Sound Design Sound 4 — Questions and Answers
Question 1: The equal-loudness contours (Fletcher-Munson curves) show that the human ear is LEAST sensitive to which frequency range at low listening levels?
- 1–4 kHz
- Low frequencies below 100 Hz and very high frequencies above 10 kHz (Correct answer)
- Mid frequencies around 500 Hz
- Frequencies around 3 kHz
Correct answer: Low frequencies below 100 Hz and very high frequencies above 10 kHz
At low SPL levels, the ear requires much more energy to perceive bass and extreme treble at equal loudness to midrange frequencies, as shown by the Fletcher-Munson curves.
Question 2: What is the primary perceptual correlate of a sound wave's amplitude?
- Pitch
- Timbre
- Loudness (Correct answer)
- Duration
Correct answer: Loudness
Amplitude (the peak displacement or pressure of the wave) primarily corresponds to the perceived loudness of a sound.
Question 3: Psychoacoustically, what phenomenon allows a loud sound to mask a quieter sound at a nearby frequency?
- Auditory fatigue
- Simultaneous masking (Correct answer)
- Pitch shifting
- The cocktail party effect
Correct answer: Simultaneous masking
Simultaneous masking occurs when a loud sound raises the threshold of hearing for quieter sounds at the same time, making nearby frequencies inaudible.
Question 4: Which cue does the human auditory system use to localize sound sources on the vertical (elevation) plane?
- Interaural time difference (ITD)
- Interaural level difference (ILD)
- Head-related transfer function (HRTF) spectral shaping (Correct answer)
- Binaural beats
Correct answer: Head-related transfer function (HRTF) spectral shaping
The outer ear (pinna) shapes the spectral content of incoming sounds differently depending on elevation; the brain interprets these HRTF cues to determine vertical position.
Question 5: The decibel scale is logarithmic. An increase of 10 dB corresponds to a perceived loudness that is approximately:
- Twice as loud (Correct answer)
- Five times as loud
- Ten times as loud
- One hundred times as loud
Correct answer: Twice as loud
Perceptually, a 10 dB increase is heard as roughly twice as loud, even though it represents a tenfold increase in sound power.
Question 6: What is the audible frequency range typically ascribed to healthy young adult humans?
- 20 Hz – 20,000 Hz (Correct answer)
- 200 Hz – 20,000 Hz
- 20 Hz – 2,000 Hz
- 20 Hz – 200,000 Hz
Correct answer: 20 Hz – 20,000 Hz
Humans with healthy hearing generally perceive sounds from approximately 20 Hz (low bass) to 20,000 Hz (20 kHz) in the high treble range.
Question 7: Temporal masking in audio perception includes 'forward masking,' which means:
- A quiet sound before a loud one masks the loud one
- A loud sound continues to raise the hearing threshold for a brief period after it ends (Correct answer)
- Two simultaneous sounds cancel each other
- Low frequencies mask high frequencies across time
Correct answer: A loud sound continues to raise the hearing threshold for a brief period after it ends
Forward masking occurs when a loud masker raises the auditory threshold for a short time after it ceases, making softer sounds immediately following it harder to detect.
Sound Design Sound 4
The equal-loudness contours (Fletcher-Munson curves) show that the human ear is LEAST sensitive to which frequency range at low listening levels?