# A Suspended 2nd piano chord (Asus2)

Asus2 contains A, B and E. The third replaced by the second. Every note is a white key.

- Canonical page: https://piano.org/chords/suspended-2nd/a/
- Entity: chord:sus2:a
- Notes: A B E
- Formula: 1 2 5
- Intervals from root: P1, M2, P5
- Interval stack (semitones): 2 5
- Also written: Asus2, Asus2, A suspended 2nd
- Parameters: A440, 12-TET, 165 mm octave, spans centre to centre

## Construction

| Degree | Note | Interval from root | Semitones |
| --- | --- | --- | --- |
| 1 | A | Perfect unison | 0 |
| 2 | B | Major second | 2 |
| 5 | E | Perfect fifth | 7 |

## Fingering

Rest your right hand over the notes with finger 1 on A, finger 3 on B, 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 | A3 B3 E4 | 5/3 | 7 st, 96 mm |
| First inversion (Asus2/B) | B | B3 E4 A4 | 6/3 | 10 st, 138 mm |
| Second inversion (Asus2/E) | E | E4 A4 B4 | 6/4 | 7 st, 96 mm |

## Voicings (5)

| Voicing | Notes | Span | Relation | Omits or adds |
| --- | --- | --- | --- | --- |
| Close, root position | A3 B3 E4 | 7 st, 96 mm | identical | none |
| Close, first inversion | B3 E4 A4 | 10 st, 138 mm | identical | none |
| Close, second inversion | E4 A4 B4 | 7 st, 96 mm | identical | none |
| Open, fifth on top | A2 E3 B3 | 14 st, 193 mm | identical | none |
| Root and third only | A3 B3 | 2 st, 28 mm | subset | omits E |

## One-edit neighbors

| Becomes | Edit | Changes | Common tones |
| --- | --- | --- | --- |
| Aadd9 | 1 3 5 9 | adds C♯ | 3 |
| A | 1 3 5 | B becomes C♯ | 2 |
| Am | 1 ♭3 5 | B becomes C | 2 |
| Asus4 | 1 4 5 | B becomes D | 2 |
| Amaj7 | 1 3 5 7 | B becomes C♯, G♯ | 2 |
| A7 | 1 3 5 ♭7 | B becomes C♯, G | 2 |
| Am7 | 1 ♭3 5 ♭7 | B becomes C, G | 2 |
| AmMaj7 | 1 ♭3 5 7 | B becomes C, G♯ | 2 |
| A7sus4 | 1 4 5 ♭7 | B becomes D, G | 2 |
| A6 | 1 3 5 6 | B becomes C♯, F♯ | 2 |
| Am6 | 1 ♭3 5 6 | B becomes C, F♯ | 2 |
| Adim | 1 ♭3 ♭5 | B, E becomes C, E♭ | 1 |

## Set theory

- Absolute pitch classes: {9, 11, 4}
- Relative pitch classes: [0, 2, 7]
- Normal order: [9, 11, 4]
- Prime form: (027)
- Forte number: 3-9
- Interval vector: <010020>

## Frequencies (close root position)

| Note | MIDI | Frequency |
| --- | --- | --- |
| A3 | 57 | 220.00 Hz |
| B3 | 59 | 246.94 Hz |
| E4 | 64 | 329.63 Hz |

## Questions and answers

### What notes are in Asus2?

Asus2 contains A, B and E. The formula is 1, 2, 5.

### How do you play Asus2 on piano?

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

### What are the inversions of Asus2?

3 positions: root position A B E, Asus2/B, Asus2/E.

### What is the difference between Asus2 and Aadd9?

Adds C♯. 3 of the notes are shared.

### What is an easy Asus2 for small hands?

The root and third only voicing, A3 B3, spans 2 semitones or about 28 mm.

### What are the frequencies of Asus2?

From A3 at A440 in 12-TET: 220.00, 246.94, 329.63 Hz.

### What is the set class of Asus2?

Prime form (027), Forte 3-9, interval vector &lt;010020&gt;.

### How do I transpose Asus2 to another key?

Keep the 1, 2, 5 formula on the new root. Csus2 is C, D, G; C♯sus2 is C♯, D♯, G♯.

## 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:sus2:a
Last reviewed: 2026-08-12