6.3 Enharmonic Modulation

Enharmonic modulation is a powerful tool for composers to move between distant keys smoothly. By respelling chords like diminished sevenths and augmented sixths, musicians can create unexpected harmonic shifts and exploit remote key relationships.

This technique adds depth to tonal compositions by creating functional ambiguity and allowing for creative transitions. It's a key part of expanding harmonic possibilities beyond closely related keys, giving composers more flexibility in their musical journeys.

Enharmonic Chords

Diminished Seventh and Augmented Sixth Chords

Top images from around the web for Diminished Seventh and Augmented Sixth Chords

• 

  Augmented sixth chord - Wikipedia View original

  Is this image relevant?

• 

  Augmented sixth chord - Wikipedia View original

  Is this image relevant?

• 

  Tonicization – Open Music Theory View original

  Is this image relevant?

• 

  Augmented sixth chord - Wikipedia View original

  Is this image relevant?

• 

  Augmented sixth chord - Wikipedia View original

  Is this image relevant?

1 of 3

Top images from around the web for Diminished Seventh and Augmented Sixth Chords

• 

  Augmented sixth chord - Wikipedia View original

  Is this image relevant?

• 

  Augmented sixth chord - Wikipedia View original

  Is this image relevant?

• 

  Tonicization – Open Music Theory View original

  Is this image relevant?

• 

  Augmented sixth chord - Wikipedia View original

  Is this image relevant?

• 

  Augmented sixth chord - Wikipedia View original

  Is this image relevant?

1 of 3

• Diminished seventh chord contains a diminished triad and a diminished seventh above the root
• Consists of a series of minor thirds stacked on top of each other
• Can be respelled enharmonically as a diminished seventh chord on any of its tones
• Augmented sixth chord includes a major third and an augmented sixth above the bass note
• Three types: Italian sixth, French sixth, and German sixth
• Italian sixth consists of an augmented sixth, major third, and doubled root (Ab-C-F#)
• French sixth adds a perfect fourth to the Italian sixth (Ab-C-D-F#)
• German sixth includes an augmented sixth, perfect fifth, and major third (Ab-Eb-C-F#)

Dominant Seventh Chords and Enharmonic Equivalence

• Dominant seventh chord contains a major triad and a minor seventh above the root
• Can be respelled enharmonically to function as another chord type
• Example: G7 (G-B-D-F) can be respelled as an augmented sixth chord (Ab-C-Eb-F#)
• Enharmonic equivalence occurs when two chords with different spellings sound the same
• Allows for smooth modulations to remote keys
• Example: C7 (C-E-G-Bb) is enharmonically equivalent to Db7 (Db-F-Ab-Cb)

Enharmonic Modulation Techniques

Respelling Chords for Modulation

• Respelling a chord enharmonically can facilitate a modulation to a new key
• Example: Respelling G7 (G-B-D-F) as an augmented sixth chord (Ab-C-Eb-F#) in the key of C minor
• The augmented sixth chord resolves to the dominant chord in the new key (G major)
• Respelling diminished seventh chords can lead to modulations to remote keys
• Example: Respelling Cdim7 (C-Eb-Gb-Bbb) as Bdim7 (B-D-F-Ab) facilitates a modulation from C minor to E minor

Exploiting Remote Key Relationships

• Enharmonic modulations can establish relationships between keys that are not closely related
• Example: Modulating from C major to E major by respelling C7 (C-E-G-Bb) as B#7 (B#-Dx-F#-A)
• The respelled dominant seventh chord resolves to the tonic in the new key (E major)
• Composers can use enharmonic modulations to create unexpected harmonic shifts
• Example: Modulating from A major to Db major by respelling A7 (A-C#-E-G) as Bbb7 (Bbb-Db-Fb-Abb)

Functional Ambiguity in Enharmonic Modulations

• Enharmonic respellings can create functional ambiguity, allowing chords to serve multiple roles
• Example: G7 (G-B-D-F) can function as a dominant seventh in G major or an augmented sixth chord in C minor
• This ambiguity enables smooth transitions between keys
• Composers can exploit functional ambiguity to create harmonic interest and complexity
• Example: Using a German sixth chord (Ab-C-Eb-F#) as a pivot chord to modulate from C minor to G major