Augmented Sixth Chords
The three chromatic pre-dominant chords that defined Romantic classical drama. Italian (It+6), French (Fr+6), and German (Ger+6), each built on the flattened 6th and resolving outward to the dominant.
What Is an Augmented Sixth Chord?
An augmented sixth chord is a chromatic pre-dominant chord that contains an augmented sixth interval. This interval is built between the flattened 6th scale degree (b6) in the bass and the raised 4th (sharped 4, or #4) above it. The two notes are 10 half steps apart, forming the augmented sixth.
The Three Types of Augmented Sixth Chords
All three types share the augmented sixth interval (b6 and #4). They differ in which additional notes they include. All examples below are in C major or C minor.
Italian Augmented Sixth
The simplest form. Only three notes: the b6, the tonic (1), and the #4. The tonic doubles in four-voice writing.
French Augmented Sixth
Adds the 2nd scale degree. The most dissonant of the three types, with the major second between the 1 and 2 creating added tension.
German Augmented Sixth
Adds the b3 (flattened 3rd). Enharmonically identical to a dominant 7th chord, making it the most dramatic and cinematic of the three. The Ger+6 in C sounds exactly like Ab7 but resolves to G major.
Augmented Sixth Chords in All 12 Keys
The augmented sixth is always built on the b6 of the key. Below are all three types for each major and minor key.
| Key | b6 (bass) | It+6 | Fr+6 | Ger+6 |
|---|---|---|---|---|
| C | Ab | Ab-C-F# | Ab-C-D-F# | Ab-C-Eb-F# |
| G | Eb | Eb-G-C# | Eb-G-A-C# | Eb-G-Bb-C# |
| D | Bb | Bb-D-G# | Bb-D-E-G# | Bb-D-F-G# |
| A | F | F-A-D# | F-A-B-D# | F-A-C-D# |
| E | C | C-E-A# | C-E-F#-A# | C-E-G-A# |
| B | G | G-B-E# | G-B-C#-E# | G-B-D-E# |
| F# | D | D-F#-B# | D-F#-G#-B# | D-F#-A-B# |
| F | Db | Db-F-B | Db-F-G-B | Db-F-Ab-B |
| Bb | Gb | Gb-Bb-E | Gb-Bb-C-E | Gb-Bb-Db-E |
| Eb | Cb | Cb-Eb-A | Cb-Eb-F-A | Cb-Eb-Gb-A |
| Ab | Fb | Fb-Ab-D | Fb-Ab-Bb-D | Fb-Ab-Cb-D |
| Db | Bbb | Bbb-Db-G | Bbb-Db-Eb-G | Bbb-Db-Fb-G |
How Augmented Sixth Chords Resolve
The defining characteristic is outward resolution. Both notes of the augmented sixth interval move by half step in opposite directions, both arriving at the dominant (5th scale degree). In C major:
Famous Examples
Beethoven, Piano Sonata Op. 57 "Appassionata"
Ger+6First movement development section. The German augmented sixth drives one of the most dramatic moments in classical piano literature.
Schubert, "Der Erlkonig"
Ger+6Schubert uses the German augmented sixth throughout to create supernatural dread. The enharmonic ambiguity between Ger+6 and a dominant 7th creates tonal instability.
Mozart, Symphony No. 40 in G minor
It+6Italian augmented sixth in the development section. Mozart uses the simpler Italian form to propel motion back to the dominant.
Chopin, Nocturne Op. 9 No. 1
Fr+6Chopin uses the French augmented sixth for its extra dissonance. The Bb minor nocturne features augmented sixth chords at key moments of harmonic intensification.
Radiohead, "Exit Music (For a Film)"
Ger+6The chromatic harmony in this track includes moments that function like German augmented sixths, contributing to the unstable, dark atmosphere.
Film Scores (Hans Zimmer, John Williams)
Ger+6The German augmented sixth is a standard tool in cinematic orchestration. The enharmonic Ab7 sound creates urgency before a tonic resolution, common in action and horror scores.
5 Augmented Sixth Progressions
Classical Cadence
Formal, conclusive, dramatic resolution
The Italian augmented sixth provides a single chromatic pre-dominant before the dominant. Clean and unambiguous.
German Pre-Cadence
Sweeping, Romantic, cinematic
The German augmented sixth resolves via the cadential 6/4 to avoid parallel fifths. This is the standard German augmented sixth resolution in classical writing.
French in Minor
Impressionistic, tense, sophisticated
The French augmented sixth follows the subdominant, intensifying the pre-dominant area before resolving to the dominant 7th.
Ger+6 as Tritone Sub
Jazz reharmonization, smooth and surprising
Exploiting the enharmonic equivalence: Ger+6 in C = Ab7 = the tritone substitute for G7. The bass walks down by half step (D - Ab - C), creating smooth chromatic motion.
Baroque Sequence
Baroque, ornate, elegant surprise
The Italian augmented sixth appears after the submediant (vi), providing chromatic color before the cadential dominant. Works in both major and minor.
Augmented Sixth by Genre
| Genre | Preferred Type | How It Is Used | Subtlety |
|---|---|---|---|
| Classical / Baroque | It+6 | Pre-cadential tension before V in cadences | Medium |
| Romantic / Orchestral | Ger+6 | Climactic moments, deceptive resolutions, tonal ambiguity | High drama |
| Impressionism | Fr+6 | Coloristic harmony, unresolved tension, floating quality | Medium-high |
| Film Score | Ger+6 | Urgency and tension before hero themes, horror stings | High drama |
| Jazz | Ger+6 = tritone sub | Reharmonization, bass line movement, bebop vocabulary | Subtle |
| Neo-Soul / R&B | Fr+6 or Ger+6 | Extended harmony, voice leading into maj7 chords | Subtle |
| Metal / Progressive | Ger+6 | Dark tonal color, pre-riff tension, dissonant pedal builds | Medium |
Augmented Sixth vs Related Chromatic Chords
| Chord | In C | Function | Resolves to |
|---|---|---|---|
| Italian +6 (It+6) | Ab-C-F# | Pre-dominant, 3 notes | V (G major) |
| French +6 (Fr+6) | Ab-C-D-F# | Pre-dominant, most dissonant | V (G major) |
| German +6 (Ger+6) | Ab-C-Eb-F# | Pre-dominant, most dramatic | V6/4 then V |
| Neapolitan (bII) | Db-F-Ab | Pre-dominant, b2 root | V or i |
| Tritone Sub | Ab-C-Eb-Gb | Substitute dominant | I (tonic) |
| Secondary Dominant | V/V = D7 in C | Tonicizing dominant | V (G major) |
| Borrowed bVII | Bb major in C | Modal color | I or IV |
6 DAW Production Tips
Detect the Key First
Use BeatKey to detect the key of your sample or project. Then find the b6 for the augmented sixth: 8 half steps above the tonic.
Voice Ab in the Bass
Always put the b6 (e.g., Ab in C) in the bass. The augmented sixth interval requires the outer voices to resolve outward. Bass voice leading drives the effect.
Use Ger+6 as a Tritone Sub
The German augmented sixth is enharmonically identical to the tritone substitute dominant 7th (Ab7 in C). Swap it into any ii-V-I for a classical chromatic flavor.
Resolve to V, Not I
The augmented sixth chord is pre-dominant. It resolves to V (or V6/4), not directly to I. The two-step motion (+6 to V to I) is what creates the full cadential effect.
Piano Roll Spelling Matters
Use F# (not Gb) above Ab in your DAW. The augmented sixth interval is spelled as an augmented 6th, not a minor 7th. Some MIDI instruments care; notation software always cares.
Use Fr+6 for Neo-Soul Extensions
The French augmented sixth (Ab-C-D-F# in C) works as an extended color chord in neo-soul. The D creates a major 9th texture while the F# provides an unexpected sharp 4 color.
Detect Chords in Your Samples
Identify whether your samples contain augmented sixth chords or other chromatic harmony. Upload audio and get the full chord progression instantly.
Related Chord Theory
Complete BeatKey Tools Suite
Frequently Asked Questions
What is an augmented sixth chord?
An augmented sixth chord is a chromatic pre-dominant chord built on the flattened 6th scale degree. It contains an augmented sixth interval between the b6 (bass) and the #4 (upper voice). In C major or C minor, that interval is Ab to F#. All three types (Italian, French, German) share this interval and resolve outward by half step to the dominant (V) chord.
What is the difference between Italian, French, and German augmented sixth chords?
All three types share the augmented sixth interval (b6 and #4). Italian (It+6) has 3 notes: b6, 1, #4. French (Fr+6) adds the 2nd scale degree: b6, 1, 2, #4. German (Ger+6) adds the b3: b6, 1, b3, #4. The German version is enharmonically identical to a dominant 7th chord on the b6 (Ab7 in C), making it the most harmonically ambiguous and dramatic of the three.
How do augmented sixth chords resolve?
Augmented sixth chords resolve outward by half step to the dominant (V). The b6 (Ab in C) moves down to the 5th (G). The #4 (F# in C) moves up to the 5th (G). Both voices converge on the same pitch from opposite directions. This convergent outward resolution is what defines the augmented sixth chord and why it creates such intense forward motion. The German augmented sixth often resolves via the cadential 6/4 to avoid parallel fifths.
How do you use augmented sixth chords in a DAW?
Use BeatKey to detect the key of your sample. Then build the augmented sixth: in C, use Ab in the bass, add C (tonic) and F# (raised 4th). For Italian, that is Ab-C-F#. For German, add Eb to get Ab-C-Eb-F#. Place the chord before your V (G major or G7 in C). The German augmented sixth also works as a tritone substitute for G7 in jazz reharmonization, exploiting its enharmonic equivalence to Ab7.