Faug9

Q: What notes are in the Faug9 chord?

The Faug9 chord (F Aug 9) contains: F, A, C#, Eb, G. Its interval structure is shown above in the Theory section.

Q: How do I build Faug9 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 Faug9 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 Faug9?

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.

F Aug 9

Octaves

Musical context

ChordFaugTriad

ChordFaug9F Aug 9

ArpeggioF majorBroken triad

ScaleF major7 notes

KeyF majorMajor key

ProgressionPop axisSequence

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

Theory

General info

Full name: F Aug 9
Symbol: Faug9
Root: F
Quality: Aug 9

Chord notes

1Froot

3Amajor 3rd

#5C#aug 5th

b7Ebminor 7th

2Gmajor 2nd

Functions & resolutions

Stability / tension: High tension — requires resolution
Most common resolutions: BbBb Major GmG Minor
Unstable degrees: 3A
4Bb
resolves up to the resolution tonic
#5Db
6D
resolves up to the tonic 3rd
6D
b7Eb
resolves down to the tonic 3rd
Main resolution: Faug9source
BbBb Major
Dominant 7th F7 naturally resolves up a 4th to Bb. It is the tritone between the chord's 3rd and 7th that creates this pull.
Other resolutions: Faug9source
Deceptive resolution
GmG Minor
Instead of the tonic, the dominant resolves to the vi degree. Creates surprise and is often used to extend a musical phrase.
Faug9source
Modal resolution
EbEb Major
In rock and blues, the dominant often moves to bVII or IV instead of the tonic, creating a modal flavor.
Faug9source
Jazz reharmonization
B7B Dominant 7
Tritone substitution: F7 can be replaced by B7 (a tritone away). Both chords share the same tritone between the 3rd and 7th, resolving to the same tonic.
Faug9source
Functional resolution
Fsus4F 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: B7B 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

Root position

v1F(F4)Bass

root

v2A(A4)M3from F

v3C#(C#5)M3from A

v4Eb(Eb5)M2from C#

v5G(G5)M3from Eb

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

This chord on guitar 🎸

See how Faug9 looks on guitar.

Explore

Circle of fifths

Highlighted major keys contain this chord among their diatonic harmonies.

Relative key: DmD minor
Dominant: CC major
Subdominant: BbBb major
Key signature: 1 flat (Bb)

What to learn next

ScaleF 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

F Chromatic scaleA scale related to this chord

Practice

Keyboard Trainer

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

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Test yourself

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What notes are in the Faug9 chord?

How do I build Faug9 on the keyboard?

Which keys is Faug9 found in?

What can I substitute for Faug9?