Mode mixture

Mode mixture refers to the use of chromatic chords that exist diatonically in the parallel major or minor mode. You may already be familiar with mode mixture in a handful of situations, such as the Picardy third (the major tonic chord at a cadence in a piece that is otherwise in a minor key) and the major dominant chord (V) in a minor key.

Mode mixture can occur at various levels in music. On a local level, individual chords may be borrowed from the parallel minor or major mode. We call these instances borrowed chords. Sometimes more material is based on the parallel major or minor: a group of chords, or even an entire phrase or section of music. Figure 40‑1 outlines the possible diatonic and borrowed chords in major and minor keys.

Of all possibilities, borrowed predominant chords are by far the most common (iio, iiø7, and iv) usually found in a major key, borrowing from the parallel minor. These add a special color and marked pathos to chord progressions in major keys that would otherwise sound ordinary.

Examples of borrowed chords

Example 40‑1, in a major key, uses one of the most common predominant borrowed chords, the borrowed subdominant triad from the parallel minor mode. In the fourth measure of the first phrase (0:09–0:22), the melody is harmonized with a diatonic subdominant chord (B major in the key of F major). The melody appears again later in 0:48–1:02, but now re-harmonized. Notice the borrowed subdominant (B minor) in the fourth measure of the re-harmonization.

Example 40‑2, also in a major key, uses the borrowed supertonic seventh chord, another common borrowed predominant. The German text of this passage translates in English to “I bear no grudge, even though my heart breaks.” We hear the expressive borrowed iiø7 on the word “Herz,” which means “heart” in German.

Example 40‑3 presents a compelling borrowed subdominant chord in the key of E major. In this excerpt, the borrowed minor iv (A minor) harmonizes the words “nothing really matters” in an otherwise major key context.

Example 40‑4 uses a repeating chord loop that features two chromatic chords. The repeating progression throughout the recording is G major – B major – C major – C minor. The final chord (C minor) is the borrowed minor subdominant chord (iv) in the overall key of G major. The B major chord is also chromatic, and it functions as a secondary dominant (V/vi) that resolves deceptively (VI/vi). It is also a chromatic mediant in relationship to the tonic triad.