Questions: Voice Leading Error Recognition and Correction

Question 1

A student corrects a parallel fifth by changing the soprano note in the current chord. The revision clears the parallel fifth, but the professor marks it wrong because the leading tone now resolves downward. What does this reveal?

• A. Parallel fifths and leading-tone resolution are unrelated rules that should be fixed independently
• B. Correcting a voice leading error in isolation can create a new violation; the leading tone constraint was broken because the fix didn't account for the voice's required forward motion
• C. The student should have changed the tenor rather than the soprano
• D. Leading tones are permitted to resolve downward in SATB writing when other constraints require it

Answer: (B)

This illustrates why constraint propagation is the right mental model. The error appeared at a specific chord but was caused by earlier choices. Patching it locally shifted the soprano to a note that violated the leading-tone rule. A correct solution requires tracing all constraints forward and finding a soprano assignment that satisfies both the parallel-motion constraint and the resolution requirement — which may require rethinking a chord or two earlier.

Question 2

What is the underlying reason that parallel perfect fifths and octaves are prohibited in SATB voice leading?

• A. They produce a dissonant acoustic effect that was banned by Baroque counterpoint treatises
• B. They violate harmonic rhythm conventions by doubling chord tones too prominently
• C. They cause two independent voices to momentarily fuse acoustically into a single doubled line, erasing the listener's perception of distinct voices in dialogue
• D. They create forbidden cross-relations between voices of different ranges

Answer: (C)

The prohibition is not about dissonance — perfect fifths and octaves are actually consonant. The problem is voice independence: when two voices move in the same direction by the same proportional interval, they temporarily merge into one doubled voice. The listener stops hearing two independent melodic lines and hears one line doubled. All voice leading principles ultimately serve this goal: maintaining the integrity and independence of each part.

Question 3

Voice leading errors can typically be fixed locally — changing a note within the chord where the error occurs is sufficient to correct any voice leading violation.

• T. True
• F. False

Answer: False

Many errors are inevitable consequences of choices made one or more chords earlier. A seventh that was introduced without preparation must resolve downward; if the voice has no natural downward path, the problem exists in the chord where the seventh first appeared, not just where it fails to resolve. Similarly, a leading tone in the wrong voice often can only be fixed by reassigning the leading tone in a prior chord. Fixing one location may simply relocate the error.

Question 4

Voice crossing is best detected by tracing each voice horizontally as an independent melody and watching for registral violations, rather than by examining each vertical chord separately.

• T. True
• F. False

Answer: True

Vertical analysis of each chord shows whether the current voicing is correct but can miss the relationship between successive chords. Horizontal tracing — following each individual voice line — makes it immediately apparent when a lower voice moves above a higher one (crossing) or when a voice moves higher than the previous position of the voice above it (overlap). These are spatial violations only visible in the horizontal dimension.

Question 5

Explain why 'constraint propagation' is a better mental model for correcting voice leading errors than 'fix the rule that was broken.'

Model answer: Each note in a voice leading passage creates constraints on the notes that follow: a seventh must resolve down by step, a leading tone must resolve up, a doubled note must not create awkward parallels. Fixing an error at the point it appears often violates a constraint created by what comes next. Constraint propagation means tracing all such forward dependencies and finding a solution that satisfies all of them simultaneously — which usually requires revising an earlier chord, not just patching the flagged note.

The rule-based view treats each error as a local violation to patch. The constraint-propagation view treats the passage as a system of interconnected requirements. An error at measure 4 is often not a mistake at measure 4 but the inevitable result of a choice at measure 2. Understanding this is the difference between a student who can avoid marked errors and one who can write voice leading that flows naturally from beginning to end.