A7b9

General info

Full name

A 7b9

Symbol

A7b9

Root

A

Quality

7b9

Chord notes

Functions & resolutions

Stability / tension

High tension — requires resolution

Most common resolutions

DD MajorBmB Minor

Unstable degrees

3C#

4D

resolves up to the resolution tonic

6F#

b7G

resolves down to the tonic 3rd

1A

b2A#

resolves down to the tonic 5th

Main resolution

A7b9source

DD Major

Dominant 7th A7 naturally resolves up a 4th to D. It is the tritone between the chord's 3rd and 7th that creates this pull.

Other resolutions

A7b9source

Deceptive resolution

BmB Minor

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

A7b9source

Modal resolution

GG Major

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

A7b9source

Jazz reharmonization

D#7D# Dominant 7

Tritone substitution: A7 can be replaced by D#7 (a tritone away). Both chords share the same tritone between the 3rd and 7th, resolving to the same tonic.

A7b9source

Functional resolution

Asus4A 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

Eb7Eb Dominant 7

Features

Character

Dominant, with minor-9th dissonance

Characteristic interval

Minor 7th (b7), Minor 9th (b9)

Description

The minor 9th forms a compound-semitone dissonance with the root, while the minor 7th preserves dominant function. On V in minor, b9 normally corresponds to scale degree 6 and resolves downward.

Application

• V7b9 → i in minor
• Flamenco and Latin jazz
• Minor jazz cadences

Voicing & structure

Harmony

Compatible scales

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