Midterm 1 - Topic 4

Question 1

Relation between pitch and loudness

Answer 1

Pitch and loudness have a complex relation with each other

Question 2

How is the relation between pitch and loudness best illustrated?

Answer 2

By a graph presenting equal loudness contours

Question 3

What does an equal loudness contour reflect?

Answer 3

The adjustment of given sound in terms of intensity to match the intensity of a standard tone

Question 4

What kind of function represents the relation between pitch and loudness

Answer 4

Quintic function

Question 5

Sound localization cues

Answer 5

Interaural time difference
Interaural intensity difference
Phase difference
Sources of ambiguity

Question 6

Interaural time difference

Answer 6

Difference in the distance a sound has to travel to get to both ears

Question 7

Can interaural time difference be quantified?

Answer 7

Yes

Question 8

Interaural intensity difference

Answer 8

Reflects the fact that sound reaches the two ears at different intensities

Question 9

How does threshold level relate to interaural intensity difference?

Answer 9

If stimulus is just at threshold presented to one ear, the other ear will not be able to hear it

Question 10

How does the head relate to interaural intensity difference?

Answer 10

The head produces a sound shadow that further reduces the intensity of the sound for the ear on the opposite side from the sound source

Question 11

When is the intensity difference between the two ears the strongest?

Answer 11

High frequency sounds

Question 12

Phase difference

Answer 12

Sound reaches the two ears at different phase angles

Question 13

When can interaural intensity difference not be used? Why?

Answer 13

For frequencies below 1000 Hz
Absorbed by the head

Question 14

When is phase difference useful? Why?

Answer 14

For frequencies lower than 4000 Hz
Size of the human head corresponds to a wave of about 4000 Hz

Question 15

Relation between sources of ambiguity and complex sounds

Answer 15

Sources of ambiguity are not a real problem for complex sounds
Unless they fall within the “cone of confusion”

Question 16

Cone of confusion

Answer 16

Sound sources at any location on that cone should theoretically send very similar info to each ear

Question 17

Azimuth

Answer 17

Angle around our head

Question 18

Elevation

Answer 18

How high the sound is in relation to our ears

Question 19

2 ways to resolve location ambuguity

Answer 19

Move your head
Shape of the pinna

Question 20

Shape of pinna and sound perception

Answer 20

With its ridges and valleys, it forces the sound waves to bounce around
The exact pattern of delay helps in the encoding of sound location
The intensity of the sounds is also affected, depending on their location and frequency

Question 21

Why should we care about sound localization?

Answer 21

Understanding how to optimize your sound localization abilities could save your life!

Question 22

3 cues to sound distance

Answer 22

Loudness
Spectral composition
Reverberation

Question 23

Loudness as a sound cue

Answer 23

The louder the closer
The exact pattern of delay helps in the encoding of sound location
This cue is more effective for sounds that are fairly close to us (within about 1 m)
The difference in intensity between two sounds decreases as distance increases

Question 24

Spectral composition as a sound cue

Answer 24

High frequencies are absorbed as sound travels through the air more than low frequencies
A sound that is far away has fewer intense high frequency components than a near sound

Question 25

Give an everyday example of spectral composition as a sound cue

Answer 25

Hear bass in music from cars playing loud music far away, but the higher frequencies only when the car is closer

Question 26

Reverberation as a sound cue

Answer 26

Short for "relative amount of reverberated vs. direct sound energy" Reverberated energy comes to us from more angles than direct energy Distant sources produce more reverberated energy than near sources The amount of reverberated energy allows us to estimate distance

Question 27

Why should we care about sound distance?

Answer 27

Ask yourself that the next time you cross the street into incoming traffic

Question 28

2 extra components of complex waves

Answer 28

Attack and decay

Question 29

Attack AKA?

Answer 29

How quickly a sound reaches its peak intensity Onset time

Question 30

Decay AKA?

Answer 30

How quickly a sound fades away Offset time

Question 31

Auditory scenes Who coined the term?

Answer 31

Combination of sounds at any point in time Bregman

Question 32

Biggest task in auditory scene analysis? Name?

Answer 32

Determining what parts of the scene belong together Auditory stream segregation

Question 33

What does auditory stream segregation rely on? What does this determine?

Answer 33

Principles of perceptual organization developed by Gestalt psychologists in the early 1900s Principles determine if we perceive all sounds as one or more streams

Question 34

Gestalt principles of perceptual organization that apply to auditory stream segregation

Answer 34

Proximity Similarity Good continuation Closure Common fate

Question 35

Proximity

Answer 35

Distances between auditory features wrt onsets, pitch, and loudness Features are grouped when they are close to each other but far from elements of another group Temporal and pitch proximity are competitive criteria

Question 36

Similarity

Answer 36

Sounds that are similar in timbre, frequency, or onset tend to be grouped together

Question 37

Good continuation

Answer 37

Identifies smoothly varying frequency, loudness, or spectra with a changing sound source Abrupt changes indicate the appearance of a new source

Question 38

Closure

Answer 38

Manifestation is called a restoration effect Completes fragmentary features that already have a "good Gestalt" Completion can be understood as an auditory compensation for masking Also works for speech sounds: Phonemic restoration effect

Question 39

Common fate

Answer 39

Groups frequency components together, when similar changes occur synchronously E.g., instead of perceiving one continuous stream, we perceive two streams: One starting at a high frequency and decreasing; one starting at a low frequency and increasing Groups these frequency components together

Question 40

Why should we care about auditory scene analysis?

Answer 40

Interesting, auditory stream segregation becomes more difficult as we age Knowing the principles at play might help you later