Common-Tone Modulation
Holding one note to stitch the old key to the new
Related
Common-tone modulation seizes a pitch that belongs to both keys and keeps it sounding or repeating, stitching the old key to the new. The note is one scale degree in the old key and another in the new, and the ear follows it through the turn.
It often works with a diminished seventh or augmented sixth: the common tone stays while the other voices move by semitone, and the chord quietly changes identity. Unlike pivot-chord modulation, the shared element is a single note, not a whole chord, so the join is harder to hear.
To call it a modulation, the new tonic must still establish itself. If the common tone is only a decorative pedal and no new centre forms, the music has passed through, not moved.
Sources
- 共同音转调的手法与边界，参 The New Grove Dictionary of Music and Musicians, "Modulation"；本文为原创表述
Used for fact-checking only; all prose is original.