Soprano-Bass Counterpoint
Write a bass line under a given soprano using the four motion types, avoid parallel fifths and octaves, and end phrases with appropriate cadences including a final PAC.
AP Music Theory Unit 4 Review: Chord Function, Cadence, and Phrase
- 5 topics
- AP exam review verified for 2027
Unit 4 teaches you how chords move from one to the next in 18th-century style, what errors to avoid (parallel fifths, unresolved sevenths, voice crossing), how to identify cadences, and how to write or analyze two-voice and four-voice harmonic progressions.
Fiveable's AP Music Theory Unit 4 review covers 5 topics, with guided practice questions for the unit.
AP Music Theory unit 4 topics
SATB Voice Leading
Add alto and tenor voices to complete four-voice SATB textures, following rules for chord spelling, doubling, spacing, and motion to avoid errors like voice crossing and direct octaves.
Harmonic Progression, Functional Harmony, and Cadences
Identify tonic, dominant, and predominant function in chord progressions and recognize cadence types (PAC, IAC, HC, deceptive, plagal) in both notated and performed music.
Voice Leading with Seventh Chords
Apply approach and resolution rules for chordal sevenths in SATB writing, including omitting the fifth in root-position V7 and resolving the seventh down by step.
Voice Leading with Seventh Chords in Inversions
Realize inverted seventh chords (6/5, 4/3, 4/2) with complete spelling, no doubled tendency tones, and smooth stepwise bass motion, including leading-tone seventh chord substitutions.
Practice AP Music Theory unit 4 questions
Try AP-style questions on unit 4, then use the review notes below for anything you miss.
Unit 4 review notes
4.1
Soprano-Bass Counterpoint
Soprano-bass counterpoint focuses on the outer two voices of a four-voice texture. Given a soprano line, you write a bass line that implies a strong harmonic progression and ends with a perfect authentic cadence. The four motion types govern how the two voices relate at each chord change.
- Parallel motion: Both voices move in the same direction by the same interval. Parallel fifths and parallel octaves are prohibited.
- Contrary motion: Voices move in opposite directions. This is the preferred motion type for independence and is especially important between soprano and bass.
- Similar motion: Both voices move in the same direction but by different intervals. Avoid similar motion to a perfect fifth or octave in the outer voices (direct fifths/octaves) unless the upper voice moves by step.
- Oblique motion: One voice holds a common tone while the other moves. Useful for smooth connections when a chord tone is shared between adjacent harmonies.
- Bass line melodic conventions: Bass lines use leaps more than upper voices. Allowable leaps include thirds, perfect fourths and fifths, sixths, and octaves. Octave leaps should change direction. Successive leaps in the same direction must outline a triad.
Given a soprano line in C major, can you write a bass line that implies I, IV, V, and ii chords, avoids parallel fifths and octaves, and ends with a PAC (V-I, both root position, scale degree 1 in soprano)?
| Motion type | Direction of voices | Common use / note |
|---|---|---|
| Contrary | Opposite directions | Preferred for outer-voice independence |
| Similar | Same direction, different interval | Avoid to perfect fifth or octave unless upper voice steps |
| Parallel | Same direction, same interval | Parallel fifths and octaves are prohibited |
| Oblique | One voice stationary | Useful when a common tone is shared between chords |
4.2
SATB Voice Leading
SATB writing adds the alto and tenor inner voices to the soprano and bass. Every chord must be spelled correctly, spaced within the rules, and doubled according to convention. The same motion-type rules from Topic 4.1 apply, plus additional spacing and doubling requirements.
- Spacing rule: Adjacent upper voices (soprano-alto, alto-tenor) must stay within an octave of each other. The bass may be more than an octave below the tenor.
- Root doubling: Double the root of a triad whenever voice leading allows. Never double the leading tone or the chordal seventh.
- First inversion doubling: In first-inversion triads, the bass holds the third of the chord. Double the soprano note or the root, not the bass note, unless voice leading demands otherwise.
- Unequal fifths: A diminished fifth moving to a perfect fifth (rising unequal fifths) should be avoided. The exception is I-V4/3-I6, where this motion is acceptable.
- Consecutive thirds and sixths: No more than three consecutive harmonic thirds or sixths between any two voices. Vary the motion type to prevent monotony.
Realize the progression I-IV6-V-I in G major in SATB. Check: is every chord spelled correctly? Are upper voices within an octave? Is the root doubled in each triad? Are there any parallel fifths or octaves?
| Error type | What it is | How to fix it |
|---|---|---|
| Parallel fifths | Two voices move to a perfect fifth by the same interval | Change one voice's motion direction or interval |
| Parallel octaves | Two voices move to an octave by the same interval | Use contrary or oblique motion instead |
| Voice crossing | A lower voice moves above an adjacent upper voice | Keep voices in their proper range order |
| Doubled leading tone | The seventh scale degree appears in two voices | Double the root or fifth instead |
| Spacing error | Adjacent upper voices more than an octave apart | Redistribute inner voices to close the gap |
4.3
Harmonic Function and Cadences
Every chord in tonal music serves one of three functions: tonic (T), dominant (D), or predominant (PD). Progressions move logically from T to PD to D and back to T. Cadences are the harmonic formulas at phrase endings that create varying degrees of closure.
- Tonic function: Chords I and vi. Provide stability and a sense of home. Progressions typically begin and end here.
- Dominant function: Chords V and vii°. Create tension that resolves to tonic. The V7 chord is the strongest dominant because it contains both the leading tone and the chordal seventh.
- Perfect authentic cadence (PAC): V to I, both chords in root position, with scale degree 1 in the soprano. The strongest and most conclusive cadence type.
- Half cadence (HC): Any phrase ending on V. Inconclusive; creates a sense of pause that demands continuation.
- Deceptive cadence: V resolves to vi instead of I. The leading tone still resolves up, but the bass moves to scale degree 6 rather than 1, creating surprise.
Label the function (T, PD, D) of each chord in the progression I-ii-V7-I in D major. Then identify the cadence type at the end and explain why it is a PAC or not.
| Cadence type | Chord progression | Conclusive or inconclusive |
|---|---|---|
| Perfect authentic (PAC) | V-I, root position, scale degree 1 in soprano | Conclusive |
| Imperfect authentic (IAC) | V-I, inversion or non-root soprano | Conclusive (weaker) |
| Half cadence (HC) | Any chord to V | Inconclusive |
| Deceptive cadence | V to vi | Inconclusive |
| Plagal cadence | IV to I | Conclusive (softer) |
4.4
Voice Leading with Seventh Chords
Seventh chords add a dissonant fourth note above the triad. The chordal seventh requires careful approach and resolution in SATB writing. The dominant seventh chord (V7) is the most common seventh chord in tonal music and has specific part-writing conventions.
- Approach to the chordal seventh: Approach by common tone or by step. If those options are unavailable, an ascending leap is acceptable. A descending leap of a third is rare and used only when necessary.
- Resolution of the chordal seventh: The chordal seventh must resolve down by step to avoid an unresolved seventh. Exception: in I-V4/3-I6, the seventh in V4/3 may move up by step.
- Omitting the fifth in root-position V7: When writing V7 in root position in SATB, the fifth may be omitted and the root doubled. This allows the leading tone and chordal seventh to resolve correctly without creating parallel fifths.
- V7 to I resolution: After a complete root-position V7, the tonic triad may have three roots and a third (no fifth). The leading tone resolves up to scale degree 1 and the seventh resolves down to scale degree 3.
- Unresolved seventh: Leaving the chordal seventh without a downward step resolution is a voice leading error. Always check that the voice carrying the seventh moves down by step to the next chord.
Write V7-I in C major in SATB. Omit the fifth in V7 and double the root. Confirm the leading tone resolves up to C and the chordal seventh (F) resolves down to E. Check for parallel fifths.
4.5
Voice Leading with Seventh Chords in Inversions
Inverted seventh chords (6/5, 4/3, 4/2) allow the bass to move by step through a progression, creating smooth linear motion. Every inverted seventh chord must be spelled completely, tendency tones must not be doubled, and the chordal seventh still resolves down by step.
- Figured bass inversions: 6/5 = first inversion (third in bass), 4/3 = second inversion (fifth in bass), 4/2 = third inversion (seventh in bass). Each inversion places a different chord tone in the bass.
- Stepwise bass motion: Inverted seventh chords are often used in sequences where the bass moves by step (e.g., descending: I-V4/2-I6-IV6/5-I). This creates a smooth, linear bass line.
- Complete spelling required: Unlike root-position V7 where the fifth may be omitted, inverted seventh chords must include all four chord tones. No omissions are allowed.
- Leading-tone seventh chords: vii°7 (fully diminished) and viiø7 (half-diminished) can substitute for V or V7 as dominant function chords, or they can prolong the tonic when placed between two tonic chords with stepwise voice leading.
- No doubled tendency tones: In any inverted seventh chord, the leading tone and chordal seventh must each appear in only one voice. Doubling either tendency tone creates unresolvable parallel motion.
Realize the progression I-V4/2-I6 in A major in SATB. Confirm the bass moves by step (E down to D, then up to C#), the seventh in V4/2 resolves down by step, and no tendency tones are doubled.
| Inversion | Figured bass | Chord tone in bass | Key voice leading note |
|---|---|---|---|
| Root position | 7 | Root | Fifth may be omitted; double the root |
| First inversion | 6/5 | Third | Spell completely; no doubled tendency tones |
| Second inversion | 4/3 | Fifth | Spell completely; smooth voice leading in and out |
| Third inversion | 4/2 | Seventh | Seventh is in bass; upper voices resolve tendency tones |
Key terms
| Term | Definition |
|---|---|
| Parallel fifths | Two voices moving in the same direction to a perfect fifth by the same interval. Prohibited in 18th-century voice leading because it reduces voice independence. |
| Parallel Octaves | Two voices moving in the same direction to an octave by the same interval. Prohibited for the same reason as parallel fifths. |
| Contrary motion | Two voices moving in opposite directions. The preferred motion type between soprano and bass for maintaining voice independence. |
| Doubling | Assigning the same chord tone to more than one voice. The root is the preferred doubling choice; the leading tone and chordal seventh must never be doubled. |
| Tendency Tones | Scale degrees with strong directional pull: the leading tone resolves up by step to the tonic, and the chordal seventh resolves down by step. |
| Chordal Seventh | The note a seventh above the chord root. Must be approached by common tone or step and resolved down by step in 18th-century voice leading. |
| Perfect Authentic Cadence | V to I with both chords in root position and scale degree 1 in the soprano. The strongest and most conclusive cadence type. |
| Imperfect Authentic Cadence | A V-I progression where either chord is inverted or the soprano does not end on scale degree 1. Conclusive but weaker than a PAC. |
| Half Cadence | A phrase ending on V. Inconclusive; creates a sense of pause that requires continuation. |
| Deceptive cadence | V resolving to vi instead of I. The leading tone still resolves up, but the bass moves to scale degree 6, creating an unexpected outcome. |
| Roman numeral analysis | A system for labeling chords by their scale degree root and quality, with Arabic numerals added to show inversion. Used to represent harmonic progressions in tonal music. |
| Leading-tone Seventh Chords | vii°7 (fully diminished) and viiø7 (half-diminished) seventh chords built on scale degree 7. They function as dominant substitutes or prolong the tonic with stepwise voice leading. |
| Unresolved Seventh | A voice leading error in which the chordal seventh does not move down by step to the next chord, leaving the dissonance unresolved. |
| Spacing | The vertical arrangement of voices in SATB writing. Adjacent upper voices (soprano-alto, alto-tenor) must stay within an octave; the bass may exceed an octave below the tenor. |
| Direct Fifths and Direct Octaves | Similar motion in the outer voices to a perfect fifth or octave. Avoided unless the soprano moves by step into the interval. |
How to review unit 4
Topics students miss most
Miss rates come from Fiveable multiple-choice practice.
Mistakes to avoid in Chord Function, Cadence, and Phrase
Doubling the leading tone
In V or V7 chords, the seventh scale degree (leading tone) must appear in only one voice. Doubling it forces one copy to resolve incorrectly, usually creating parallel octaves when both copies resolve up to scale degree 1.
Leaving the chordal seventh unresolved
The chordal seventh must move down by step to the next chord. A common error is leaping away from the seventh or holding it as a common tone without eventually resolving it downward.
Omitting a tone in an inverted seventh chord
Unlike root-position V7, inverted seventh chords (6/5, 4/3, 4/2) must include all four chord tones. Omitting the fifth or any other tone in an inversion is a spelling error.
Confusing PAC and IAC
A perfect authentic cadence requires V-I with both chords in root position AND scale degree 1 in the soprano. If the soprano has scale degree 3 or 5, or either chord is inverted, the cadence is imperfect authentic, not perfect.
Creating direct (hidden) fifths or octaves
When outer voices move by similar motion to a perfect fifth or octave, the soprano must move by step. Moving the soprano by leap to a perfect interval with the bass is a direct fifth or octave error.
Chord Function, Cadence, and Phrase on the AP exam
Part-writing and error detection tasks
The AP Music Theory exam includes tasks where you complete an SATB progression from a given soprano, bass, Roman numerals, or figured bass, and tasks where you identify specific voice leading errors in a provided passage. Unit 4 rules (doubling, spacing, parallel motion, tendency tone resolution) are the direct content for both task types.
Harmonic dictation and outer-voice notation
The exam tests your ability to notate the soprano and bass lines of a performed harmonic progression and then provide Roman numeral analysis. Unit 4 trains you to hear cadence types, identify chord inversions from bass motion, and connect what you hear to functional harmonic labels.
Score analysis with Roman numerals and cadence identification
In score analysis tasks, you label chords with Roman numerals (including inversion symbols), identify harmonic function (T, PD, D), and name cadence types at phrase endings. Unit 4 provides the vocabulary and procedural knowledge needed to distinguish a PAC from an IAC, a half cadence from a deceptive cadence, and to explain why a specific chord progression is or is not stylistically correct.
Study unit 4 other ways
- Topic study guides
- Practice questions
- FRQ practice
- Cram archive videos
- Official unit cheatsheet
- Score calculator
Unit 4 printables
Print the unit cheatsheets ($3) for Unit 4. Yours to keep, no subscription needed.
get printablesFrequently Asked Questions
What's on the AP Music Unit 4 progress check (MCQ and FRQ)?
The AP Music Theory Unit 4 progress check tests voice leading and harmonic progression skills through both MCQ and FRQ parts. The MCQ section asks you to identify cadence types, analyze chord function (tonic, dominant, predominant), and spot voice leading errors in SATB writing. The FRQ section typically asks you to complete or correct a short SATB passage, resolve seventh chords properly, and label harmonic progressions. Every topic from 4.1 through 4.5 is fair game, so make sure you're solid on soprano-bass counterpoint, functional harmony, and seventh chords in inversions before you sit down for it. Practice questions matched to each topic are at /ap-music-theory/unit-4.
How do I practice AP Music Unit 4 FRQs?
AP Music Theory Unit 4 FRQs focus on voice leading tasks: writing or completing SATB passages, resolving seventh chords correctly, and labeling cadences within a harmonic progression. To practice, work through short four-part writing exercises that target each topic, then check your work against the standard voice leading rules (no parallel fifths or octaves, proper chord resolution). Start with Topics 4.2 and 4.3 since SATB voice leading and cadence identification show up most often in free-response questions. Once those feel solid, move to seventh chords (Topics 4.4 and 4.5), which add the extra step of resolving the chordal seventh down by step. Find topic-matched practice at /ap-music-theory/unit-4.
How should I study AP Music Unit 4?
Studying AP Music Theory Unit 4 well means building your voice leading skills in layers, starting with the rules before adding complexity. Here's a concrete plan: 1. Start with soprano-bass counterpoint (Topic 4.1). Get comfortable writing two-voice frameworks before adding inner voices.
2. Learn SATB voice leading rules (Topic 4.2). Drill the big errors to avoid: parallel fifths, parallel octaves, and voice crossing.
3. Study harmonic progression and cadences (Topic 4.3). Know how tonic, dominant, and predominant chords function, and be able to identify authentic, half, plagal, and deceptive cadences by ear and on paper.
4. Add seventh chords (Topics 4.4 and 4.5). Practice resolving the chordal seventh down by step in root position and all inversions. Review one topic at a time, write short four-part examples for each, and check them against voice leading rules. Consistent short practice sessions beat cramming every time. All five topics are at /ap-music-theory/unit-4.