B9b5

Q: What notes are in the B9b5 chord?

The B9b5 chord (B 9b5) contains: B, D#, F, A, C#. Its interval structure is shown above in the Theory section.

Q: How do I build B9b5 on the keyboard?

Take the root and add the remaining chord tones following the interval formula. The highlight shows chord content, while the inversion control changes which chord tone is in the bass.

Q: Which keys is B9b5 found in?

The chord acts as a diatonic degree in several keys — they are marked on the circle of fifths in the "Harmonic context" block.

Q: What can I substitute for B9b5?

A substitution depends on harmonic function and voice leading, not only on shared tones. Computed options appear in the "Substitutions" block and should be checked in context.

B 9b5

Octaves

Musical context

ChordB majorTriad

ChordB9b5B 9b5

ArpeggioB majorBroken triad

ScaleB major7 notes

KeyB majorMajor key

ProgressionPop axisSequence

How the chord relates to the scale, mode, key and progression.

Theory

General info

Full name: B 9b5
Symbol: B9b5
Root: B
Quality: 9b5

Chord notes

1Broot

3D#major 3rd

b5Fdim 5th

b7Aminor 7th

2C#major 2nd

Functions & resolutions

Stability / tension: High tension — requires resolution
Most common resolutions: EE Major C#mC# Minor
Unstable degrees: 3D#
4E
resolves up to the resolution tonic
4E
b5F
resolves inward to the resolution tonic
6G#
b7A
resolves down to the tonic 3rd
Main resolution: B9b5source
EE Major
Dominant 7th B7 naturally resolves up a 4th to E. It is the tritone between the chord's 3rd and 7th that creates this pull.
Other resolutions: B9b5source
Deceptive resolution
C#mC# Minor
Instead of the tonic, the dominant resolves to the vi degree. Creates surprise and is often used to extend a musical phrase.
B9b5source
Modal resolution
AA Major
In rock and blues, the dominant often moves to bVII or IV instead of the tonic, creating a modal flavor.
B9b5source
Jazz reharmonization
F7F Dominant 7
Tritone substitution: B7 can be replaced by F7 (a tritone away). Both chords share the same tritone between the 3rd and 7th, resolving to the same tonic.
B9b5source
Functional resolution
Bsus4B 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: F7F Dominant 7

Features

Character: Dominant, with 9th and diminished 5th
Characteristic interval: Diminished 5th (b5), 9th
Description: The minor 7th establishes the dominant structure, the 9th extends it, and the diminished 5th adds a second tritone against the root. The chord is more dissonant than a regular 9.
Application: Tritone sub with ninth
Jazz and fusion
Improvising over Lydian dominant

Voicing & structure

Root position

v1B(B4)Bass

root

v2D#(D#5)M3from B

v3F(F5)M2from D#

v4A(A5)M3from F

v5C#(C#6)M3from A

Harmony

Compatible scales

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

ScaleC# Whole tone scale ScaleD# Whole tone scale ScaleF Whole tone scale ScaleA Whole tone scale ScaleB Whole tone scale ScaleG Whole tone scale ScaleC# Mixolydian ♭6 ScaleF Enigmatic scale ScaleF Altered (super Locrian)ScaleA Lydian augmented

This chord on guitar 🎸

See how B9b5 looks on guitar.

Explore

Circle of fifths

Highlighted major keys contain this chord among their diatonic harmonies.

Relative key: G#mG# minor
Dominant: F#F# major
Subdominant: EE major
Key signature: 5 sharps (F#, C#, G#, D#, A#)

What to learn next

ScaleB Chromatic scaleScale to improvise over this chord PracticeChord trainerLock the fingering into muscle memory ProgressionChord progressionsHow this chord works inside real progressions

Recommended for you

B Chromatic scaleA scale related to this chord

Practice

Keyboard Trainer

Reinforce it in practice — play and name notes on the interactive keyboard.

Open Trainer

Test yourself

(Press any key to start)

What notes are in the B9b5 chord?

How do I build B9b5 on the keyboard?

Which keys is B9b5 found in?

What can I substitute for B9b5?