Summary of Unit 4 AP Music Theory: Explanation And Key Topics

AP Music unit 4 topics

If you’re studying for the AP Music Theory exam, mastering Unit 4 is crucial. This unit dives deep into harmony, voice leading, and chord progressions—essential concepts for analyzing and writing music. In this guide, we’ll break down everything you need to know, with clear explanations and examples.

Key Topics in Unit 4 AP Music Theory

1. Harmony & Chord Progressions

Triads & Seventh Chords: Understanding major, minor, diminished, and augmented triads, as well as dominant, major, and minor seventh chords.
Roman Numeral Analysis: Labeling chords using Roman numerals (I, IV, V, etc.) to show their function in a key.
Cadences:
- Authentic (Perfect & Imperfect)
- Plagal (Amen Cadence)
- Half Cadence
- Deceptive Cadence

2. Voice Leading Rules

Smooth Motion: Stepwise movement is preferred over leaps.
Common Tone Retention: Keep a common note between chords when possible.
Avoid Parallel Fifths & Octaves: These can weaken harmonic independence.
Resolving Leading Tones: The leading tone (7th scale degree) should resolve up to the tonic.

3. Four-Part Writing (SATB)

Soprano, Alto, Tenor, Bass (SATB) Voice Ranges
Doubling Rules:
- In root position triads, double the root.
- In first inversion, double the soprano or bass.
Spacing Rules:
- No more than an octave between upper voices (S, A, T).
- Bass can be farther from the tenor.

4. Non-Chord Tones (NCTs)

Passing Tone (PT): Steps between two chord tones.
Neighbor Tone (NT): Steps away and back to the same note.
Suspension (SUS): Holds a note, then resolves down.
Appoggiatura (APP): Leaps to a dissonance, then resolves by step.
Escape Tone (ET): Steps away, then leaps in the opposite direction.

5. Harmonic Progression & Functional Harmony

Tonic (I): Stability, “home” chord.
Predominant (IV, ii): Leads to the dominant.
Dominant (V, vii°): Creates tension, resolves to tonic.
Circle of Fifths Progressions: Common sequences like I-IV-vii°-iii-vi-ii-V-I.

Exam Tips for Unit 4

✔ Practice Roman numeral analysis with real music excerpts.
✔ Memorize cadence types and their resolutions.
✔ Follow voice-leading rules to avoid losing points.
✔ Identify non-chord tones in melodic lines.

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