The French augmented sixth chord is a chromatic harmonic device used across nineteenth- and twentieth-century repertoire to intensify modulation and heighten expressive tension. By reframing the leading tone through an augmented sixth interval, this chord creates a carefully prepared disturbance that resolves in a surprisingly direct way.
Composers exploit its ambiguous, floating quality to blur key areas before landing in a new tonic. Understanding the chord’s structure, common types, and voice-leading habits is essential for interpreters, analysts, and composers working in the common practice and post-Romantic styles.
| Chord Type | Bass Note | Upper Structure | Typical Resolution |
|---|---|---|---|
| Italian ⁺⁶ | ⁺⁶ above tonic | 1 sharp second scale degree | Move to tonic or dominant |
| French ⁺⁶ | ⁺⁶ above tonic | 1 2 3 1 sharp fourth | Expand to tonic or mix |
| German ⁺⁶ | ⁺⁶ above tonic | 1 sharp second 1 sharp fourth | Move to tonic or dominant |
| Altered Variant | Context-dependent | Modified fifth or added tones | Guided toward tonicization |
Harmonic Function and Voice Leading
Augmented Sixth Interval
The augmented sixth interval spans ten semitones, forming the spine of this chord. It typically involves a raised second scale degree paired with the lowered sixth of the destination key. This interval pulls strongly toward the tonic and primes listeners for modulation.
Resolution Patterns
In voice-leading, each component of the French augmented sixth moves in a highly organized fashion. The bass ascends by semitone or whole tone, the sixth expands upward, and the third may stay, step, or leap depending on context. These tendencies create a smooth yet dramatic shift into the new tonic area.
Historical Usage and Repertoire
Composers such as Chopin, Liszt, and Wagner cultivated the French augmented sixth as a vehicle for distant key changes. Their scores demonstrate extended preparatory dominant motions that point toward unexpected mediant, submediant, or lower-third regions. Recognizing these gestures helps listeners hear broader structural designs.
Romantic harmony relies on the chord’s ability to postpone cadence while enriching linear motion. Later impressionist and early modern composers further blurred its function, treating it as a colorful sonority rather than a strictly directional force.
Identification Strategies
Bass and Pitch Set
To identify the chord quickly, listen for a prominent augmented sixth above the bass. If the soprano contains the raised second and the tenor outlines a sharpened subdominant, the French variant is probable. Mapping these intervals against the target key clarifies its role.
Contextual Clues
Harmonic rhythm, phrase length, and orchestration all signal whether the chord is passing, prolongational, or cadential. In dense textures, inner voice motion becomes especially revealing for distinguishing the French type from its German and Italian relatives.
Practical Application and Analysis
Performers and analysts can benefit from mapping voice-leading in score, tracing individual tendencies through measures. Slow practice that highlights each unresolved tendency tone improves intonation and expressive timing. Analytical sketches help clarify how each resolution supports the larger tonal plan.
Key Takeaways for Performers and Analysts
- Recognize the characteristic augmented sixth interval and raised second scale degree.
- Trace inner-voice motion to anticipate modulation targets.
- Practice slow voice-leading drills to secure accurate intonation and timing.
- Compare French, Italian, and German types to sharpen analytical hearing.
- Use expressive timing and dynamic shaping to highlight harmonic tension and release.
FAQ
Reader questions
How does the French augmented sixth differ from the Italian and German types?
The French augmented sixth includes the second scale degree in the chord along with the sharpened subdominant, while the Italian omits the third and the German adds a chromatic third, giving each distinct sonority and typical resolution patterns.
Can this chord appear in minor keys as well as major keys?
Yes, composers use the French augmented sixth in both minor and major contexts, often approaching it via modal mixture or altered dominants to intensify the modulation toward a distant area.
What cadential scenarios suit the French augmented sixth best?
It works well in deceptive resolutions, modulation points, and expansive post-dominant passages where delayed closure enhances dramatic narrative and harmonic surprise.
Are there common pitfalls when voicing this chord in four-part writing?
Avoid parallel fifths and octaves by carefully planning inner voices, and prevent muddy textures by spacing the augmented sixth clearly and resolving tendency tones with precise direction.