Caug9

General info

Full name

C Aug 9

Symbol

Caug9

Root

C

Quality

Aug 9

Chord notes

Functions & resolutions

Stability / tension

High tension — requires resolution

Most common resolutions

FF MajorDmD Minor

Unstable degrees

3E

4F

resolves up to the resolution tonic

#5G#

6A

resolves up to the tonic 3rd

6A

b7A#

resolves down to the tonic 3rd

Main resolution

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FF Major

Dominant 7th C7 naturally resolves up a 4th to F. It is the tritone between the chord's 3rd and 7th that creates this pull.

Other resolutions

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Deceptive resolution

DmD Minor

Instead of the tonic, the dominant resolves to the vi degree. Creates surprise and is often used to extend a musical phrase.

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Modal resolution

A#A# Major

In rock and blues, the dominant often moves to bVII or IV instead of the tonic, creating a modal flavor.

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Jazz reharmonization

F#7F# Dominant 7

Tritone substitution: C7 can be replaced by F#7 (a tritone away). Both chords share the same tritone between the 3rd and 7th, resolving to the same tonic.

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Functional resolution

Csus4C Sus4

The dominant can resolve beyond the tonic: moving to IV (subdominant) or to a suspension (sus4) are common alternatives in pop and folk music.

Substitutions

Tritone substitution

F#7F# Dominant 7

Features

Character

Dominant, with 9th and augmented 5th

Characteristic interval

Augmented 5th (#5), 9th

Description

The augmented 5th destabilises the triadic core, the minor 7th preserves dominant function, and the major 9th extends the chord. The #5 alteration intensifies chromatic voice leading.

Application

• V+ → I in jazz
• Altered blues
• Passing chords

Voicing & structure

Harmony

Typical progressions

I-V-vi-IV

C—G—Am—F

Pop

Compatible scales

All chord tones are contained in these scales — use them for improvisation.