Fundamental frequency directly reflects the vibratory rate of the vocal folds and is an acoustic correlate of which attribute?

• A. vibratory amplitude; loudness
• B. vibratory amplitude; pitch
• C. vibratory rate; loudness
• D. vibratory rate; pitch

Answer: (D)

The main idea is how the speed of vocal fold vibration relates to pitch. The fundamental frequency is the rate at which the vocal folds vibrate each cycle, measured in cycles per second (Hz). This rate is the acoustic correlate of pitch because perceived pitch rises with faster vibration and falls with slower vibration. In other words, higher vibratory rate produces a higher pitch, while lower rate yields a lower pitch.

Loudness, on the other hand, comes from how much energy or amplitude the vocal folds generate, not from how fast they vibrate. So increasing amplitude increases loudness without necessarily changing pitch. This is why the option pairing vibratory rate with pitch is correct, while amplitude with pitch would be incorrect.