A Suspended 4th Chord
Chord Tones: A Suspended 4th Chord
Symbol: sus4, sus — Formula: 1-4-5
| Degree | Note | Frequency (A=440, Equal) |
|---|---|---|
| 1 | A | 440.000 Hz |
| 4 | D | 293.665 Hz |
| 5 | E | 329.628 Hz |
Chord Notation
| Notation Type | Symbol / Value |
|---|---|
| Lead Sheet Symbol | Asus4 |
| All Common Symbols | sus4, sus |
| Interval Formula | 1-4-5 |
| Harmonic Category | open |
Roman numeral (e.g. I, IV, V) and Nashville Number notation are key-dependent. See Keys pages for chord function within specific keys.
Inversions
| Inversion | Notes (low to high) | Bass Note | Slash Notation |
|---|---|---|---|
| Root Position | A – D – E | A | A Suspended 4th Chord |
| First Inversion | D – E – A | D | A Suspended 4th Chord/D |
| Second Inversion | E – A – D | E | A Suspended 4th Chord/E |
Harmonic Function
The A sus4 chord commonly functions as the submediant (vi) in C major or dominant (V) in D major. Its harmonic role varies by key — in major keys it provides stable harmonic grounding.
The sus4 chord replaces the third with a perfect fourth, creating tension that traditionally resolves down to the major third. It creates anticipation and is common before dominant chords.
Common Progressions
The A Suspended 4th Chord frequently appears in these progression patterns (shown in Roman numeral notation relative to key):
Vsus4-V-IIsus4-I
Songs Featuring the Suspended 4th Chord
Well-known songs where the A Suspended 4th Chord — or this chord type — plays a prominent role:
- Scarborough Fair – Simon & Garfunkel
- The Seeker – The Who
- Born on the Bayou – CCR
Tuning Frequencies Across Temperaments
Frequencies shown at A=440 Hz. View full temperament data for any note.
| Note | Equal Temp. | Pythagorean | Just Intonation |
|---|---|---|---|
| A | 440.000 Hz | 440.000 Hz | 436.043 Hz |
| D | 293.665 Hz | 293.332 Hz | 294.329 Hz |
| E | 329.628 Hz | 330.001 Hz | 327.032 Hz |
Scales Containing the A Suspended 4th Chord
These scales include the A Suspended 4th Chord as a diatonic or characteristic chord: