A# aug Piano Chord

Piano Diagram of A# aug in Root Position

An A# augmented chord is an augmented triad built upon the key of A-sharp. To get an A# augmented chord, you combine the root (A#), the major 3rd C_x (“C double sharp”, equivalent to a natural D), and the sharp 5th note E_x (which is equivalent to an F#) from the A-sharp scale. Keep reading to get a better grip on the music theory behind this chord.

 

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A# aug Chord Inversions

 

A# aug has a total of 2 inversions:

Piano Keyboard Diagrams

Inversions Equivalencies

One interesting feature of augmented chords is that each inversion of the chord produces a different augmented chord. For example, if you take the first inversion of an A# augmented chord, you get a D augmented chord (C_x is equivalent to D). And if you take the second inversion of an A# augmented chord, you get an F# (E_x) augmented chord.

So, you only really need four different augmented chords to cover all the possible keys, because all the other augmented chords can be found by inverting these four chords.

 

 

Notice how each of the four distinct augmented chords contains a unique combination of three notes, which can be rearranged into three different chord inversions. By utilizing these four chords and their inversions, it’s possible to cover all 12 keys.

Keep in mind that the selection of C, C#, D, and D# is arbitrary, as you could use any other series of unique augmented chords to build them all.

 

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Music Theory and Harmony of A# aug

 

Augmented chords are typically found on the third degree of both the melodic and harmonic minor scales, where they are intended to function as mediant chords.

F_x Melodic Minor Scale

F_x Harmonic Minor Scale

 

However, in practice, they are not commonly used in this way. Instead, augmented chords are often used as a leading tone to resolve to a major or minor tonic chord.

But before we explore the chords that can follow an A# augmented chord, let’s take a closer look at how to build it.

 

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Building the A# aug Chord: Different Approaches

 

Starting from the A# Major Scale

Keeping as reference the major scale, build the augmented chord, which consists of the Root, major 3rd, and sharp 5th. Keep in mind that A# major is a theoretical key since it has many sharp in its key signature, so it could be easier using its enharmonic equivalent chord Bb aug.

 

 

 

• Start from the root note A#.
• Add the major 3rd C_x (D).
• Raise the 5th note, E# (F) by one half-step to get E_x (which is equivalent to F#.)
• Combine the root note A#, the major 3rd C_x and the augmented 5th E_x to form the A# augmented chord.

You can apply the formula R, 3, #5 to build any augmented chord.

 

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by Combining 3rds

An augmented triad is a chord consisting of two stacked major 3rds.

3 + 3 = aug Chords

To build an augmented triad on A#, you would start from the root note A#. Next, you would add a major third interval above A# to obtain the note D. In this context, we would call this note C_x (C double sharp) to preserve the chord’s basic structure. Finally, you would add another major third interval above D (C_x) to get the note F#. Once again, we would refer to this note as E_x for consistency.

The resulting A# augmented triad would consist of the notes A#, C_x, and E_x.

 

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How to Use A# aug in a Chord Progression

 

Augmented chords can be used in different ways. One of the most common ways they’re used is through substitution, which means they can take the place of other chords.

For example, augmented chords can be used as a substitute for dominant 7th chords. Additionally, they can also work as passing or transitional chords between other chords.

Most of the time, an augmented triad functions as a variation of the dominant chord that resolves on a tonic chord five degrees under its root. However, it is worth mentioning all easy transitions possible starting from an A# aug. The harmonic structure of augmented chords makes it possible to get many different chords just by shifting any of its notes by a half step, let’s see why:

 

Resolving A# aug to Major and minor Chords

An augmented chord is made up of notes that are separated by a specific and constant distance from one another. In the case of an A# augmented chord, the notes A#, C_x, and E_x are separated by a “major 3rd” interval.

It’s important to note that each note in the A# augmented chord can act as a leading tone to transition to another chord that sounds good in the progression. This is because changing one of the notes in the augmented chord can create a different type of chord altogether.

To form a major chord, you need to combine a “major 3rd” interval with a “minor 3rd” interval. Conversely, a minor chord is formed by using a “minor 3rd” interval followed by a “major 3rd” interval. Therefore, when you play an augmented chord, you can use each note in the chord to lead to a different type of chord, such as a major or minor chord, by changing the distance between the notes.

 

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Lowering One Note: from A# aug to Major Chords

The table below shows how lowering each note of the A# aug chord can lead to three different major chords:

 

 

If you lower one note in the A-sharp augmented chord, you will end up creating a major chord from each of its notes. So A# aug can transform into:

• A# (Bb) Major or
• C_x (D) Major or
• E_x (F#) Major

 

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Lowering Two Notes: from A# aug to minor Chords

Lowering two notes of an aug chord results in three minor chords. Let’s explore which minor chords can be derived from the A# aug:

 

 

Lowering two notes of an augmented chord creates three minor chords with the same root as the inversions of the augmented chord. This means that A# aug can transform into:

• A# (Bb) minor or
• C_x (D) minor or
• E_x (F#) minor

This can be useful in minor keys where the v degree is played as a V7 chord (borrowed from the harmonic minor scale). In this case, the A-sharp augmented chord can replace A#7, D7, and F#7 in minor keys.

However, the best fit for A# augmented is to substitute A#7. When it’s played in place of D7 or F#7, it’s actually an inversion of the better fit, D augmented and F# augmented, respectively.

 

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Raising One Note: from A# aug to minor Chords

When you raise one note of an A# aug chord, you get minor chords. The following table shows the three different minor chords that can be created from an A# aug chord:

 

 

When we raise one note of an A-sharp augmented chord, we get:

• B (Cb) minor or
• D# (Eb) minor or
• F_x (G) minor

 

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Raising Two Notes: from A# aug to Major Chords

Similarly, raising two notes of the A# aug chord results in three major chords. Let’s take a look at which chords can be formed:

 

 

When we raise two notes of the A# augmented chord, we can resolve it to three different chords:

• B (Cb) Major or
• D# (Eb) Major or
• F_x (G) Major

 

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A# aug as Dominant Chord

Due to the complexity of theoretical keys, I strongly recommend referring to the enharmonic equivalent chord Bb augmented instead of A# augmented. The tables have become a bit complicated and should be used mainly just for reference. For a clearer understanding of the concepts, it’s better to check the simpler tables related to the more common keys.

As we have seen, A# aug can be transformed into various minor and major chords simply by raising or lowering one or two notes. These tables show all the possible resolutions of the A# augmented chord in major and minor keys, where it can be substituted for the V chord in a ii-V-I/i progression.

Try these progressions and experiment with playing both the augmented and the dominant chords, or just the augmented chord. You can also try playing the dominant chord first, followed by the augmented chord, or vice versa.

 

*Since all these are theoretical keys, we will refer to their enharmonic equivalent keys Eb, G, B, and A major.

• When an A# augmented chord resolves to a D# major, it is functioning as the V+ (augmented fifth) degree in the theoretical key of D# major. This is the most common use of the A# augmented chord as a substitute for the A#7 chord, which creates a strong sense of tension and resolution in the context of a D# major key.
• In the keys of F_x major, A# augmented can replace the V+ chord, which is C_x augmented. This is possible because A# augmented is an inversion of C_x augmented that substitutes the C_x7 chord.
• Similarly, E_x (F#) augmented, which is also an inversion of A# augmented, can be substituted, but it’s usually better to use the augmented chord with the same root of the dominant chord instead of using an inversion.
• The tritone substitution: By replacing a dominant 7th chord with another chord whose root is a tritone away, we can create a new harmonic color while maintaining the original function of the dominant chord. In the case of A# augmented it can be used as a tritone substitution for D_x7 because the distance between A# and D_x is a tritone (six half steps).

 

*Since the A_x minor key is a theoretical key, it’s more practical to refer to its enharmonic equivalent key B minor.

The A# augmented chord can serve as a substitute for the dominant 7th chord in minor keys. It is a common practice to use a dominant 7th chord instead of the minor dominant chord typically found in natural minor keys. This substitution is derived from the harmonic minor scale and is widely used in natural minor key progressions.

Since the A# augmented chord shares the same notes as C_x augmented (D aug) and E_x augmented (F# aug), and because augmented chords can substitute for the dominant 7th chords built on their roots, it follows that A# augmented, being an inversion of both C_x augmented and E_x augmented, can be used to replace C_x7 (D7) and E_x7 (F#7) in their respective keys. However, it’s better to play the augmented chord with the same root as the dominant chord rather than playing an inversion.

 

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A# aug Voice Leading

A# augmented can serve as a chromatic passing chord, allowing for smooth voice leading. It can also function as a pivot chord to modulate to a new key or be used as a substitute for the dominant chord to create a sense of tension and eventual resolution.

 

I I⁺ IV

 

I I⁺ iv

 

I I⁺ VI

 

I I⁺ ii V

 

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A# aug as Chromatic Modulation

Using the A# aug chord for chromatic modulation can add an interesting tonal color to your music. It is a popular technique used to add interest to a series of static measures on a single chord.

I  I⁺ I⁶ I⁺ I

 

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Alternative Names for A# aug

• A#+
• A#+5
• A#aug
• A#(#5)
• A#(5#)
• A#(5+)
• A#aug5
• A#(+#5)
• A#(#5+)
• A#(5aug)

 

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