C7#9

General info

Full name

C 7#9

Symbol

C7#9

Root

C

Quality

7#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

6A

b7A#

resolves down to the tonic 3rd

#2D#

4F

resolves to the resolution tonic

Main resolution

C7#9source

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

C7#9source

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.

C7#9source

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.

C7#9source

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.

C7#9source

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 an augmented 9th

Characteristic interval

Minor 7th (b7), Augmented 9th (#9)

Description

The augmented 9th is enharmonically equivalent to a minor 3rd and sounds alongside the chord’s major 3rd. Their chromatic clash creates sharp tension characteristic of blues and rock.

Application

• Blues rock (Jimi Hendrix "Purple Haze")
• Funk
• Jazz fusion

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.