THE AUGMENTED SIXTH CHORD

This page is a supplement to The Complete Musician: Chapter 24 - The Augmented Sixth Chord

The final non-diatonic chord type we will be studying in this term is the AUGMENTED SIXTH CHORD. The chord can be a bit confusing and enigmatic because it uses both a ♯4 (the most common tonicizing non-diatonic tone from the V/V) and a ♭6 (the most common non-diatonic tone from a number of borrowed chords); so it floats somewhere between tonicization and modal mixture. The book even refers to it as a “chameleon” because it can serve both predominant and dominant functions, which makes it uniquely suited for moving from a predominant to dominant area. There are several types/qualities of augmented sixth chords but they all have a few things in common:

ALL AUGMENTED SIXTH CHORDS …

• Serve as “predominant” in that they all have scale degrees ♯4 - ♭6 - 1

• are preceded by predominant or tonic chords

• are immediately followed by a dominant area chord like V, V⁷, or I⁶⁴ (since the ♯4 and ♭6 will both resolve to 5)

• have ♯4 - ♭6 - 1 and one other note

• usually have the ♯4 in the soprano voice (but it may be in the alto or tenor)

• are mostly found in first inversion with the ♭6 in the bass and the root of the chord (♯4) above, making the distance between ♭6 and ♯4 above the interval of an AUGMENTED SIXTH (which is where the chord gets its name)

AUGMENTED SIXTH CHORD TYPES

There are three types of Augmented Sixth Chords depending on what the fourth note is besides the 1, ♯4, and ♭6. Each of the three types are named after a European country. There is absolutely no rhyme or reason as to why each type has the name it does. It’s like how the French horn and English horn are not actually from those countries but someone just decided to call them that. The three types of Augmented Sixth Chords are the Italian, French, and German Augmented Sixths. Before you learn what makes them different, take a look at where the three countries are on this map:

Notice how Italy is the southern-most country and Germany is the northern-most country of the three. Also notice how I have labeled them from south to north: 1 - 2 - ♭3. Memorizing the relationship between the country’s placement and the labeled scale degree will help you out a ton.

ITALIAN AUGMENTED SIXTH CHORD

The Italian Augmented Sixth Chord (It⁺⁶) is an augmented sixth chord that uses ♭6 - 1 - 1 - ♯4. It only has three pitches in it with the root of the key doubled. In C, this chord would be A♭- C - F♯. Notice that if we respell the chord tones enharmonically, this chord could also be: A♭- C - G♭ which are the same chord tones of an A♭⁷ chord without the chordal 5 (E♭) so often, you might see a ♭VI⁷ (without a fifth) which you could also reinterpret as an It⁺⁶.

FRENCH AUGMENTED SIXTH CHORD

The French Augmented Sixth Chord (Fr⁺⁶) is an augmented sixth chord that uses ♭6 - 1 - 2 - ♯4. When this chord resolves to V, the 2 stays in the same voice. It is also referred to as the Fr⁴³ because if you reorder the notes, you will see it’s actually a strange seventh chord starting on scale degree 2 (2 - ♯4 - ♭6 - 1) so to have the ♭6 in the bass implies a second inversion chord off the 2 as the root.

GERMAN AUGMENTED SIXTH CHORD

The German Augmented Sixth Chord (Ger⁺⁶) is an augmented sixth chord that uses ♭6 - 1 - ♭3 - ♯4. German 6ths usually move to a I/i⁶⁴ chord before the V chord which would allow you to keep the ♭3 voice before resolving it down to 2 in V. It is also referred to as the Gr⁶⁵ because the introduction of the ♭3 makes the root position chord a seventh chord starting on ♯4 (♯4 - ♭6 - 1 - ♭3). This is the most common augmented sixth chord.

USING AUGMENTED SIXTH CHORDS

Since both the ♯4 and ♭6 have a pull toward 5, augmented sixth chords will naturally pull to resolve to V. However, this creates a unique problem in that moving straight from a German augmented sixth chord to a V chord will result in parallel fifth movement. It is therefore better to include a Cadential 64 chord between them to avoid parallel fifths: Ger⁺⁶ - I⁶⁴ - V. If moving from the augmented sixth chord to a V⁷, the ♯4 will move downward to the 4 (chordal 7th of V) instead of resolving up a half step to the 5.

Augmented sixth chords also help as an intermediate step between ♭VI and V in both minor and borrowed major keys. Moving from ♭VI - Ger⁺⁶ - V avoids parallel octaves from ♭6 - 5 in the doubled roots.

They can serve as both tonicization and pivot chords in modulation.

You can enharmonically respell a German augmented sixth chord in one key to the V⁷/♭II so it’s a great chord to use as a pivot if you want to modulate your piece up a half step.

AUGMENTED SIXTH CHORDS IN PRACTICE

THE ITALIAN SIXTH

Not going to lie, I only found examples of “true” Italian sixth chords in pre-20th century examples like Beethoven and Schubert and other tunes from the Classical canon already supplied by your textbook. So here is an example of an equivalent chord with a different enharmonic spelling in a bebop lead sheet …

I could make an argument here about not finding any Italian sixth chord past the turn of the 20th century and how maybe it’s not an extremely relevant chord except to study Baroque through Romantic Era music, but there is one interesting adaptation to 20th century harmony here in that an enharmonic respelling of an Italian sixth chord (♭6 - 1 - ♯4) could also become a dominant ♭VI⁷ minus the chordal 5th (♭6 - 1 - no 3 - ♭5) … and actually, this is what you do with most jazz voicings anyway. If we can agree on that fact, then we can agree that any occurrence of a ♭VI⁷ in jazz would carry the same chord tones as an Italian sixth chord … especially if it serves in a predominant function and moves to a dominant chord (like the V) after.

In the example above by JOHN COLTRANE (1927 - 1967), jazz saxophonist and composer, the jazz HEAD (a melody with chord changes meant to be played once then improvised over) “Mr. P.C.” is in the form of a 12-bar minor blues. Usually in this structure, the i in m. 8 would move directly to the V in m. 9, but in this instance, it passes from i through a brief predominant moment in the form of an Italian sixth chord enharmonically spelled as a ♭VI⁷. Also notice that it resolves to a V⁷⁺⁹ and we don’t have time to get into what that chord is doing … just, jazz.

THE FRENCH SIXTH

HARRY THACKER BURLEIGH (1866 - 1949) was an American singer, classical composer, and arranger. In this art song, “Among the Fuchsias” (1915), two French sixth chords are used in the opening verse. The first, occurring at m. 8 is treated as the predominant chord that passes a jazz-influenced i⁷ to V⁷. The second at m. 12 passes the major VI to V⁷ by way of cadential 64 chord. Notice that the use of both French sixth chords are on the rhyming ends of the first and third line of text: “Call me not to a secret place” and “Tempt me not with thine eager face”. The chord sustaining two beats halfway through the phrase serves to add further weight to its harmonic relevance.

THE GERMAN SIXTH

The American “March King” JOHN PHILIP SOUSA (1854 - 1932) penned Semper Fidelis in 1888 while director of “The President’s Own” United States Marine Band. The score above is a piano reduction of the second strain, showing off the use of a German sixth chord as a descending chromatic bass movement from a vi - V (with the addition of a cadential 64). On both repeats through the second strain, the German sixth leaps from the harmonic texture due to the use of non-diatonic tones, the half note length of the chord, the sforzandissimo dynamic marking, and the fact that it lands on the fourth of an eight measure phrase with a sense of interruption.

AUGMENTED SIXTH & NEAPOLITAN CHORD
REVIEW w RICK BEATO …