Bb7b9

General info

Full name

Bb 7b9

Symbol

Bb7b9

Root

Bb

Quality

7b9

Chord notes

Functions & resolutions

Typical function in key

VDominant (V)Eb major

Stability / tension

High tension — requires resolution

Most common resolutions

EbEb MajorCmC Minor

Unstable degrees

3D

4Eb

resolves up to the resolution tonic

6G

b7Ab

resolves down to the tonic 3rd

1Bb

b2B

resolves down to the tonic 5th

Main resolution

Bb7b9source

EbEb Major

Dominant 7th Bb7 naturally resolves up a 4th to Eb. It is the tritone between the chord's 3rd and 7th that creates this pull.

Other resolutions

Bb7b9source

Deceptive resolution

CmC Minor

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

Bb7b9source

Modal resolution

AbAb Major

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

Bb7b9source

Jazz reharmonization

E7E Dominant 7

Tritone substitution: Bb7 can be replaced by E7 (a tritone away). Both chords share the same tritone between the 3rd and 7th, resolving to the same tonic.

Bb7b9source

Functional resolution

Bbsus4Bb 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

E7E 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.