# A♭ Suspended 4th piano chord (A♭sus4)

A♭sus4 contains A♭, D♭ and E♭. The third replaced by the fourth. Every note is a black key.

- Canonical page: https://piano.org/chords/suspended-4th/a-flat/
- Entity: chord:sus4:a-flat
- Notes: A♭ D♭ E♭
- Formula: 1 4 5
- Intervals from root: P1, P4, P5
- Interval stack (semitones): 5 2
- Also written: A♭sus4, Absus4, A♭ suspended 4th
- Parameters: A440, 12-TET, 165 mm octave, spans centre to centre

## Construction

| Degree | Note | Interval from root | Semitones |
| --- | --- | --- | --- |
| 1 | A♭ | Perfect unison | 0 |
| 4 | D♭ | Perfect fourth | 5 |
| 5 | E♭ | Perfect fifth | 7 |

## Fingering

Rest your right hand over the notes with finger 1 on A♭, finger 3 on D♭, finger 5 on E♭. The left hand mirrors it.
Right hand 1-3-5, left hand 5-3-1. Source: piano.org fingering method v1.

## Inversions

| Position | Bass | Notes in order | Figured bass | Span |
| --- | --- | --- | --- | --- |
| Root position | A♭ | A♭3 D♭4 E♭4 | 5/3 | 7 st, 96 mm |
| First inversion (A♭sus4/D♭) | D♭ | D♭4 E♭4 A♭4 | 6/3 | 7 st, 96 mm |
| Second inversion (A♭sus4/E♭) | E♭ | E♭4 A♭4 D♭5 | 6/4 | 10 st, 138 mm |

## Voicings (5)

| Voicing | Notes | Span | Relation | Omits or adds |
| --- | --- | --- | --- | --- |
| Close, root position | A♭3 D♭4 E♭4 | 7 st, 96 mm | identical | none |
| Close, first inversion | D♭4 E♭4 A♭4 | 7 st, 96 mm | identical | none |
| Close, second inversion | E♭4 A♭4 D♭5 | 10 st, 138 mm | identical | none |
| Open, fifth on top | A♭2 E♭3 D♭4 | 17 st, 234 mm | identical | none |
| Root and third only | A♭3 D♭4 | 5 st, 69 mm | subset | omits E♭ |

## One-edit neighbors

| Becomes | Edit | Changes | Common tones |
| --- | --- | --- | --- |
| A♭7sus4 | 1 4 5 ♭7 | adds G♭ | 3 |
| A♭ | 1 3 5 | D♭ becomes C | 2 |
| A♭m | 1 ♭3 5 | D♭ becomes C♭ | 2 |
| A♭sus2 | 1 2 5 | D♭ becomes B♭ | 2 |
| A♭maj7 | 1 3 5 7 | D♭ becomes C, G | 2 |
| A♭7 | 1 3 5 ♭7 | D♭ becomes C, G♭ | 2 |
| A♭m7 | 1 ♭3 5 ♭7 | D♭ becomes C♭, G♭ | 2 |
| A♭mMaj7 | 1 ♭3 5 7 | D♭ becomes C♭, G | 2 |
| A♭6 | 1 3 5 6 | D♭ becomes C, F | 2 |
| A♭m6 | 1 ♭3 5 6 | D♭ becomes C♭, F | 2 |
| A♭add9 | 1 3 5 9 | D♭ becomes C, B♭ | 2 |
| A♭dim | 1 ♭3 ♭5 | D♭, E♭ becomes C♭, E♭♭ | 1 |

## Set theory

- Absolute pitch classes: {8, 1, 3}
- Relative pitch classes: [0, 5, 7]
- Normal order: [1, 3, 8]
- Prime form: (027)
- Forte number: 3-9
- Interval vector: <010020>

## Frequencies (close root position)

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

## Questions and answers

### 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 &lt;010020&gt;.

### 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.

## Provenance

Every derived value above is computed by the piano.org theory kernel from the root, the quality and the stated parameters. Nothing is hand-entered per chord.

Machine record: https://piano.org/api/knowledge/v1/entities/chord:sus4:a-flat
Last reviewed: 2026-08-12