Psychoacoustics

Question 1

IAD

Answer 1

Interaural Amplitude Differences

Question 2

ITD

Answer 2

Interaural Time Differences

Question 3

ISD

Answer 3

Interaural Spectral Differences

Question 4

DEF: Interaural Amplitude Differences (IAD)

Answer 4

Rely on amplitude differences between the two ears

Question 5

DEF: Interaural Time Differences (ITD)

Answer 5

Rely on phase difference between the two ears

Question 6

DEF: Interaural Spectral Differences (ISD)

Answer 6

Rely on frequency differences between the two ears

Question 7

Sounds below approx. 1 kHz are perceived as _____ when played at high levels

Answer 7

lower

Question 8

Sounds above approx. 2 kHz are perceived as _____ when played at high levels

Answer 8

higher

Question 9

What’s another name for the Haas Effect?

Answer 9

The precedence effect; the law of first wavefront

Question 10

What is the Precedence/Haas Effect?

Answer 10

A binaural psychoacoustical effect where a sound is followed by another sound separated by a sufficiently short time delay, listeners perceive a single auditory event; its perceived spatial location is more or less determined by which ear receives the sound first.

Question 11

What is the doppler effect?

Answer 11

The apparent change in the frequency of a wave caused by the relative motion between the source of the wave and the observer

Question 12

If an object emitting sound waves is moving either toward or away from a stationary observer, how does that affect the frequency?

Answer 12

The soundwaves in front of the moving object bunch together and the sound waves behind the object spread out.

If the object is moving toward you the waves will be perceived at a higher frequency.

If the object is moving away from you, the waves will be perceived at a lower frequency.

Question 13

What is the formula for calculating the pitch shift from a moving source with a stationary listener?

Answer 13

F = (c/c-Vs)Fo

Question 14

What is the McGurk effect?

Answer 14

A perceptual phenomenon that occurs when the visual information a person gets from seeing a person speak changes the way they hear the sound.

Question 15

What is the cocktail party effect?

Answer 15

When a listener can focus on one particular stimulus or sound amongst various other stimuli, like a party goes focusing on one conversation at a cocktail party.

Question 16

DEF: pitch (psychoacoustics)

Answer 16

a psychoacoustic phenomenon (like hot or cold, bitter or sweet), synthesized for our brain by the auditory cortex system.

Question 17

DEF: timbre (psychoacoustics)

Answer 17

the colour or tone quality of a sound that allows instruments in the same family to be differentiated from each other

Question 18

DEF: equal-loudness contours

Answer 18

a measure of dB SPL over the frequency spectrum for which a listener perceives a constant loudness.

Question 19

Loudness is measured in

Answer 19

phon

Question 20

equal-loudness contours are also referred to as

Answer 20

Fletcher Munson curves

Question 21

how do humans perceive distance of a sound source?

Answer 21

sound spectrum - low frequencies travel farther than high frequencies

direct/reflection ratio - The ratio between direct sound and reflected sound can give an indication about the distance of the sound source.

loudness - closer sources are louder than farther ones

ITDG (initial time delay gap) - the time difference between arrival of the direct wave and first strong reflection at the listener. Nearby sources create a relatively large ITDG, with the first reflections having a longer path to take, possibly many times longer. When the source is far away, the direct and the reflected sound waves have similar path lengths.

Level Difference - very close sound sources cause a different level between the ears

Question 22

DEF: ITDG

initial time delay gap

Answer 22

the time difference between arrival of the direct wave and first strong reflection at the listener. Nearby sources create a relatively large ITDG, with the first reflections having a longer path to take, possibly many times longer. When the source is far away, the direct and the reflected sound waves have similar path lengths.