Ab7#5 Piano Chord

Piano Diagram of Ab7#5 in Root Position

An Ab7#5 chord is an altered dominant seventh chord that is built upon the key of Ab. This chord consists of the root note Ab, the major third C, the augmented fifth E, and the minor seventh Gb. However, due to the dissonance created by the augmented triad, the Ab7#5 chord can be used as a substitute for dominant chords only in specific musical contexts. Another common use of this chord is as part of a modulation to or from an Ab7 chord. If you keep reading, you will learn more about the music theory that underpins this chord.

 

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Structure of Ab7#5

 

Fingers Position

How to play an Ab7#5

To play an Ab7#5 chord, you can use the following voicing: begin by playing the root note Ab with your left hand. Then, with your right hand, play the notes Gb (minor 7th), C (major 3rd), and E (sharp 5th).

Ab + Gb, C, E

This will result in a voicing of Ab7#5 that includes all notes: the root note, major 3rd, minor 7th, and sharp 5th.

 

Ab7#5 Chord Inversions

 

The Ab7#5 chord has a total of 3 inversions:

 Piano Keyboard Diagrams

Chord Inversions on Piano

A solid grasp of chord inversions is essential in music theory as it provides insights into how chords are built. When playing chord inversions on a piano, it’s crucial to realize that the charts depicting the note order may not always be practical or playable.

To achieve the correct chord voicings on a piano, you need to distribute the chord notes across different octaves and positions on the keyboard. This often involves deviating from the standard shape of the chord’s inversions presented in charts, which may not be the most practical or comfortable way to play the chord.

While chord inversion charts are useful for understanding the structure and sequence of notes in a chord, it’s advisable to experiment with different voicings and fingerings to discover the most efficient and comfortable way to play the chord, while still maintaining its intended harmonic function and sound.

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Music Theory and Harmony of Ab7#5

 

Dominant 7#5 chords are often used as a transitional chord to add an extra layer of tension to a dominant 7th chord and prepare for the resolution to the tonic. The Ab7#5 chord can substitute or enhance the Ab7 chord, commonly on the V degree, but also on the III degree, and occasionally on other degrees as a secondary dominant chord.

Before examining the most common use of this chord, let’s learn how to build it.

 

Building the Ab7#5 Chord: Different Approaches

 

Starting from the Ab Major Scale:

To form an Ab7#5 chord, you combine the root (Ab), the major 3rd (C), the augmented 5th (E), and the minor 7th (Gb) from the Ab scale.

 

 

 

To create an Ab7#5 chord, apply the formula R, 3, #5, m7 in the following manner:

1. Begin with the Root note, Ab.
2. Select the major 3rd interval, which is C.
3. Add the 5th interval, which is Eb then raise it by half step: E.
4. Add the minor 7th interval, Gb.

By following this simple formula, you can create a 7#5 chord from any major scale.

 

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by Combining Intervals:

One method to create a 7#5 chord is by combining specific intervals – a major 3rd, a major 3rd, and a 2nd.

3 + 3 + 2 = 7#5 Chords

For example, to build an Ab7#5 chord:

• we start with the root note Ab.
• We then add a major 3rd interval, which is four half-steps up from the root, to get C.
• Next, we add another major 3rd interval, which is again four half-steps up from C, to get E.
• Finally, we add a 2nd interval, which is two half-steps up from E, to get Gb.

Together, these intervals form the Ab7#5 chord.

 

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How to Use Ab7#5 in a Chord Progression

 

The Ab7#5 can work as a substitute or as a passing chord to an Ab7 that can be found in major and natural minor scales. However, note that it’s a non-diatonic chord due to the presence of the augmented 5th.

These tables show the harmonized major and natural minor scales where you can find an Ab7 or use it in place of other chords.

Most common uses of Ab7#5

Ab7#5 in Db Major and Db minor

The Ab7#5 chord is a popular choice for creating tension in music, often functioning as a dominant chord. In the context of the key of Db major, you can use Ab7#5 as the V7 chord, setting the stage for a resolution back to the I chord (Db major).

• Substitute or Passing Chord to the Dominant chord in Db Major

 

Ab7#5 as Substitute for Ab min7

The Ab7 chord, taken from the harmonic minor scale, is frequently chosen to substitute for an Ab min7 chord in the key of Db minor. In certain situations, you can also opt for the Ab7#5 chord instead of the Ab7 chord, intensifying the harmonic tension and guiding the progression towards the Db min7 chord.

However, since Db minor is a theoretical key, we will refer to its enharmonic equivalent key, C# minor.

• Substitute or Passing Chord to the Dominant chord in C# minor as G#7#5

 

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Ab7#5 in a I – III7 Progression

The Ab7#5 chord could be used as a substitute for the III degree in a I – III7 chord progression. This progression typically involves an Ab minor chord, but when using the chords Fb Maj7 (I) and Ab7 (III7), you can introduce the Ab7#5 chord instead of the usual Ab minor chord.

However, Fb major is another theoretical key so it’s better to refer to its enharmonic equivalent key E major.

• Substitute or Passing Chord to the Mediant chord in E Major as G#7#5

 

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Ab7#5 in Bb minor

Although the Ab7#5 chord can find a place in the key of Bb minor, it might not be as commonly used in this context. In fact, its resolution to Bb minor may not be as strong as its resolution to Db major or Db minor.

• Substitute or Passing Chord to the Leading Tone chord in Bb minor (less common)

 

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Ab7#5 as Substitute for a Secondary Dominant 7th chord

A secondary dominant is a chord that doesn’t belong to the main key of a musical piece but is used to strongly lead to another chord that does. In Western music, the fifth note of the scale has a powerful “dominant” role, creating tension that naturally resolves to the first note of the scale (I). A secondary dominant chord serves the same purpose but directs this dominant function to a different chord, causing a temporary shift away from the main key.

For instance, in the key of Gb major, the Db7 chord serves as the V chord, leading back to the I chord of Gb Maj7. Introducing an additional chord between Gb Maj7 and Db7 that strongly gravitates towards Db7 results in a secondary dominant chord. In this scenario, including an Ab7 chord generates a pull towards Db7, as Ab7 functions as the V chord in the key of Db.

| Gb Maj7 | Db7 |

⇒

| Gb Maj7 | Ab7 | Db7 |

Instead of using a standard Ab7 chord, you can opt for the Ab7#5 chord in its place or in combination with it. This substitution or addition can add more tension and complexity to the progression, leading to a more interesting and dynamic musical result.

| Gb Maj7 | Db7 |

⇒

| Gb Maj7 | Ab7/Ab7#5 | Db7 |

 

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Ab7#5 Chord Function in Major and Minor Keys

 

Ab7#5 as Dominant Chord in Db Major

In the key of Db major, the Ab7 chord would be the dominant chord. The Ab7 chord can be coupled or substituted by an Ab7#5, let’s see how:

 

Ab7#5 Chord Progressions as V degree

Try playing these chord progressions to get an idea of how Ab7#5 functions near the dominant chord. Begin by playing an Ab7 for half a measure, followed by an Ab7#5. This will create an ascending tension that sounds particularly pleasing in the key of Db Major.

ii V I

 

I IV V

 

 I V vi IV

 

I IV vi V

 

 I IV ii V iii vi ii V

 

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Ab7#5 as Dominant Chord in Db minor

Check G#7#5 in C# minor

 

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Ab7#5 as III7 Degree in Fb Major

Check G#7#5 in E Major

 

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Ab7#5 as Leading Tone Chord in Bb minor

In the key of Bb minor, the Ab7 chord is constructed on the leading tone, which is the seventh note of the scale. This chord can be substituted or changed to an Ab7#5, although it might not be the most optimal position for this chord. Nevertheless, it remains a valid choice in specific musical situations.

 

Ab7#5 as VII degree – Chord Progressions

 

i iv VII i

 

i VII VI V

 

i III VII VI

 

i iv VII VI

 

i iv VII III

 

Circle Progression

 

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Alternative Ab7#5 Nomenclature

• Ab 7+5
• Ab 7(#5)
• Ab aug7
• Lab 7#5
• Ab 7#5th
• Ab 7 aug5
• Ab Dominant 7th #5
• Ab Dominant Seventh Sharp Fifth

 

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Conclusion

The chord progressions and examples presented in this post provide a comprehensive overview of the most common uses of the Ab7#5 chord. It’s important to note, however, that many advanced harmony-related topics could not be included due to space constraints. These topics include chord progressions built on harmonic and melodic scales, modal scales, hidden tonality, secondary dominants and other chord substitutions, non-functional harmony and atonal music, modal interchange and borrowed chords, voice leading and counterpoint, chromatisms, jazz harmony…I mean, music theory is a huge topic!

Although I couldn’t cover all of these topics in my post, I encourage readers to continue exploring these areas in their own study and research. By expanding your knowledge in these advanced areas of music theory, you can gain a deeper understanding of the harmonic possibilities that exist beyond the basics presented here.