Augmented 6 chords – Summary

We have looked at the three types of augmented 6 chords. Below is a summary of important information about these chords.

In general, augmented 6th chord are altered chords that contain the interval of an augmented 6.

Types of Augmented 6 chords

There are three types of augmented 6th chords: The Italian 6 (It6), the German 6 (Ger6) and the French 6 (Fr6).

All three types of augmented 6 chords contain the interval of an augmented 6. Most commonly, this augmented 6th interval is made up of the notes a half step (minor 2) above the dominant and a half step (minor 2) below the dominant.

In addition to the Augmented 6 interval, the Italian 6 contains the interval of a Major 3 above the bass note.

The German 6 contains intervals of a Major 3, Perfect 5 and Augmented 6 above the bass.

The French 6 contains the intervals of a Major 3, Augmented 4, and Augmented 6 above the bass note.

Resolution of Augmented 6 Chords

One of the main rules of voice-leading is to resolve altered or tendency notes in the direction of their alteration or tendency. Following this rule makes the resolution of augmented 6 chords very easy.

Resolution of Aug 6 interval

First, resolve the augmented 6 interval to an octave by taking the bass note down a half step (in the direction of its alteration) and the top note of the Augmented 6 up a half step (in the direction of its alteration).

Italian 6

The Italian 6, as shown above, has three notes – the bass, a major 3 above the bass, and an augmented 6 above the bass. For 4-part writing one note should be doubled.

The main rule of doubling is to double the stable tone. The only stable, i.e., non-altered/tendency tone, in this chord is the note a 3rd above the bass. Therefore, this note (the D in the above chord) is doubled.

These two notes should resolve to the nearest chord tone – in this case, one to the E and one to the C#.

French 6

To resolve a French 6 chord, first resolve the interval of the augmented 6 as usual.

Next, keep the common tone (the E in the chords below).

Move the other note to the chord tone that is needed. In the example below, move the D to the C#.

German 6

Resolving the German 6 is a bit trickier.

First resolve the augmented 6 interval. Then take the other notes to the nearest chord tone moving in the direction of their alteration. Thus, the F-natural will need to move down to the E.

However, resolving the German 6 directly to a V chord results in parallel 5ths which are impossible to avoid.

(The example below is re-written to better show the parallel 5ths.)

You can either embrace the parallel 5ths or try to avoid them.

To avoid them, the Germ can resolve to a cadential 64 chord before the V as shown below. Doing this makes one note of the 5th interval move before the other, technically avoiding parallels.

Another way to avoid the parallels is to move to another augmented 6th chord before going to the V. In the example below, the German moves to a French 6 before going to the V. Again, this negates the parallel 5ths since both notes of the interval do not move at the same time.