Two voices both move upward from a perfect fifth to another perfect fifth. Which of the following best describes this?
AContrary motion, which is always acceptable
BParallel fifths, which collapse voice independence
COblique motion between the two voices
DSimilar motion that is permitted because the interval is consonant
When two voices move in the same direction and maintain the same interval class (a perfect fifth), this is parallel fifths — one of the two most strictly prohibited patterns in tonal voice leading. The independence of the voices merges perceptually, undermining the texture. Contrary fifths, where voices move in opposite directions and arrive at a fifth, are perfectly acceptable.
Question 2 True / False
A bass voice that leaps a perfect fifth between two chords violates standard voice-leading principles.
TTrue
FFalse
Answer: False
Bass leaps of a fourth, fifth, or octave are common and stylistically normal in four-part writing. The prohibition on parallel fifths applies to two voices moving together in the same direction maintaining a fifth — not to any single voice leaping a fifth. The bass has the most freedom to leap because it defines harmonic roots rather than carrying a melodic line.
Question 3 Short Answer
Why is contrary motion considered the strongest tool for maintaining voice independence?
Think about your answer, then reveal below.
Model answer: When voices move in opposite directions, they cannot simultaneously arrive at the same interval by parallel motion, which prevents parallel fifths and octaves structurally. The diverging paths also emphasize the distinctness of each line perceptually.
Parallel and similar motion both risk landing voices on the same interval class simultaneously, which is how parallel fifths and octaves arise. Contrary motion eliminates that risk by construction — if one voice goes up and the other goes down, they cannot be moving in parallel. This is why contrary motion is the default preference when independence needs reinforcing.