Modal mixture is the technique of blending chords from a song’s primary mode with chords from a parallel mode — a scale that starts on the same root note but uses a different pattern of intervals. This approach expands the harmonic palette of a piece by introducing non-diatonic chords that offer fresh colors and emotional contrast.
For example, a song in C major might briefly use chords from C minor, such as the minor iv or ♭VII, to create a moment of darkness or poignancy before returning to the brightness of the major key. These inserted chords do not signal a full key change but instead serve as expressive detours that enrich the harmonic landscape.
The individual chords borrowed from the parallel mode are called borrowed chords, and their use together constitutes modal mixture. This technique is especially common in pop, rock, and classical music, where it helps convey subtle shifts in mood without disrupting the overall key of the piece.
Modal mixture is one of the most common ways that songs step outside the basic set of diatonic chords while still feeling connected to the home key.