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

A♯sus4 contains A♯, D♯ and E♯. The third replaced by the fourth. A♯ and D♯ are black keys; E♯ is white.

- Canonical page: https://piano.org/chords/suspended-4th/a-sharp/
- Entity: chord:sus4:a-sharp
- Notes: A♯ D♯ E♯
- Formula: 1 4 5
- Intervals from root: P1, P4, P5
- Interval stack (semitones): 5 2
- Also written: A♯sus4, A#sus4, 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: {10, 3, 5}
- Relative pitch classes: [0, 5, 7]
- Normal order: [3, 5, 10]
- Prime form: (027)
- Forte number: 3-9
- Interval vector: <010020>

## Frequencies (close root position)

| Note | MIDI | Frequency |
| --- | --- | --- |
| A♯3 | 58 | 233.08 Hz |
| D♯4 | 63 | 311.13 Hz |
| E♯4 | 65 | 349.23 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. A♯ and D♯ are black keys; E♯ is white.

### 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: 233.08, 311.13, 349.23 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 B♭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-sharp
Last reviewed: 2026-08-12