A-flat suspended fourth chord (Absus4)
The A♭ suspended fourth chord (A♭sus4) is a suspended chord: A♭, D♭ and E♭ (root, perfect fourth and perfect fifth). It has no third, so it is neither major nor minor.
It is the Isus4 in A♭ major and the Vsus4 in D♭ major, and it usually resolves to the major or minor chord on the same root.
Below: voicings, notes on the fretboard, ukulele, piano, inversions and progressions.
How to play A♭ suspended fourth on guitar
There are 2 guitar voicings.
Frets from the 6th string to the 1st: x = not played, 0 = open string.
- Voicing 1: 4-6-6-6-4-4, barre at fret 4, with A♭ in the bass (fingers 1-2-3-4-1-1).
- Voicing 2: x-11-13-13-14-11, movable A-shape barre chord at fret 11, with A♭ in the bass.
Notes of the A♭ suspended fourth chord on the fretboard
A♭ suspended fourth has 3 notes: A♭, D♭ and E♭. This is where they fall on each string, from the nut to the 12th fret (fret number in parentheses):
- String 6 (E): A♭ (4) · D♭ (9) · E♭ (11)
- String 5 (A): D♭ (4) · E♭ (6) · A♭ (11)
- String 4 (D): E♭ (1) · A♭ (6) · D♭ (11)
- String 3 (G): A♭ (1) · D♭ (6) · E♭ (8)
- String 2 (B): D♭ (2) · E♭ (4) · A♭ (9)
- String 1 (E): A♭ (4) · D♭ (9) · E♭ (11)
Formula and intervals of A♭ suspended fourth
Its formula is 1-4-5; in semitones from the root, 0-5-7.
- A♭: Root, the note that gives the chord its name
- D♭: Perfect fourth (P4), 5 semitones above A♭
- E♭: Perfect fifth (P5), 7 semitones above A♭
A♭ suspended fourth on ukulele
- Ukulele (G C E A): 1-3-4-4; it sounds A♭, E♭, A♭ and D♭.
A♭ suspended fourth on piano
- Keys: A♭4, D♭5 and E♭5.
Inversions of A♭ suspended fourth
Each inversion puts a different note in the bass.
- Root position: A♭, D♭ and E♭, with A♭ in the bass.
- First inversion (A♭sus4/D♭): D♭, E♭ and A♭, with D♭ in the bass.
- Second inversion (A♭sus4/E♭): E♭, A♭ and D♭, with E♭ in the bass.
Keys that use A♭ suspended fourth
A♭ suspended fourth appears in 10 major and minor keys.
| Key | Degree | Function |
|---|---|---|
| A♭ major (4 flats) | Isus4 | Tonic |
| G♭ major (6 flats) | IIsus4 | Supertonic |
| E major (4 sharps) | IIIsus4 (written G♯sus4) | Mediant |
| D♭ major (5 flats) | Vsus4 | Dominant |
| B major (5 sharps) | VIsus4 (written G♯sus4) | Submediant |
| G♯ minor (5 sharps) | Isus4 (written G♯sus4) | Tonic |
| F minor (4 flats) | IIIsus4 | Mediant |
| E♭ minor (6 flats) | IVsus4 | Subdominant |
| C♯ minor (4 sharps) | Vsus4 (written G♯sus4) | Dominant |
| B♭ minor (5 flats) | VIIsus4 | Subtonic |
Progressions with A♭ suspended fourth
- Sus4 resolution in A♭ major (Isus4–I): A♭sus4 – A♭
A♭ suspended fourth or G♯ suspended fourth?
A♭ suspended fourth (A♭sus4) and G♯ suspended fourth (G♯sus4) are the same chord with two names: they sound the same and use the same frets.
The spelling depends on the key: it is written A♭ suspended fourth in flat keys and G♯ suspended fourth in sharp keys.
Frequently asked questions
What notes are in the A♭ suspended fourth chord?
A♭, D♭ and E♭: root, perfect fourth and perfect fifth. Its formula is 1-4-5.
Which keys use A♭ suspended fourth?
Mainly as the Isus4 in A♭ major and the Vsus4 in D♭ major. In total it appears in 10 major and minor keys.
Is G♯ suspended fourth the same chord as A♭ suspended fourth?
Yes: G♯ suspended fourth and A♭ suspended fourth sound the same and are played the same way. It is written A♭ suspended fourth in flat keys and G♯ suspended fourth in sharp keys.
What does “sus” mean in A♭ suspended fourth?
That the chord is suspended: the third is replaced by another note, leaving A♭, D♭ and E♭ (root, perfect fourth and perfect fifth). Without a third, it can move to either the major or the minor triad on the same root.