatonic notes move by half-step to the stable chord tones of the following tonic.

Which specific scale degrees are modified to create an altered chord quality?

Yes, the 5th and 9th scale degrees are the primary targets for modification. By sharpening or flattening these specific degrees, you create the altered dominant sound. For example, the 5th can be raised or lowered, while the 9th offers two distinct altered options, totaling four possible chromatic variations.

How does the altered scale relate to the melodic minor scale?

The altered scale is essentially the seventh mode of the melodic minor scale, starting a half-step above the root of the dominant chord. For a G7 altered chord, you play the Ab melodic minor scale. This relationship provides a convenient shortcut for improvisers, as it allows them to access all four primary alterations—the b9, #9, #11, and b13—without needing to memorize them as isolated, disconnected intervals.

One nuance is that while the scale contains these alterations, it lacks a natural 5th, which is often avoided to maintain the chord's specific color. An exception exists when a musician chooses to emphasize the natural 5th for a more traditional, bebop-oriented sound, which technically shifts the harmony away from the pure altered scale and into the realm of mixolydian b6 or other hybrid scales.

What is the significance of the tritone interval in the construction of altered chords?

The tritone serves as the harmonic foundation of the dominant seventh chord, acting as the primary source of dissonance that pushes the music forward.

• 3rd and 7th: These two notes form the core tritone, creating the inherent instability that requires a resolution to the tonic.
• b5 and 7th: In an altered context, the flattened fifth creates a new tritone against the root, intensifying the drive toward the resolution.
• #11: This note functions as a surrogate for the natural 5th, further destabilizing the chord by creating a tritone relationship with the root.
• Resolution: The two voices of the tritone move in contrary motion, typically inward or outward by half-steps, to land on the essential notes of the tonic chord.

How do jazz musicians utilize voice leading to connect altered chords to their resolutions?

Voice leading relies on moving altered notes by a single half-step to reach stable chord tones. For instance, the #9 of a G7 chord, which is Bb, resolves down to the A, the 5th of a C major triad, ensuring a smooth, logical transition between harmonies.

What are the common upper extensions and alterations found in jazz chord symbols?

Jazz chord symbols use specific shorthand to communicate complex harmonic structures, distinguishing between extensions that add color and alterations that add tension. Extensions like the 9, 11, and 13 are derived from the diatonic scale, while alterations like #9 or b13 signal that the chord is pulling heavily toward a resolution. A symbol like G7(b9, #11) tells a player exactly which notes to modify to achieve the desired dissonance.

A common nuance is the distinction between the #11 and the natural 11. While the natural 11 is often avoided on dominant chords because it clashes with the major third, the #11 is a staple of the lydian dominant sound. Musicians must be careful to interpret these symbols based on the context of the progression, as the player's ear often dictates whether to include or omit the natural 5th or 9th.

How does the concept of chord-scale theory simplify the improvisation process over altered harmonies?

Chord-scale theory allows improvisers to associate a specific parent scale with a chord, streamlining the selection of notes that sound coherent over complex harmonies.

Focus on the unique notes in each scale to define the harmonic color during your solo.