Ab dim7 Piano Chord

Piano Diagram of Ab dim7 in Root Position

Ab dim7 is a four-note chord that consists of a diminished triad (Ab, Cb, Ebb) with an added diminished 7th Gbb (F). In other words, it’s a stack of minor 3rd intervals on top of the Root note A-flat. Keep reading to learn more about the music theory behind this chord.

Structure of Ab dim7

Notes
Ab, Cb, Ebb, Gbb

Intervals
R, m3, d5, d7

Fingers Position

Left Hand
5, 3, 2, 1 5, 4, 2, 1

Right Hand
1, 2, 3, 4 1, 2, 3, 5

Ab dim7 Chord Inversions

The Ab dim7 chord has a total of 3 inversions:

Root Position:	Ab	Cb	Ebb	Gbb
1st Inversion:	Cb	Ebb	Gbb	Ab
2nd Inversion:	Ebb	Gbb	Ab	Cb
3rd Inversion:	Gbb	Ab	Cb	Ebb

Piano Keyboard Diagrams

: Ab dim7 Chord – Root Position

: Ab dim7 Chord – 1st Inversion

: Ab dim7 Chord – 2nd Inversion

: Ab dim7 Chord – 3rd Inversion

Page Contents

Ab dim7 Inversions Equivalences

Each note that makes up an Ab dim7 chord can also be used as the root to create another diminished seventh chord. For example, if we start with an Ab diminished seventh chord (Ab, Cb, Ebb, Gbb), we can change the starting note to Cb (B), Ebb (D), or Gbb (F) to make a new diminished seventh chord with the same notes, just in a different order. Basically, all three inversions of an Ab dim7 chord can be seen as separate diminished seventh chords. So we have:

Ab dim7 = Cb (B) dim7 = Ebb (D) dim7 = Gbb (F) dim7

The reason each note in an Ab dim7 chord can function as the root to create another diminished seventh chord is that the notes are all evenly spaced apart by intervals of a minor third. They have a symmetrical structure, meaning that each note is separated by the same distance of a minor 3rd interval. This means that when we start on any note in the chord and continue to stack minor thirds on top of it, we will always end up with the same four notes that make up a diminished seventh chord.

Abdim7 Root position = Ab, Cb, Ebb, Gbb

1st Inv. = Cb, Ebb, Gbb, Ab = Bdim7

2nd Inv. = Ebb, Gbb, Ab, Cb = Ddim7

3rd Inv. = Gbb, Ab, Cb, Ebb = Fdim7

If you try to build the diminished 7th chord of all keys, you’ll find that there are only three distinct dim7 chords that occur repeatedly, but with a different root note, covering all the keys.

Distinct dim7 Chords	Notes	Root Position	Enharmonic Inversions
C dim7	C – Eb – Gb – Bbb	C dim7	D#/Eb dim7	F#/Gbdim7	A dim7
D dim7	D – F – Ab – Cb	D dim7	F dim7	G#/Ab dim7	B dim7
E dim7	E – G – Bb – Db	E dim7	G dim7	A#/Bb dim7	C#/Db dim7

As you can see, each of the three distinct chords represents a unique combination of four notes, and those four notes can be rearranged into four different inversions of the chord. By using these three distinct chords and their inversions, all 12 keys can be covered.

The choice of C, D, and E dim7 is just arbitrary, you can try to build all dim7 chords from another series of unique dim7 chords.

Music Theory and Harmony of Ab dim7

The first section explains how to build an Ab dim7 chord from the Ab major scale or by combining minor thirds. The following sections discuss the characteristics and harmonic functions of the diminished seventh chord.

In particular, it covers how diminished 7th chords can be used as substitutes, passing chords, or variations for diminished triads, half-diminished, and dominant chords and how they can create tension and anticipation before resolving to more stable chords.

But first, let’s see how to build an Ab dim7 chord.

Building the Ab dim7 Chord: Different Approaches

Starting from the Ab Major Scale

To build a diminished 7th chord, you need the Root, the minor 3rd, the diminished 5th, and the diminished 7th note. Let’s see how to do it starting from a major scale:

Ab Major Scale

Ab Major Diatonic Scale up to 13th - Keyless Notation

Keyless notation of Ab Major scale.

Start from the root note, Ab.
Lower the major 3rd note by one half-step. In this case, the 3rd note on the Ab major scale is a C. To get a minor 3rd interval, you need to lower it down to a natural B which we call Cb to preserve the basic interval structure of the chord.
Lower the 5th note by one more half-step. Since the 5th note is an Eb, the diminished 5th is an Ebb (D).
Lower the 7th note by two additional half-steps*: the 7th interval on the Ab major scale (G) is a major 7th interval. If you subtract a half step you get a minor 7th interval (Gb). By lowering it down by another half step, you get the diminished 7th interval Gbb (F).
The resulting notes will form a diminished seventh chord with the formula R, m3, d5, and d7*.

*Note: In music theory, intervals like the minor 3rd and minor 7th are one half-step lower than their major counterparts. The diminished 5th interval is also one half-step lower than a perfect 5th, but for naming conventions it’s usually referred to as “diminished” instead of “minor” or “flat”. However, the diminished 7th interval is a little different. This is because the 7th interval can be major, minor, or diminished. To diminish a 7th interval, you need to subtract two half-steps from the major 7th interval, or one half-step from the minor 7th interval.

It’s easy to see that a diminished 7th interval is equivalent to a major 6th. Diminished 7th and major 6th intervals have the same pitch, even though they are named differently.

by Combining 3rds

Alternatively, a diminished 7th chord can be constructed by stacking three minor 3rd intervals on top of each other (a minor 3rd + a minor 3rd + a minor 3rd).

m3 + m3 + m3 = diminished 7th Chords

Let’s see how to build Ab dim7:

Raise the root (Ab) by a minor 3rd interval. This gives you the 3rd note of the chord which is B (Cb). Add another minor 3rd and you get a D (Ebb). Finally, add again another minor 3rd and you’ve completed the chord with the diminished 7th F (Gbb).

Characteristics of Diminished 7th Chords

Diminished 7th chords have a unique sound due to the combination of the first two minor 3rd intervals, creating a tritone interval. This interval spans six half-steps from the root note, and it has a dissonant sound that creates a feeling of instability or harshness.

Because of their dissonant sound, diminished 7th chords require resolution to a more consonant chord. They are commonly used in jazz and classical music genres to create tension and anticipation before resolving to a more stable chord.

How to Use Ab dim7 in a Chord Progression

Diminished 7th chords are highly versatile and can effectively substitute diminished triads, half-diminished, and dominant chords. You can use them as intentional substitutes, passing chords, or variations.

Ab dim7 as a Substitute for dim and m7b5 Chords

Diminished triads are considered “diatonic chords” as they naturally occur in the harmonization of both the natural minor and major scales. In contrast, diminished 7th chords are non-diatonic chords on natural minor and major scales because these scales produce half-diminished chords, which come with a major 7th.

For this reason, you could think that adding a diminished 7th note to a diminished triad may change the effect of the chord, but this is not actually true for diminished 7th chords.

When we look at the inversion of a diminished chord, we can observe a gap between the third and fifth notes in the first inversion, as well as between the fifth and root notes in the second inversion.

: Ab dim Chord – 1st Inversion

: Ab dim Chord – 2nd Inversion

The addition of the diminished 7th note fills in these gaps without fundamentally changing the general feel of the chord. However, it does add a new note that can provide a strong sense of tension or dissonance, making the chord sound more full and rich.

: Ab dim7 Chord – 1st Inversion

: Ab dim7 Chord – 2nd Inversion

The key concept to highlight is that a diminished 7th chord can effectively substitute a diminished triad without significantly altering the chord’s overall impact, despite being a non-diatonic chord for the presence of the diminished 7th interval.

The ratios between the intervals in a diminished 7th chord remain constant, regardless of which note is chosen as the root. Therefore, we can substitute a diminished 7th chord for a diminished triad or a half-diminished chord without altering its essential character.

The tables below show the F# natural minor scale and its corresponding relative major scale, both of which contain a G# dim7 (the enharmonic equivalent of Ab dim7). It’s important to note that when we harmonize diminished triads, they result in a half-diminished chord. Therefore, these tables apply to both diminished triads and half-diminished chords.

The Ab diminished chord can be found on the second scale degree (II) in the Gb natural minor scale and on the seventh scale degree (VII) in the Bbb major scale. However, since these keys are theoretical, we can refer to their enharmonic equivalent keys F# minor and A Major.

on Natural minor Scale

Minor Scale	i	ii	III	iv	v	VI	VII
Gb = F#	F# min	G# dim ⇒ G# dim7 = Ab dim7	A Maj	B min	C# min	D Maj	E Maj

Supertonic chord in F# minor as G# dim7

on Major Scale

Major Scale	I	ii	iii	IV	V	vi	vii
Bbb = A	A Maj	B min	C# min	D Maj	E Maj	F# min	G# dim ⇒ G# dim7 = Ab dim7

Leading tone chord in A Major as G# dim7

as a Substitute for Dominant 7th Chords

Diminished 7th chords can be used as substitutes for dominant 7th chords since they share some of the same notes.

For instance, let’s consider the Ab diminished 7th chord (Ab, Cb, Ebb, Gbb). By lowering certain notes, we can obtain the following chords:

Lowering the root, Ab gives us a G7 chord (G, B, D, F).
Lowering the B note results in a Bb7 chord (Bb, D, F, Ab).
Lowering the D note yields a Db7 chord (Db, F, Ab, Cb).
Similarly, lowering the F note produces an E7 chord (E, G#, B, D).

Given that Ab dim7 is enharmonically equivalent to Cb (B) dim7, Ebb (D) dim7, and Gbb (F) dim7, it can serve as a substitute for any dominant 7th chord with a root a half-step below any of these notes.

Thus, Ab dim7 and its equivalent inversions can replace the following dominant 7th chords in a technique known as #Vdim7 substitution:

G7 (root a half-step below Ab)
Bb7 or A#7 (root a half-step below B)
Db7 or C#7 (root a half-step below D)
E7 (root a half-step below F)

As demonstrated in the table below, only three dim7th chords are needed to substitute for dominant 7th chords in all 12 keys:

Distinct dim7th Chords	Notes	All 12 Dominant 7th Chords
C dim7	C – Eb – Gb – Bbb	B7	D7	F7	Ab/G#7
D dim7	D – F – Ab – Cb	Db/C#7	E7	G7	Bb/A#7
E dim7	E – G – Bb – Db	Eb/D#7	Gb/F#7	A7	C7

Ab dim7 as Supertonic Chord in Gb Minor

Check G# dim7 in F# Minor

Ab dim7 as Leading Tone Chord in Bbb Major

Check G# dim7 in A Major

Ab dim7 as Passing Chord

Here are some tables that demonstrate how Ab dim7 can be used as a passing chord in different keys. When we talk about a passing chord, we mean a chord that is temporarily inserted between two other chords to create a smooth and captivating harmonic progression.

Ab dim7 as Passing Chord in Eb Major

I IV iii ii

I	IV \| IV°⁷	iii	ii
Eb Maj7	Ab Maj7 \| Ab dim7	G min7	F min7

Ab dim7 as Passing Chord in Fb Major

Check G# dim7 in E Major

Ab dim7 as Passing Chord in Ab Major

I ii V

I \| I°⁷		ii	V
Ab Maj7 \| Ab dim7		Bb min7	Eb7

Ab dim7 as Passing Chord in C minor

i vi v iv

i	VI \| VI°⁷	v	iv
C min7	Ab Maj7 \| Ab dim7	G min7	F min7

Ab dim7 as Passing Chord in Db minor

i v iv v

i	v \| v°⁷	iv	v
Db min7	Ab min7 \| Ab dim7	Gb min7	Ab min7

Ab dim7 as Passing Chord in F minor

i III iv V

i	III \| III°⁷	iv	V
F min7	Ab Maj7 \| Ab dim7	Bb min7	C7

Ab dim7 Chromatic Modulations

Ab “dim7 chromatic modulation” refers to a chord progression where a diminished 7th chord is used to create chromatic movement in the harmony. This modulation technique involves incorporating a diminished 7th chord while transitioning from one chord to another, usually by moving in half steps. In the case of Ab dim7, we can find both ascending and descending modulations like these:

Maj or min	Ab dim7 chord	Maj or min
G	Ab dim7	A
or
A	Ab dim7	G

In a chromatic modulation, a diminished 7th chord serves as a pivot chord that connects two different chords. This chromatic modulation can also be applied in various keys where a G chord is followed by an A chord:

Ab dim7 Chromatic Modulation in Abb Major

Check G# dim7 Chromatic Modulation in G Major

Ab dim7 Chromatic Modulation in Ebb

Check G# dim7 Chromatic Modulation in D

i v iv VII in D minor

i	v \| bv°⁷	iv	VII
D min7	A min7 \| Ab dim7	G min7	C7

Ab dim7 Chromatic Modulation in F Major

I iii ii V

I	iii \| biii°⁷	ii	V
F Maj7	A min7 \| Ab dim7	G min7	C7

Ab dim7 as a Substitute for Dominant 7th Chords

Diminished 7th chords can replace dominant 7th chords because they share some of the same notes. However, since all inversions of a dim7 chord are themselves dim7 chords with different names but same notes, any inversion of Ab dim7 can also be used as a substitute for the V degree.

Ab dim7 as a Substitute for G7 in C

In both C major and C minor, you can replace a G7 chord with an Ab dim7. This substitution works because the Ab dim7 chord shares common notes with G7, specifically Cb (B), Ebb (D), and Gbb (F).

Here are some chord progressions in major and minor keys where you can replace a G7 chord with an Ab dim7.

ii #V°⁷ vi in C Major and C minor

ii	V ⇒ #V°⁷	I
D min7	G7 ⇒ G# dim7 = Ab dim7	C Maj7
ii^ø	V ⇒ #V°⁷	i
Dm7b5	G7 ⇒ G# dim7 = Ab dim7	C min7

IV #V°⁷ I in C Major and C minor

IV	#V°⁷	I
F Maj7	G# dim7 = Ab dim7	C Maj7
iv	#V°⁷	i
F min7	G# dim7 = Ab dim7	C min7

I #V°⁷ vi IV in C Major and C minor

I	#V°⁷	vi	IV \| V
C Maj7	G# dim7 = Ab dim7	A min7	F Maj7 \| G7
i	#V°⁷	VI	iv \| v
C min7	G# dim7 = Ab dim7	Ab Maj7	F min7 \| G min7

Ab dim7 as a Substitute for Bb7 in Eb or A#7 in D#

II #V°⁷ I in Eb Major and Eb or D# minor

ii	V ⇒ #V°⁷	I
F min7	Bb7 ⇒ Bdim7 = Abdim7	Eb Maj7
ii^ø	V ⇒ #V°⁷	i
Fm7b5	Bb7 ⇒ Bdim7 = Abdim7	Eb min7
E#m7b5	A#7 ⇒ Bdim7 = Abdim7	D# min7

IV #V°⁷ I in Eb Major and Eb or D# minor

IV	#V°⁷	I
Ab Maj7	Bdim7 = Abdim7	Eb Maj7
iv	#V°⁷	i
Ab min7	Bdim7 = Abdim7	Eb min7
G# min7	Bdim7 = Abdim7	D# min7

I #V°⁷ VI IV in Eb Major and Eb or D# minor

I	V	vi	#V°⁷
Eb Maj7	Bb7	C min7	Bdim7 = Abdim7
i	v	VI	#V°⁷
Eb min7	Bb min7	Cb Maj7	Bdim7 = Abdim7
D# min7	A# min7	B Maj7	Bdim7 = Abdim7

Ab dim7 as a Substitute for Db7 in Gb or C#7 in F#

The Ab dim7 chord acts as an inversion of the #V°7 chord D dim7.

II #V°⁷ I in Gb or F# Major and F# minor

ii	V ⇒ #V°⁷	I
Ab min7	Db7 ⇒ Ddim7 = Abdim7	Gb Maj7
G# min7	C#7 ⇒ Ddim7 = Abdim7	F# Maj7
ii	V ⇒ #V°⁷	i
G#m7b5	C#7 ⇒ Ddim7 = Abdim7	F# min7

I IV #V°⁷ I in Gb or F# Major and F# minor

I	IV	#V°⁷	I
Gb Maj7	Cb Maj7	Ddim7 = Ab dim7	Gb Maj7
F# Maj7	B Maj7	Ddim7 = Ab dim7	F# Maj7
i	iv	#V°⁷	i
F# min7	B min7	Ddim7 = Ab dim7	F# min7

I #V°⁷ VI IV in Gb or F# Major and F# minor

I	#V°⁷	vi	IV \| V
Gb Maj7	Ddim7 = Abdim7	Eb min7	Cb Maj7 \| Db7
F# Maj7	Ddim7 = Abdim7	D# min7	B Maj7 \| C#7
i	#V°⁷	VI	iv \| V
F# min7	Ddim7 = Abdim7	D Maj7	B min7 \| C#7

Ab dim7 as a Substitute for E7 in A

Ab dim7 can function as a substitute for E7 in both A major and A minor. This substitution is possible because Ab dim7 shares common tones with E7, specifically Ab (G#), Cb (B), and Ebb (D).

The tables below showcase chord progressions in major and minor keys where you can replace an E7 with an Ab dim7 chord, which serves as an inversion of the #V°7 chord F dim7.

II #V°⁷ I in A Major and A minor

ii	V ⇒ #V°⁷	I
B min7	E7 ⇒ Fdim7 = Ab dim7	A Maj7
ii	V ⇒ #V°⁷	i
Bm7b5	E7 ⇒ Fdim7 = Ab dim7	A min7

I IV #V°⁷ I in A Major and A minor

I	IV	#V°⁷	I
A Maj7	D Maj7	Fdim7 = Ab dim7	A Maj7
i	iv	#V°⁷	i
A min7	D min7	Fdim7 = Ab dim7	A min7

I #V°⁷ VI IV in A Major and A minor

I	#V°⁷	vi	IV
A Maj7	Fdim7 = Ab dim7	F# min7	D Maj7
i	#V°⁷	VI	iv
A min7	Fdim7 = Ab dim7	F Maj7	D min7

Ab dim as a Substitution for a Secondary Dominant E7

In the key of D major or D minor, the Ab diminished 7th chord (Ab dim7) can serve as a substitution for the secondary dominant E7.

Secondary dominants are chords in traditional harmony that temporarily establish a new tonal center within a piece of music. They typically function as dominant chords of a key other than the tonic. In the key of D major, the secondary dominant E7 would normally resolve to A major. In this particular case, it resolves on an A7, which is the fifth degree of D, and then resolves further to the tonic.

However, Ab dim7 can be used as a substitute for E7 in this context. The Ab dim7 chord creates tension and can resolve effectively to A7, similar to how the E7 chord would resolve.

bV°⁷ V I in D Major and D minor

V⁷/V ⇒ bV°⁷	V	I
E7 ⇒ Ab dim7	A7	D Maj7 or D min7

Alternative Names for Ab dim7

Ab diminished 7th
Abdim7
Ab°7

Conclusion

The chord progressions and examples presented in this post provide a comprehensive overview of the most common uses of the Ab dim7 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 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.