V. Chromaticism
Chromatic Modulation
Bryn Hughes
Key Takeaways
- Mode mixture offers an easy way to modulate into distantly related keys by providing several more options for pivot chords.
- Sometimes composers will simply use a “pivot pitch” rather than a pivot chord to modulate. This affords more options for moving into distantly related keys.
- Dominant-seventh chords and German (and Italian) augmented-sixth chords are enharmonically equivalent. This allows you to use them as pivot chords into keys that are a semitone above or below the home key.
- Secondary dominant chords can also be used as pivot chords when they are enharmonically reinterpreted, making the options for modulation virtually limitless.
- Diminished-seventh chords can similarly be enharmonically reinterpreted, which means they can resolve four different ways into four different keys.
Chromatic Modulation
Modulation to closely-related keys is a relatively easy task; we can find a pivot chord by looking at the group of chords shared between two keys that have nearly-identical key signatures. There are plenty of them. See
When two keys are more than one accidental apart on the circle of fifths, however, it becomes more difficult it is to find a pivot chord that will enable a smooth modulation between the two keys.
To modulate to a distantly-related key, that is, a key that is more than one accidental away on the circle of fifths, requires us to use our knowledge of chromatic chords, such as those found through mode mixture. Mode mixture enables us to expand the number of possible pivot chords for modulation. For example, in the key of C major, the chords made possible through mode mixture (i.e. those chords found in C minor, its parallel key), we can now modulate easily to E-flat major (7 shared chords), A-flat major (4 shared chords), B-flat major (3 shared chords), and their relative minor keys, F minor and G minor.
shows the common chords shared between C major and E-flat major, made possible by using mixture chords in C major.
shows a modulation from the key of A major to F major, using iv from A major as a pivot chord. shows this technique being used by Verdi in his opera Rigoletto.
Conversely, we can use diatonic chords in the old key as mixture chords in the new key to modulate to distant keys in the “sharpwise” direction on the circle of fifth.
shows the potential pivot chords when modulating from C major to A major by way of the diatonic chords in C major as mixture chords in the new key of A major.
A modulation using this technique in a chorale setting is shown in
.
Modulation from A♭ major to C major using a diatonic chord in A♭ major (vi) as a pivot chord that is interpreted as a mixture chord (iv) in C major.
shows an interesting chromatic modulation from Brahms’s Waltz, op. 39, no. 14. Here, Brahms uses a diatonic viio6 chord in the local key of G major to pivot to E major, reinterpreting the chord as iio6, a mixture chord in the new key of E major.
Modulation from