Voice Leading Rules

Why This Matters

Voice leading is the connective tissue of tonal harmony—it's what transforms a series of isolated chords into a coherent musical statement. When you're analyzing Bach chorales, Mozart string quartets, or even pop progressions, you're being tested on your ability to recognize why certain voice movements sound polished while others sound clunky or amateurish. The principles here govern independence of voices, smooth melodic motion, and proper treatment of dissonance, all of which appear repeatedly in part-writing exercises and analytical questions.

Don't just memorize a list of "don'ts." Instead, understand the underlying acoustic and perceptual reasons behind each rule. When you know why parallel fifths weaken texture or why the leading tone demands resolution, you can apply these concepts flexibly—whether you're completing a figured bass, analyzing a chorale, or identifying errors in a given passage. These rules aren't arbitrary; they're the grammar of tonal music.

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Preserving Voice Independence

The fundamental goal of voice leading is maintaining distinct melodic lines that work together without collapsing into each other. When voices move in ways that obscure their individuality, the texture loses depth and the ear struggles to track separate parts.

Avoid Parallel Fifths and Octaves

• Parallel perfect intervals fuse voices acoustically—the overtone series causes fifths and octaves moving together to blend into a single perceived line
• Independence disappears when two voices consistently maintain the same interval, undermining the four-part texture you're trying to create
• Exam tip: Look for these between any pair of voices, not just soprano and bass—they're equally problematic in inner voices

Avoid Hidden (Direct) Fifths and Octaves

• Similar motion into a perfect interval creates a weaker version of the parallel problem, especially between outer voices
• The ear anticipates the arrival at a fifth or octave, making the voices briefly merge in perception
• Most problematic when both voices leap; stepwise motion in the upper voice typically makes hidden intervals acceptable

Avoid Voice Crossing

• Crossing occurs when a higher voice dips below a lower one—this confuses the listener's tracking of individual lines
• Registral identity is how we distinguish soprano from alto from tenor from bass; crossing disrupts this clarity
• Brief crossings in inner voices are sometimes tolerated, but outer voice crossings are almost always flagged as errors

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Managing Tendency Tones and Resolution

Certain scale degrees carry inherent melodic energy that demands specific resolution. The leading tone ($\hat{7}$) and chordal sevenths create tension that must resolve for the phrase to feel complete.

Resolve Tendency Tones Properly

• The leading tone pulls toward tonic with gravitational force—leaving it unresolved creates an unsatisfied expectation
• Chordal sevenths resolve downward by step, releasing the dissonance they create against the chord root
• Active tones ($\hat{4}$, $\hat{6}$, $\hat{7}$) generally move toward stable tones ($\hat{1}$, $\hat{3}$, $\hat{5}$)

Resolve the Leading Tone to the Tonic

• In outer voices, resolution is mandatory—an unresolved leading tone in the soprano sounds incomplete
• Inner voice exceptions exist: the leading tone may leap to the fifth of the tonic chord to allow complete voicing
• Frustrated leading tones (moving down to $\hat{5}$) occasionally appear in inner voices but should be identified as exceptional

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Creating Smooth Melodic Motion

Good voice leading minimizes unnecessary movement while maintaining interest. The principle of parsimony—moving each voice as little as possible—creates cohesion without sacrificing musical vitality.

Maintain Common Tones Between Chords

• Common tones stay in the same voice when moving between chords, providing continuity and reducing unnecessary motion
• Root movement by fifth guarantees one common tone; root movement by third provides two
• Exam strategy: When part-writing, identify common tones first, then move remaining voices by step

Avoid Melodic Leaps Larger Than an Octave

• Leaps beyond an octave break the sense of a continuous melodic line—the voice seems to "restart" rather than continue
• Singability matters: these rules originated in vocal music where large leaps strain performers
• Compound intervals (larger than an octave) should be reduced to their simple equivalents when analyzing melodic motion

Keep Voices Within Their Proper Ranges

• Standard ranges ensure clarity: soprano ($C_4$ to $G_5$), alto ($G_3$ to $D_5$), tenor ($C_3$ to $G_4$), bass ($E_2$ to $C_4$)
• Overlapping ranges between adjacent voices are normal, but each voice should stay primarily in its own tessitura
• Extreme registers cause strain and change tone quality, disrupting the balanced texture

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Balancing Texture and Completeness

The overall sound depends on strategic distribution of chord tones and thoughtful motion between outer voices. These rules ensure the harmony sounds full while the texture remains interesting.

Use Contrary Motion Between Outer Voices

• Soprano and bass moving in opposite directions creates maximum independence and registral expansion
• Balance and stability result from voices pulling away from each other rather than collapsing inward
• Not always possible, but contrary motion should be the default choice when the harmony allows it

Use Complete Chords (Include All Chord Tones)

• All members of the triad (root, third, fifth) should appear for full harmonic realization
• The fifth may be omitted to double the root, but never omit the third—it defines chord quality
• Seventh chords require all four tones, though the fifth is again the most expendable member

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Quick Reference Table

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Self-Check Questions

1. Both parallel fifths and hidden fifths involve perfect intervals—what distinguishes them, and which is considered the more serious error in all contexts?

2. Which two rules both serve the goal of maintaining voice independence, and how do they approach this goal differently (one addressing interval relationships, one addressing register)?

3. If you're connecting a $V$ chord to a $I$ chord and the leading tone is in an inner voice, what are your two options for resolving it, and when is each appropriate?

4. Compare the treatment of common tones with the use of contrary motion: in what situation might these two principles conflict, and which typically takes priority?

5. You're analyzing a chorale and notice the tenor briefly dips below the bass before returning to its normal range. Is this automatically an error? What factors would you consider in your assessment?