Piano Diagram of A#sus4 in Root Position
The A# suspended fourth (A#sus4) chord consists of three notes: A#, D#, and E# (which is equivalent to F). It’s called a “suspended 4” chord because the third note of the chord is replaced with a perfect fourth. To play the A#sus4 chord on a piano, you would start with an A# major chord and replace the third note, which is Cx (C “double sharp,” equivalent to D), with the fourth note, which is D#. Further reading will give you a better understanding of the music theory principles behind this chord.
Structure of A#sus4
Notes |
|---|
| A#, D#, E# |
Intervals |
|---|
| R, 4, 5 |
Fingers Position
Left Hand |
|---|
| 4, 2, 1
5, 2, 1 |
Right Hand |
|---|
| 1, 3, 4
1, 4, 5 |
A#sus4 Chord Inversions
The A#sus4 chord has a total of 2 inversions:
| Root Position: | A# | D# | E# |
| 1st Inversion: | D# | E# | A# |
| 2nd Inversion: | E# | A# | D# |
Piano Keyboard Diagrams
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- A#sus4 Chord – Root Position
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- A#sus4 Chord – 1st Inversion
-
- A#sus4 Chord – 2nd Inversion
A#sus4 Chord Equivalencies
An interesting detail about sus4 chords is that their 1st inversion results in a sus2 chord. To clarify, when the 4th note of a sus4 chord becomes the root note, it transforms into a sus2 chord.
1st Inversion of A#sus4 = D#sus2
For instance, if we take the A#sus4 chord with the notes A#, D#, and E# and rearrange them so that D# becomes the root note, we end up with a D#sus2 chord with the notes D#, E#, and A#. Therefore, the 1st inversion of A#sus4 is equivalent to D#sus2.
Music Theory and Harmony of A#sus4
What are Suspended Chords?
Suspended chords are a type of chord in which the third note is replaced by either a major second or a perfect fourth. These resulting chords are called suspended second (sus2) or suspended fourth (sus4) chords, respectively. These chords create a unique and sometimes unresolved sound that can add tension and interest to a musical composition.
Suspended chords have a distinct sound that sets them apart from major and minor chords. They are called suspended chords because they temporarily suspend the listener’s expectation of hearing a major or minor stable chord. Instead, they feature a perfect fourth or major second interval in place of the third. Due to their “neutral nature,” suspended chords can sometimes be used as substitutes for both major and minor chords.
Building the A#sus4 Chord: Different Approaches
Starting from the A# major Scale
To build a sus4 chord, you can use the major scale as a guide and combine a root note, a perfect 4th interval, and a perfect 5th interval.
A# Major
Keyless notation of A# Major scale.
To create an A#sus4 chord, apply the formula R, 4, 5 in the following manner:
- Begin with the Root note, which is A#.
- Select the 4th interval, which is D#, and add it to the chord.
- Finally, add the 5th interval, which is E# (F).
By following this simple formula, you can create a sus4 chord from any major scale.
by Combining Intervals
One method to create a suspended 4th chord is by combining two specific intervals – a perfect 4th, and a major 2nd.
4 + 2 = sus4 Chords
To illustrate, let’s use the A#sus4 chord as an example. By examining the intervals between the notes, we can see that A#-D# forms a perfect 4th interval, and D#-E# creates a major second interval.
How to Use A#sus4 in a Chord Progression
Suspended chords have a unique quality that sets them apart from major and minor chords. They are considered neither major nor minor, which makes them a great tool for creating tension and suspense in a musical composition before resolving to a stable major or minor chord.
In the following tables, you will find the harmonization of the major and relative natural minor scales for keys that include A# major and A# minor chords in various positions and different harmonic roles.
A# major is a theoretical key with a high number of sharps, which makes it impractical to use. Instead, musicians often prefer to use its enharmonic equivalent, which is Bb major. Bb major has only two flats, making it more manageable and commonly used. This principle applies to other keys with an A# major chord, such as E# major, D# major, as well as all the minor keys (Fx, Cx, and B#). Therefore, it is more practical to refer to the equivalent chord, Bbsus4.
A#sus4 as Substitute of A# Maj Chords
In the key of F Major and Cx minor, the 4th note D# may clash with the D or the E note that is present in those keys. While this doesn’t prevent you from using the A#sus4 chord in those positions, it’s important to be aware that it can create a strong dissonance with the melody or other elements of the composition.
on Major Scales
| Major Scales | I | ii | iii | IV | V | vi | vii |
|---|---|---|---|---|---|---|---|
| A# = Bb | Bb Maj7 ⇒ Bbsus4 = A#sus4 | C min7 | D min7 | Eb Maj7 | F Maj7 | G min7 | Am7b5 |
| E# = F | F Maj7 | G min7 | A min7 | Bb Maj7 ⇒ Bbsus4 = A#sus4 | C Maj7 | D min7 | Em7b5 |
| D# = Eb | Eb Maj7 | F min7 | G min7 | Ab Maj7 | Bb7 ⇒ Bbsus4 = A#sus4 | C min7 | Dm7b5 |
- Tonic chord in Bb Major as Bbsus4
- Non Diatonic Subdominant chord in F Major as Bbsus4
- Dominant chord in Eb Major as Bbsus4
on Natural minor Scales
| Minor Scales | i | ii | III | iv | v | VI | VII |
|---|---|---|---|---|---|---|---|
| Fx = G | G min7 | Am7b5 | Bb Maj7 ⇒ Bbsus4 = A#sus4 | C min7 | D min7 | Eb Maj7 | F7 |
| Cx = D | D min7 | Em7b5 | F Maj7 | G min7 | A min7 | Bb Maj7 ⇒ Bbsus4 = A#sus4 | C7 |
| B# = C | C min7 | Dm7b5 | Eb Maj7 | F min7 | G min7 | Ab Maj7 | Bb7 ⇒ Bbsus4 = A#sus4 |
- Mediant chord in G minor as Bbsus4
- Non Diatonic Submediant chord in D minor as Bbsus4
- Leading tone chord in C minor as Bbsus4
A#sus4 as Substitute of A# min Chords
While the A#sus4 chord can be used as a substitute or variation for A# minor 7th chords, it’s important to note that an A#7sus4 chord would be a better fit due to the presence of the minor 7th.
on Major Scales
| Major Scales | I | ii | iii | IV | V | vi | vii |
|---|---|---|---|---|---|---|---|
| G# = Ab | Ab Maj7 | Bb min7 ⇒ Bbsus4 = A#sus4 | C min7 | Db Maj7 | Eb7 | F min7 | Gm7b5 |
| F# | F# Maj7 | G# min7 | A# min7 ⇒ A#sus4 | B Maj7 | C#7 | D# min7 | E#m7b5 |
| C# | C# Maj7 | D# min7 | E# min7 | F# Maj7 | G#7 | A# min7 ⇒ A#sus4 | B#m7b5 |
- Supertonic chord in Ab Major as Bbsus4
- Mediant chord in F# Major
- Submediant chord in C# Major
on Natural minor Scales
| Minor Scales | i | ii | III | iv | v | VI | VII |
|---|---|---|---|---|---|---|---|
| A# | A# min7 ⇒ A#sus4 | B#m7b5 | C# Maj7 | D# min7 | E# min7 | F# Maj7 | G#7 |
| E# = F | F min7 | Gm7b5 | Ab Maj7 | Bb min7 ⇒ Bbsus4 = A#sus4 | C min7 | Db Maj7 | Eb7 |
| D# | D# min7 | E#m7b5 | F# Maj7 | G# min7 | A# min7 ⇒ A#sus4 | B Maj7 | C#7 |
- Tonic chord in A# minor
- Subdominant chord in F minor as Bbsus4
- Dominant chord in D# minor
A#sus4 in A# Major
Check Bbsus4 in Bb Major
A#sus4 in E# Major (Non Diatonic)
Check Bbsus4 in F Major
A#sus4 in D# Major
Check Bbsus4 in Eb Major
A#sus4 in Fx Minor
Check Bbsus4 in G minor
A#sus4 in Cx Minor (Non Diatonic)
Check Bbsus4 in D minor
A#sus4 in B# Minor
Check Bbsus4 in C minor
A#sus4 in G# Major
Check Bbsus4 in Ab Major
A#sus4 in F# Major Key
In the key of F# Major, the A#sus4 chord can be used on the III degree, adding a different tonal color to the progression.
| I | ii | iii | IV | V | vi | vii |
| F# Maj7 | G# min7 | A# min7 | B Maj7 | C#7 | D# min7 | E#m7b5 |
A#sus4 Chord Progressions as iii degree
I iii IV V
| I | iii | IV | V |
| F# Maj7 | A#sus4 | A#m7 | B Maj7 | C#7 |
I iii ii V
| I | iii | ii | V |
| F# Maj7 | A#sus4 | A#m7 | G# min7 | C#7 |
I iii vi IV
| I | iii | vi | IV |
| F# Maj7 | A#sus4 | A#m7 | D# min7 | B Maj7 |
A#sus4 in C# Major Key
Let’s explore how the A#sus4 chord can function as a submediant chord in the key of C# major. You can try incorporating it into chord progressions that feature an A# minor chord on the VI degree.
| I | ii | iii | IV | V | vi | vii |
| C# Maj7 | D# min7 | E# min7 | F# Maj7 | G#7 | A# min7 | B#m7b5 |
A#sus4 as vi degree – Chord Progressions
I iii vi V
| I | iii | vi | V |
| C# Maj7 | E# min7 | A#sus4 | A#m7 | G#7 |
I vi ii V
| I | vi | ii | V |
| C# Maj7 | A#sus4 | A#m7 | D# min7 | G#7 |
I IV ii V iii vi ii V
| I | IV | ii | V | iii | vi | ii | V |
| C# Maj7 | F# Maj7 | D# min7 | G#7 | E# min7 | A#sus4 | A#m7 | D# min7 | G#7 |
A#sus4 in A# Minor Key
When using the A#sus4 chord in the key of A# minor, it can be a great variation for the traditional A# minor chord. The A#sus4 chord, with its suspended nature, adds a sense of ambiguity and tension. It can be effectively used to create anticipation or build up towards a more stable A# minor chord.
| i | ii | III | iv | v | VI | VII |
| A# min7 | B#m7b5 | C# Maj7 | D# min7 | E# min7 | F# Maj7 | G#7 |
A#sus4 Chord Progressions as i degree
i VI VII
| i | VI | VII |
| A#sus4 | A# min7 | F# Maj7 | G#7 |
Modulation
| isus4 | i | isus2 | i |
| A#sus4
A# (E#, A#, D#) |
A# min
A# (E#, A#, C#) |
A#sus2
A# (E#, A#, C) |
A# min
A# (F, A#, C#) |
Use your left hand to play the A# root note, and your right hand to play the remaining notes of the chord.
i iv VI VII
| i | iv | VI | VII |
| A#sus4 | D# min7 | F# Maj7 | G#7 |
A#sus4 in E# Minor Key
Check Bbsus4 in F minor
A#sus4 in D# Minor Key
In the key of D# minor, the A#sus4 chord can be used on the v (fifth) degree.
| i | ii | III | iv | v | VI | VII |
| D# min7 | E#m7b5 | F# Maj7 | G# min7 | A# min7 | B Maj7 | C#7 |
A#sus4 as v degree – Chord Progressions
i iv VI v
| i | iv | VI | v |
| D# min7 | G# min7 | B Maj7 | A#sus4 | A#m7 |
i v VI VII
| i | v | VI | VII |
| D# min7 | A#sus4 | A#m7 | B Maj7 | C#7 |
i VI v iv
| i | VI | v | iv |
| D# min7 | B Maj7 | A#sus4 | A# min7 | G# min7 |
Alternative Names for A#sus4
- A#sus4
- A#sus(4)
- A# add4(no3)
- A# add4(omit3)
- A# Suspended 4th
Conclusion
While the chord progressions and examples in this post offer a comprehensive overview of common uses for the A#sus4 chord, space constraints prevent a full exploration of advanced harmony topics. These include chord progressions based on scales, modal interchange, and jazz harmony. However, I encourage readers to continue studying and exploring to gain a deeper understanding of the harmonic possibilities beyond the basic concepts presented here. You can unlock a wide range of musical expressions and expand your creativity.
I hope this post has been informative and helpful in your music theory journey. Keep exploring and creating music, and don’t forget to have some fun along the way!