Harmonic functions in minor

In classical harmony, usually the same chords are used in major and in minor with the same functions. For example, T1 S4 D5 T1 (I IV-or-II V I) is common in both modes, though the quality of chords will change. In rock/pop music, especially that of the last 20 years or so, there are some common differences in the normative harmonic patterns of major and minor modes.

For instance, the most common S–D progression in major is IV–V. While this is also common in minor, there is another common S–D progression that is far more common in minor than major: bVI–bVII. Thus the typical cadential bass line of fa–sol–do is replaced by le–te–do. In other words, Dm–E(m)–Am is replaced by F–G–Am.

Where minor-key songs with IV–V–I bear a stronger resemblance to their parallel major (sharing the same bass syllables and Roman numerals), songs that employ this bVI–bVII–I progression bear a stronger resemblance to the relative major (sharing the same bass notes and actual chords).

For example, the common S–D–T progression in C major is F–G–C. In A minor, the same functional progression could be F–G–Am.

Songwriters like U2 (“One”) take advantage of this relationship in songs where the verse and chorus modules are in different keys. In both cases, the verse is in minor and is based on a chord progression that ends bVI–bVII, followed by a return to I at the beginning of the next phrase. In both cases, the chorus begins on I in the relative major, turning the bVI–bVII in the minor key into IV–V in the major key. This two-key approach with VI–VII / IV–V as “pivot” point has become increasingly common in recent years.