Unit 4: Harmony and Voice Leading I

Executive Summary

Chords have jobs — tonic, predominant, dominant — and cadences mark phrase endings. Voice leading connects chords smoothly, and part writing follows its rules.

Chord function

Tonic (I) is stability and rest. Dominant (V) is tension resolving to tonic. Subdominant (IV) prepares the dominant. The functional order: tonic → predominant → dominant → tonic.

Cadences

Authentic: V-I. Perfect authentic (PAC): both chords in root position with the tonic in the soprano; imperfect (IAC): weaker positions. Plagal: IV-I ("Amen"). Half: ends on V — a pause. Deceptive: V-vi — a surprise.

Voice leading

Move voices smoothly: keep common tones, move by step, use contrary motion. Forbidden in common practice: parallel fifths and parallel octaves (they destroy independence). The leading tone resolves UP to the tonic; the seventh of V7 resolves DOWN by step.

Part writing (SATB)

Four voices: soprano, alto, tenor, bass. Upper voices stay within an octave of each other; bass and tenor may separate more. Double the root of root-position chords; never double the leading tone. Omit the fifth when needed in V7.

Exam traps

A half cadence ends on V, not I. Parallels are about ANY pair of voices moving in fifths/octaves. The leading tone rises even in deceptive resolutions.