A♭sus4: G♯/A♭ Suspended 4th Piano Chord

Root position: either hand, fingers low note to high
Hand	Notes	Fingers
Right	A♭, D♭, E♭	1-3-5
Left	A♭, D♭, E♭	5-3-1

Scale degree, note, and interval measured from the root.
Degree	Note	Interval from root	Semitones
1	A♭	Perfect unison	0
4	D♭	Perfect fourth	5
5	E♭	Perfect fifth	7

Construction

A♭ Suspended 4th = Root + Perfect 4th + Perfect 5th = A♭, D♭, E♭

Note	Interval	Degree
A♭	Root	1
D♭	Perfect 4th	4
E♭	Perfect 5th	5

Fingering

Note	Key color	Right hand	Left hand
A♭	black	thumb (1)	little finger (5)
D♭	black	middle finger (3)	middle finger (3)
E♭	black	little finger (5)	thumb (1)

Right hand: thumb (1) on A♭, middle finger (3) on D♭, little finger (5) on E♭.

Left hand: little finger (5) on A♭, middle finger (3) on D♭, thumb (1) on E♭.

A♭ Suspended 4th Inversions

Root position
A♭ – D♭ – E♭
1st inversion (A♭sus4/D♭)
D♭ – E♭ – A♭
2nd inversion (A♭sus4/E♭)
E♭ – A♭ – D♭

Key Signature

A Suspended 4th chord is built from symmetrical or ambiguous intervals, so it doesn't belong to a single key and has no key signature of its own.

Chords in the Key of A♭ Major

These are the triads built on each degree of A♭ Major:

I — A♭ Major (major)

Degree	Numeral	Chord	Quality
1	I	A♭ Major	Major
2	ii	B♭ Minor	Minor
3	iii	C Minor	Minor
4	IV	D♭ Major	Major
5	V	E♭ Major	Major
6	vi	F Minor	Minor
7	vii°	G Diminished	Diminished

Scales That Include the A♭ Suspended 4th

E Major (iii)
B Major (vi)
F# Major (ii)
Db Major (V)
Ab Major (I)
C# Minor (v)
G# Minor (i)
F Minor (III)

Same Notes, Other Names

The notes A♭ – D♭ – E♭ aren’t exclusive to this chord. Depending on which note is the bass and how the chord functions, the same pitches also spell:

C♯ Suspended 2nd→

A♭ Suspended 4th : Frequently Asked Questions

What notes are in A♭sus4?

A♭sus4 contains A♭, D♭ and E♭. The formula is 1, 4, 5.

How do you play A♭sus4 on piano?

Play A♭, D♭ and E♭ together. Right hand fingers 1, 3, 5; left hand 5, 3, 1. Every note is a black key.

What are the inversions of A♭sus4?

3 positions: root position A♭ D♭ E♭, A♭sus4/D♭, A♭sus4/E♭.

What is the difference between A♭sus4 and A♭7sus4?

Adds G♭. 3 of the notes are shared.

What is an easy A♭sus4 for small hands?

The root and third only voicing, A♭3 D♭4, spans 5 semitones or about 69 mm.

What are the frequencies of A♭sus4?

From A♭3 at A440 in 12-TET: 207.65, 277.18, 311.13 Hz.

What is the set class of A♭sus4?

Prime form (027), Forte 3-9, interval vector <010020>.

How do I transpose A♭sus4 to another key?

Keep the 1, 4, 5 formula on the new root. Csus4 is C, F, G; C♯sus4 is C♯, F♯, G♯.

Is G♯sus4 the same as A♭sus4?

Enharmonically yes: the same piano keys and the same sound, spelled differently.

A♭ Suspended 4th in detail

Exact

Every pitch class is present and nothing outside the chord is added.

Type	Notes	Semitones	Span	Omissions and additions	Set relation
Close, root position	A♭3 D♭4 E♭4	7	96 mm	none	identical
Close, first inversion	D♭4 E♭4 A♭4	7	96 mm	none	identical
Close, second inversion	E♭4 A♭4 D♭5	10	138 mm	none	identical
Open, fifth on top	A♭2 E♭3 D♭4	17	234 mm	none	identical

Reduced

A subset of the pitch classes: the identity is incomplete rather than altered.

Type	Notes	Semitones	Span	Omissions and additions	Set relation	Fit
Root and third only	A♭3 D♭4	5	69 mm	omits E♭	subset

Spans are measured centre to centre at a 165 mm octave (standard keyboard geometry).

Position	Bass note	Notes in order	Figured bass	Semitones	Span
Root position	A♭	A♭3, D♭4, E♭4	5/3	7	96 mm
First inversion: A♭sus4/D♭	D♭	D♭4, E♭4, A♭4	6/3	7	96 mm
Second inversion: A♭sus4/E♭	E♭	E♭4, A♭4, D♭5	6/4	10	138 mm

One position per chord tone in the bass. Spans are for close position: voiced inversions appear under Voicings.

Change one note

Chords a single note away, and what moving that note does.

Chord	Change	Formula	Common tones
A♭7sus4	adds G♭	1 4 5 ♭7	3
A♭	D♭ becomes C	1 3 5	2
A♭m	D♭ becomes C♭	1 ♭3 5	2
A♭sus2	D♭ becomes B♭	1 2 5	2
A♭maj7	D♭ becomes C, G	1 3 5 7	2
A♭7	D♭ becomes C, G♭	1 3 5 ♭7	2
A♭m7	D♭ becomes C♭, G♭	1 ♭3 5 ♭7	2
A♭mMaj7	D♭ becomes C♭, G	1 ♭3 5 7	2
A♭6	D♭ becomes C, F	1 3 5 6	2
A♭m6	D♭ becomes C♭, F	1 ♭3 5 6	2
A♭add9	D♭ becomes C, B♭	1 3 5 9	2
A♭dim	D♭, E♭ becomes C♭, E♭♭	1 ♭3 ♭5	1

Frequencies

Note	MIDI	Frequency
A♭3	56	207.65 Hz
D♭4	61	277.18 Hz
E♭4	63	311.13 Hz

Reference pitch A440, 12-TET, close root position.

Set theory: prime form, Forte number, interval vector

Absolute pitch class set: {8, 1, 3}
Normal order: [1, 3, 8]
Prime form: (027)
Forte number: 3-9
Interval vector: <010020>

Pair	Interval	Semitones	Interval class
A♭ to D♭	Perfect fourth	5	5
A♭ to E♭	Perfect fifth	7	5
D♭ to E♭	Major second	2	2

Where these facts come from

Every value on this page is derived from the note formula for a suspended 4th applied to the root A♭, using standard music theory. Nothing here is hand-entered per chord, so the notes, intervals, inversions and frequencies cannot drift out of agreement with each other. Pitches assume 12-TET at A440.

A♭ Suspended 4th

Fingerings

A♭ Suspended 4th: notes and degrees