Harmony & Voice Leading I: Chord Function, Cadence & Phrase

Name: AP Music Theory Unit 4: Harmony & Voice Leading I: Chord Function, Cadence & Phrase
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2 lessons · 28 min18 terms

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What this unit covers

The topics below follow the published Music Theory course framework for Unit 4. Music Theory publishes no per-unit weighting, so there is no percentage to chase here.

CadencesVoice leadingPart-writingPhrases

Lessons in this unit

Diatonic Harmony, Function & Voice Leading15 min · 3 objectivesLabel diatonic triads in major and minor with Roman numerals · Classify chords by tonic, predominant, and dominant function · Apply core SATB voice-leading rules and spot common violations
Cadences & Phrase Structure13 min · 3 objectivesIdentify the cadence types by their chords and voicing · Distinguish perfect from imperfect authentic cadences · Describe phrases, periods, and antecedent–consequent structure

Formulas in Unit 4

Diatonic triads and function in major

I ii iii IV V vi vii° → T: I, vi · PD: ii, IV · D: V, vii°

Case shows quality (I major, ii minor, vii° diminished). Functional flow is T → PD → D → T; the dominant resolves the leading tone up to the tonic.

Cadence chord templates

PAC/IAC: V(7) → I · HC: … → V · DC: V → vi · PC: IV → I

PAC additionally requires both chords in root position and the soprano ending on do. Break either condition and V–I becomes an IAC.

Every term in Unit 4

All 18 terms we publish for Harmony & Voice Leading I: Chord Function, Cadence & Phrase, with definitions. Reading them through is the fastest way to find the ones you cannot define — then drill those in cram mode until you can produce them without the prompt.

The three harmonic functions: Tonic (I, vi, iii), predominant (ii, IV), dominant (V, vii°). Standard motion runs T–PD–D–T and rarely moves backward from dominant to predominant.
Why V does not go to IV: Retrogression weakens the drive to the cadence. The exception is the plagal extension after an authentic cadence, where the harmonic goal has already been reached.
Imperfect authentic cadence: V–I where the soprano does not land on the tonic, or where either chord is inverted. Weaker than a PAC and used mid-phrase.
Phrygian half cadence: iv6–V in minor, with the bass moving down a half step. A characteristic Baroque ending to a slow movement and recognizable by ear from that bass motion.
Period vs phrase: A phrase ends with a cadence; a period is two phrases where the first ends weakly and the second strongly. The weak-then-strong pairing is what makes it a period.
Parallel vs contrasting period: Parallel periods begin both phrases with the same material; contrasting periods do not. Labeled a–a′ against a–b.
Antecedent and consequent: The first phrase of a period is the antecedent, ending on a half or imperfect cadence; the consequent answers it with a PAC.
Double period: Four phrases where only the last closes with a PAC. Common in classical themes and a standard analysis question.
Sentence structure: Basic idea, repetition, then continuation and cadence, in a 1:1:2 proportion. Distinct from a period because it fragments and accelerates rather than answering.
Elision: The cadence of one phrase serves as the first beat of the next. Compresses the form and is heard as a phrase arriving early.
Parallel fifths and octaves: Two voices moving in the same direction while a perfect fifth or octave apart on both chords. The single most penalized error in part-writing, and it is checked between every pair of voices.
Direct (hidden) fifths and octaves: Both voices leaping in the same direction into a perfect fifth or octave, with the soprano leaping. Penalized between outer voices in particular.
Voice crossing and overlap: Crossing puts a lower voice above a higher one; overlap moves a voice past where an adjacent voice just was. Both are errors on this exam.
Resolving the leading tone: Scale degree 7 in an outer voice must rise to the tonic at a cadence. An unresolved leading tone in the soprano or bass is always marked.
Resolving the chordal seventh: The seventh of any seventh chord resolves down by step. It must also be prepared where possible, and it must never be doubled.
Frustrated leading tone: When 7 is in an inner voice at V–I it may fall to 5 so the tonic chord has a complete triad. Permitted only in an inner voice, never in soprano or bass.
Contrary, similar, oblique, parallel motion: The four relationships between two voices. Favoring contrary motion between soprano and bass prevents most parallel errors before they happen.
Cadence identification by ear: Listen to the bass and the final soprano note. Bass 5–1 with soprano on 1 is a PAC; bass 5–1 with soprano on 3 or 5 is an IAC; ending on 5 is a half cadence; 5–6 is deceptive.

What examiners penalize here

On part-writing questions, resolve **tendency tones** without fail: the **leading tone (ti) rises to do**, and the **chordal seventh falls by step**. In a V7–I in C, B (ti) goes to C and F (the seventh) goes to E. Missing either resolution is an automatic deduction.
In a parallel period, listen for the antecedent to end on a **half cadence (the question)** and the consequent to answer with a **PAC**. Identifying "HC then PAC" over two similar phrases is textbook evidence of a period — a frequent free-response and aural task.

Practice Music Theory

Our practice bank is drawn from across the whole course rather than filtered to one unit, which is closer to how the exam asks anyway — it will not tell you which unit a question is testing.

48 practice questionsEvery one with a written explanation FRQ trainerWritten answers scored against the rubric Music Theory study guideAll units, weights and score data in one place All 8 Music Theory unitsThe full course

Questions about this unit

How much of the AP Music Theory exam is Unit 4?

The Music Theory course framework does not publish a per-unit weighting, so there is no percentage to quote for Unit 4 and anyone who gives you one is guessing. Spread your time by where your own errors are instead.

What topics are covered in Music Theory Unit 4?

Harmony & Voice Leading I: Chord Function, Cadence & Phrase covers Cadences, Voice leading, Part-writing and Phrases. We publish 18 terms with definitions for this unit, all of them on this page.

How should I study Music Theory Unit 4?

Read the 2 lessons below first — about 30 minutes — then drill the 18 terms in cram mode until you can produce each definition from memory rather than just recognize it. Recognition is what makes a unit feel finished when it is not. Finish with practice questions and read the explanation for every one you get right by elimination as well as the ones you miss.

All 8 units of AP Music Theory

Unit names, topics and exam weights follow the published College Board course framework for AP Music Theory. AP® is a trademark registered by the College Board, which does not endorse this site.