Distant Modulation

During the Baroque and early Classical periods most modulations would be to the dominant, subdominant or relative key. Modulation to these “close” keys is relatively straightforward, because two close keys share most of the notes of their scales.

Modulating to any key is possible, however. From the late Classical period and onwards, composers became increasingly adventurous, exploring more distant modulations to create new types of harmonic structure in music.

Schubert (1797-1828) was an early pioneer of mediant modulations – moving to the key a third higher in major keys (e.g. C to Em), or the key a third lower in minor keys (e.g Am to F major). (Moving in the opposite direction simply takes you to the relative key, of course).

Mediant modulation keys are still relatively close, because the tonic chord of the new key shares two notes with the tonic chord of the old key, and also the tonic of the new key is a chord within the scale of the old key. For example, imagine modulating from C major to E minor. The new tonic chord is Em (E-G-B) which shares two notes with the old tonic chord of C (C-E-G).

Still connected, but more distant, are chromatic mediant modulations; the new tonic is still a third away, but the tonic chord is chromatically altered. Some examples could be C-Ab, or C-E. There is one common note between the tonic chord of the two keys, and this acts as a “pivot note”, smoothing the transition between the two chords. The pivot note normally stays within one part during both chords. The tonic of the new key is not the root of a diatonic chord in the old key.

Schubert’s Piano Sonata D.960 begins in Bb major. In bar 19, the second subject is introduced, and it is in Gb major – this is an example of chromatic mediant modulation. The pivot note common to both keys is Bb.

chromatic mediant modulation

Modulation to any distant key, even with no common note in the tonic chord, can be achieved by using the progression V7-I in the new key, or simply by restating an existing melodic unit directly in the new key with no dominant preparation (direct modulation).

By the 20th century, modulations to keys with no common notes are commonplace. For example, modulating from C major to F# major, or from C major to Eb minor.

Phrase Modulation

Repeating a phrase by direct modulation (without using the progression V(7)-I in the new key is known as “phrase modulation”.

Phrase modulation is common in “classical” music of all eras. In pop music, another typical type of direct modulation is the “semitone shift”. Roughly 2/3 of the way through a song, the pitch simply rises by one semitone, adding a greater sense of power/urgency to the music. One well-known example is the song Money, Money, Money by Abba. The song begins in A minor but shifts up to Bb minor for the last section.

Semitone shift modulations are often done with a key signature change, because the number of accidentals in the new key is sometimes unwieldy (going from A minor to Bb minor means an additional five flats!)