Questions: Voice-Leading Direction Recognition by Ear

Question 1

In a four-voice chorale, the soprano rises from scale degree 7 to scale degree 1 while the bass falls from scale degree 5 to scale degree 1. What type of motion describes the relationship between these two voices?

• A. Parallel motion — both voices are moving, so they must be moving in parallel
• B. Oblique motion — one voice sustains while another moves
• C. Contrary motion — the soprano moves upward while the bass moves downward
• D. Similar motion — both voices arrive at the same pitch class (tonic)

Answer: (C)

Contrary motion occurs when two voices move in opposite directions — one ascends, one descends. The soprano rising (7→1) and the bass falling (5→1) is a textbook example: the outer voices converge toward the tonic from opposite directions. This convergent contrary motion is one of the most acoustically clear voice-leading events in tonal music and is characteristic of the perfect authentic cadence. Option A confuses 'both moving' with 'moving in parallel'; parallel motion requires the same direction.

Question 2

You hear two voices that seem to 'travel as one unit' — moving the same distance in the same direction throughout a passage. What voice-leading problem does this most likely indicate?

• A. Contrary motion — the voices are reinforcing each other's resolutions
• B. Parallel octaves or fifths — the voices are losing their independence and fusing acoustically
• C. Oblique motion — one voice is stationary and the interval between them remains constant
• D. Properly harmonized parallel thirds or sixths — this is a standard compositional technique

Answer: (B)

The key indicator of problematic parallel motion is that voices 'travel as a unit.' Parallel octaves cause the upper voice to be absorbed acoustically into the lower — the illusion of two independent voices collapses, and you effectively hear one doubled voice. Parallel fifths have a similarly hollow, archaic quality. Option D is a real distractor: parallel thirds and sixths are perfectly acceptable and produce the warm, full sound of harmonized melodies — the distinction is the interval. Fifths and octaves fuse; thirds and sixths don't.

Question 3

Contrary motion between soprano and bass is especially easy to hear because the outer voices physically move toward or away from each other in register.

• T. True
• F. False

Answer: True

The outer voices define the registral boundaries of the texture. When soprano and bass move in contrary motion, those boundaries expand (divergent contrary motion) or contract (convergent contrary motion) — a spatial event that is immediately perceptible even before individual pitches are identified. This is why ear training for voice-leading direction typically begins with outer-voice contrary motion: it is the most acoustically salient type.

Question 4

Parallel motion in thirds creates the same acoustic problem as parallel motion in octaves and should be avoided in good voice leading.

• T. True
• F. False

Answer: False

Parallel thirds are not only permitted but prized in tonal voice leading — they produce the warm, harmonically stable sound of harmonized melody lines (as in folk harmonizations or operatic duets). The problem is specific to parallel fifths and octaves, which cause voices to acoustically fuse, losing their independence. Thirds and sixths maintain distinct pitch content and separate perceptual streams. The rule against parallel motion is not a general rule; it targets the specific intervals where acoustic fusion occurs.

Question 5

Why do parallel octaves undermine good voice leading, while parallel thirds are considered acceptable or even desirable?

Model answer: Parallel octaves cause the upper voice to be acoustically absorbed into the lower — two voices moving at the octave sound like one doubled voice rather than two independent melodic lines. This destroys the textural independence that voice leading is designed to maintain. Parallel thirds keep distinct pitches in each voice and produce a harmonically warm, full texture where both lines remain perceptually separate. The key difference is acoustic fusion: octaves fuse; thirds do not.

This distinction is at the heart of classical voice-leading rules. The rules are not arbitrary — they describe acoustic phenomena. When voices fuse, you lose the counterpoint: instead of two lines in conversation, you have one thick line. This is acceptable in homophonic textures where voice independence is not the goal, but in polyphonic writing it is a loss of the texture's essential property. Thirds and sixths add harmonic color without sacrificing independence.