A7b5 Piano Chord

Piano Diagram of A7b5 in Root Position

A7b5 is a dominant seventh chord with a flat 5th built on the A major scale. This chord consists of the root note A, the major third C#, the diminished fifth Eb, and the minor seventh G. The flat fifth creates a distinct dissonance so it can be used as a substitute for dominant chords only in specific musical contexts. If you keep reading, you will learn more about the music theory that underpins this chord.

 

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Structure of A7b5

 

Fingers Position

 

How to play an A7b5

Play the root note A with your left hand. Then, with your right hand, play the notes G (minor 7th), C# (major 3rd), and Eb (diminished 5th).

A + G, C#, Eb

Omitting the root on your right hand, you can play also one of the three inversions of the chord.

 

A7b5 Chord Inversions

 

The A7b5 chord has a total of 3 inversions:

 Piano Keyboard Diagrams

 

A7b5 Chord Equivalencies

If you take a 7b5 chord, you can find another 7b5 chord that has the same notes in it by either going up three steps from the root note or going down three steps from the root note.

For example, A is the root note of A7b5 (A, C#, Eb, G), so if you go up three steps from A, you get to D#. Therefore, D#7b5 (D#, F_x, A, C#) has the same notes as A7b5 (F_x is “F double sharp” and is the enharmonic equivalent of G).
Similarly, if you go down three steps from A, you get to Eb (Eb, G, Bbb, Db), so Eb7b5 also has the same notes as A7b5.

A7b5 = D#7b5 = Eb7b5

The reason why going up three steps or going down three steps leads you to a chord with the same notes is because the interval between the root note and the diminished fifth is called a tritone. This interval is halfway between the octave and divides it into two equal parts. Therefore, going up three steps or going down three steps takes you to the same note that is a tritone away from the starting note.

So, the A7b5 chord is equivalent to both D#7b5 and Eb7b5 because they all have the same notes in them, even though they have different names.

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Music Theory and Harmony of A7b5

 

Dominant 7b5 chords are often used as transitional chords to add an extra layer of tension to a dominant 7th chord and prepare for the resolution to the tonic. The A7b5 chord can substitute or enhance the A7 chord, commonly on the V degree in a minor key, 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 A7b5 Chord: Different Approaches

 

Starting from the A Major Scale:

To form a 7b5 chord, you combine the root, the major 3rd, the diminished 5th, and the minor 7th from a major scale. To build an A7b5, you can start with the A Major scale, which consists of A, B, C#, D, E, F#, and G#.

 

 

 

To create an A7b5 chord, apply the formula R, 3, d5, m7 in the following manner:

1. Begin with the Root note, A.
2. Select the major 3rd interval, which is C#.
3. Add the 5th interval, which is E then lower it by half step to get the diminished 5th, Eb.
4. Add the minor 7th interval, G.

By following this simple formula, you can create a 7b5 chord from any major scale.

 

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by Combining Intervals:

One method to create a 7b5 chord is by combining specific intervals – a major 3rd, a major 2nd, and a major 3rd.

3 + 2 + 3 = 7b5 Chords

For example, to build an A7b5 chord:

• we start with the root note A.
• We then add a major 3rd interval, which is four half-steps up from the root, to get C#.
• Next, we add a major 2nd interval, which is two half-steps (a whole tone) up from C#, to get Eb.
• Finally, we add a major 3rd interval, which is four half-steps up from Eb, to get G.

Together, these intervals form the A7b5 chord.

 

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How to Use A7b5 in a Chord Progression

 

The A7b5 can work as a substitute or as a passing chord to an A7 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 diminished 5th.

These tables show the harmonized major and natural minor scales where you can find an A7 or use it in place of other chords.

 

Most common uses of A7b5

 

A7b5 in D Major and D minor

The A7b5 chord is commonly used as a dominant chord. In the key of D major, the A7b5 chord can be used as the V7 chord, which leads back to the I chord (D major).

• Substitute or Passing Chord to the Dominant chord in D Major.

 

A7b5 as Substitute for Am7

The A7 chord derived from the harmonic minor scale is commonly used to replace an Am7 chord in the key of D minor. In some cases, the A7b5 chord can also be used instead of the A7 chord.

• Substitute or Passing Chord to the Dominant chord in D minor.

 

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A7b5 in a I – III⁷ Progression

The A7b5 chord can serve as a substitute for the III chord in a I-III⁷ chord progression that typically features an A minor chord. In the chord progression represented by the chords F Maj7 and A7, the A7b5 chord can replace the expected A minor chord.

• Substitute or Passing Chord to the Mediant chord in F Major.

 

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A7b5 in B minor

The A7b5 chord in the B minor scale could function as a leading tone chord, resolving to the B minor chord.

• Substitute or Passing Chord to the Leading Tone chord in B minor.

 

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A7b5 as Substitute for a Secondary Dominant 7th chord

A secondary dominant is a chord that doesn’t belong to the main key of a song. Instead, it’s used to create a strong pull or tension toward a different chord that does belong to the main key. In Western music, the fifth note of the scale is known for its dominant function, creating tension that typically resolves to the first note of the scale. A secondary dominant serves a similar purpose but directs that tension towards a different chord, briefly taking the music away from the main key.

In the key of G major, the D7 chord serves as the V chord, naturally leading back to G Maj7. If you insert an extra chord between G Maj7 and D7, and this new chord strongly leads toward D7, it transforms into a secondary dominant chord. For example, introducing an A7 chord in this progression creates that pull toward D7, as A7 is the V chord in the key of D.

| G Maj7 | D7 | G Maj7 |

⇒

| G Maj7 | A7 | D7 | G Maj7 |

To spice up a harmonic progression, you can switch out or combine the standard A7 chord with the A7b5 chord. This alteration or inclusion can bring in more tension and complexity to the progression.

| G Maj7 | D7 | G Maj7 |

⇒

| G Maj7 | A7/A7b5 | D7 | G Maj7 |

 

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A7b5 Chord in Major and minor Keys

 

A7b5 as Dominant Chord in D Major

In the key of D major, the A7 chord serves as the dominant chord. However, you can opt to use the A7b5 chord instead of or in combination with the A7 chord. Here’s how you can approach it:

 

A7b5 Chord Progressions as V degree

To get a better understanding of how A7b5 works alongside the dominant chord, try playing these chord progressions. Start by playing an A7b5 chord for half a measure, followed by an A7 chord. This descending tension creates a pleasing sound, especially in the context of the D Major key.

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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A7b5 as Dominant Chord in D minor

A7 can be found also on the V degree of the D harmonic and melodic minor scales. It’s very common to use this chord in combination with chords built on the natural minor scale or to substitute it for the Am7 chord that is present in the natural minor scale. In some contexts, we could use an A7b5 instead of an A7 in this position.

A7b5 as V degree on minor Scale – Chord Progressions

Try playing these chord progressions to get an idea of how A7b5 functions as the subdominant (V degree) in the key of D minor. I recommend playing an A7 chord within the same measure as the A7b5 chord, as it adds a sense of harmonic movement to the progression.

 

ii V⁷ i

 

i iv V⁷

 

i iv VI V⁷

 

i VI V⁷ iv

 

Circle Progression

 

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A7b5 as III⁷ Degree in F Major

This is a very common substitution of dominant chords in place of minor chords. In the case of A7, we are in F major since the minor chord we are going to substitute is on the iii degree of the scale:

 

A7b5 as III7 degree – Chord Progressions

Try playing these chord progressions to get an idea of how A7b5 functions in this position. To understand why this substitution is possible, I suggest checking out some of the posts related to dominant 7th chords. There are different interpretations of this substitution, so it can be helpful to explore them to fully understand its potential use.

 

I III⁷ vi

 

I III⁷ VI⁷ ii

 

I III⁷ IV VI⁷ ii V iii/biii^ø ii/V

 

“All of me” Progression