This type of modulation uses a chord that is diatonic in both keys to pivot from the first key to the second. It is always followed by a harmonic progression clearly establishing the new key area.
2. Chromatic Inflection
Usually a single note is altered chromatically to help establish the new key. Often times the chromatic alteration involves introducing the new leading tone.
3. Phrase Modulation (Direct Modulation or Tonal Shift)
A phrase modulation takes place between phrases or sections. It can be rather abrupt and there is typically no apparent common chord or any other link or process helping to establish the new key.
4. Monophonic Modulation
The modulation occurs with a single, unaccompanied melodic line. It is often followed by a cadence confirming the new key.
5. Common Tone Modulation
A single note is heard between passages in two different keys. the common tone is generally part of chords in both keys and serves as a link between them. It will typically occur between two phrases.
6. Sequential Modulation
A harmonic and melodic pattern is repeated in a sequential manner, usually through several key areas, and arriving at (and establishing) a new key by the end of the sequence. Music Sources 12.A.2, pg. 104 (Carissimi) contains an example of a modulating sequence.
7. Enharmonic Modulation
This type of modulation involves the enharmonic respelling of a note or chord in order to lead to a new key area. This always requires a very clear and specific description of what is being respelled and how it leads to the new key. Music Sources 12.B.9, pg. 136-7 (Schubert) is a good example of an enharmonic modulation.
