What rules govern range, spacing, doubling and resolution when we write all four voices?
Topic 4.2 SATB Voice Leading: apply the rules of range, spacing, doubling, smooth motion and tendency-tone resolution when writing four-part harmony.
A focused answer to AP Music Theory Topic 4.2, covering the four-voice ranges, the spacing rule (no more than an octave between adjacent upper voices), doubling guidelines, the ban on parallels and voice crossing, and resolving the leading tone and tendency tones, with a worked voicing.
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What this topic is asking
The College Board (Topic 4.2) wants you to write four-part (SATB) harmony correctly: keep each voice in range, space the voices sensibly, double the right chord tone, move each voice smoothly, avoid parallels and voice crossing, and resolve tendency tones (especially the leading tone and chordal sevenths).
Range and spacing
Keeping these limits produces a balanced, singable texture. Cramming the upper voices together or opening a gap of more than an octave between alto and tenor makes the chord sound hollow or top-heavy.
Doubling and forbidden motion
These rules all serve one goal: four clearly independent, singable lines. The leading tone is the classic trap because doubling it almost guarantees a parallel-octave error on resolution.
Resolving tendency tones
The leading tone (degree 7) and the chordal seventh are tendency tones with fixed resolutions. The leading tone pulls up by step to the tonic, and in an outer voice it must do so. A chordal seventh pulls down by step to the next chord tone. Honoring these resolutions is what makes a dominant-to-tonic motion sound complete.
Why the rules produce good harmony
The central idea is that the SATB rules are not arbitrary; each one protects the independence and singability of the four lines. Range and spacing keep every part comfortable to sing and well balanced in sound. The doubling rules keep chords complete and avoid the parallel octaves that doubling a tendency tone would create. The motion rules keep the voices distinct so the ear hears four parts, not a blur. And the tendency-tone resolutions give the progression its sense of arrival. When you internalise the rules as servants of independence and resolution, you can voice-lead almost on autopilot: keep common tones, move the rest by the smallest step, resolve the leading tone up and the seventh down, and check the outer voices for parallels.
Voicing and resolving a chord
To part-write a chord, place the bass, then fill the upper three voices with the remaining chord tones (doubling a stable tone) within the spacing limits. To move to the next chord, keep common tones, move other voices by the smallest smooth interval, resolve any tendency tones, and check for parallels.
Try this
Q1. Why should you never double the leading tone in four-part writing? [1 point]
- Cue. Both leading tones resolve up to the tonic, producing parallel octaves.
Q2. What is the maximum spacing allowed between the soprano and alto voices? [2 points]
- Cue. No more than an octave; the same limit applies between alto and tenor, while tenor to bass may be wider.
Exam-style practice questions
Practice questions written in the style of College Board exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
AP 2022 (style)1 marksSection I (multiple choice, written). When a V chord moves to I in a major key, the leading tone in an outer voice should resolve how? (A) down by step (B) up by step to the tonic (C) stay on the same pitch (D) leap down a thirdShow worked answer →
The correct answer is (B) up by step to the tonic.
The leading tone (scale degree 7) is a tendency tone that pulls up a half step to the tonic. When it is in the soprano or bass, it must resolve up by step to scale degree 1; failing to resolve it leaves a harsh unresolved tendency and often causes a doubling problem.
(A) down by step would be wrong for the leading tone. (C) holding it leaves the tension unresolved. (D) a downward leap abandons the resolution entirely. The trap is forgetting that the leading tone in an outer voice is the strictest case; in an inner voice it may sometimes fall to the fifth of the tonic chord to keep a complete chord, but in soprano or bass it must rise.
AP 2023 (style)3 marksSection II (free response, part-writing). Voice the V chord in C major (G, B, D) in four voices with the root doubled, then resolve it to I (C, E, G), naming the pitch motion in each voice and confirming the leading tone resolves correctly.Show worked answer →
A 3-point part-writing question.
(1 point) Voice V as bass G2, tenor D3, alto G3, soprano B3 (root G doubled, third B, fifth D). The leading tone B is in the soprano.
(1 point) Resolve to I: bass G2 to C3 (root motion up a fourth), soprano B3 to C4 (leading tone up by step to the tonic), alto G3 stays as G3 (common tone), tenor D3 to E3 (down by step to the third).
(1 point) The leading tone B rises to C, no parallel fifths or octaves occur, and all voices move smoothly, so the resolution is correct.
Markers reward the leading tone rising to the tonic, keeping the common tone (G), moving the other voices by the smallest step, and avoiding parallels. Doubling the root of V is the safe choice; doubling the leading tone B would force parallel octaves on resolution.
Related dot points
- Topic 4.1 Soprano-Bass Counterpoint: write and identify the four kinds of motion between the outer voices and avoid parallel perfect intervals.
A focused answer to AP Music Theory Topic 4.1, covering the four types of motion (parallel, similar, contrary, oblique) between the outer voices, the ban on parallel perfect fifths and octaves, the preference for contrary motion, and starting and ending intervals, with a worked example.
- Topic 3.5 Roman Numerals and SATB: label diatonic chords with Roman numerals showing root and quality, and arrange chord tones in the SATB four-voice texture.
A focused answer to AP Music Theory Topic 3.5, covering Roman numeral analysis (case shows quality, figures show inversion), the diatonic numerals of major and minor keys, the SATB four-voice layout and ranges, and how to spell a chord across four voices, with a worked analysis.
- Topic 4.3 Harmonic Progression, Functional Harmony, and Cadences: explain tonic, predominant and dominant function, the normal direction of progressions, and the four cadence types.
A focused answer to AP Music Theory Topic 4.3, covering functional harmony (tonic, predominant, dominant), the normal flow tonic to predominant to dominant to tonic, and the four cadences (perfect authentic, imperfect authentic, half, plagal, with the deceptive cadence), with a worked cadence analysis.
- Topic 4.4 Voice Leading with Seventh Chords: part-write the dominant seventh and other seventh chords in root position, resolving the chordal seventh and leading tone correctly.
A focused answer to AP Music Theory Topic 4.4, covering part-writing the dominant seventh in root position, resolving the chordal seventh down by step and the leading tone up, the option of an incomplete chord to avoid parallels, and preparing the seventh, with a worked resolution.
- Topic 1.4 Major Scales and Scale Degrees: construct a major scale using the whole and half step pattern, and identify scale degrees by number, name and solfege.
A focused answer to AP Music Theory Topic 1.4, covering the major scale step pattern (W W H W W W H), scale degree numbers, the functional names (tonic to leading tone), and movable-do solfege, with a worked scale build.
Sources & how we know this
- AP Music Theory Course and Exam Description — College Board (2024)