Diatonic Harmonic Function

Abstract One speaks of chord progressions, and these typically involve strongly harmonic relationships between the roots of the chords involved. But sometimes different chords appear in succession that have little or nothing to do with harmonic root relationships—sometimes, melodic concerns predominate, as when chords are fixed against a given melody, or when chords are chosen because some buried line can be heard moving through one chord tone into another as chords change, without regard to how any roots relate or even how the main melody moves. Sometimes this moving line occurs in the bass, and sometimes it is confined to inner parts, as in tones within chords on the guitar, piano, or backing vocals. (Listen to Web audio example 9.01.) These moving inner parts can be supported by what are called passing or neighboring chords, which connect more stable surrounding chords that may themselves have progressive root function whereas the chords between them have only a contrapuntal essence, existing only to provide a sonorous textural context for moving melodic lines. In our continuing investigation of harmony, we will take up in this chapter the issue of functional root motions, the progress of one chord to or through another, and the sorts of contrapuntal melodic relationships that can exist between and among chords. In chapters 10 and 11, we shall focus on the implications that nonmajor contexts may have for these basic relationships, and how mode mixture and chromatic harmony can color them further. Just as the more innocent and perhaps naïve quality of the major mode gradually became somewhat supplanted by modal systems in the rock music of the later ‘60s, our discussion will turn in due time from the harmonic implications of diatonic, major-mode functions to those of more revolutionary alternatives.