Sound Location & Binaural Hearing

Question 1

Spatial dimensions:

The source of sound can be localized in 3 dimensions:

Sound has ___ spatial dimensions

Answer 1

L -R (horizontal)
Up-down (vertical)
Near-far (range)

NO

Question 2

We localize sound using cues such as:

Answer 2

Time of arrival of sound @ ear

Intensity level

Frequency cues

Question 3

Interaural time difference (ITD)

Answer 3

The difference in time of arrival @ each ear

Question 4

If Called from the left, voice will reach ____ ear first and you will turn to the ______.

Answer 4

Left

Left

Question 5

Due to characteristics of sinusoids, if 2 sounds arrive at different times their ______ will be different at each ear

Answer 5

Phase

Question 6

Interaural intensity difference (IID)

Sound reaching the R ear first sounds ______ at right ear than left ear because of the ________.

Answer 6

Louder

Inverse square law

Question 7

Frequency differences will cause differences in ________ as well.

Higher frequencies blocked by ______________ .

Answer 7

Intensity

Size and shape of person’s head

Question 8

Low frequencies will _____ around head more easily because low frequencies travel _______ ________, high frequencies can’t.

Answer 8

Bend

Around corners

Question 9

Higher frequencies ______ intensity trying to get around the head. Therefore, easier for listeners to determine location of low and high frequency sounds.

Answer 9

Lose

Question 10

Hard to determine location of _____ frequency sounds at approx. ________Hz

Answer 10

Mid

2000

Question 11

Duplex theory of Localization:

2 cues to determine where sound is coming from:

Answer 11

The interaural TIME difference (ITD)

The interaural intensity difference (IID)

Question 12

ITD =

Answer 12

Interaural time difference

Which ear receives the sound first?

Provides info for low frequencies below 1666Hz

Question 13

IID =

Answer 13

Interaural intensity difference

Which ear gets the louder signal?

Provides info about higher frequencies

Question 14

The “cone of confusion”

Answer 14

Sounds which come from directly in front or behind have NO ITD or IID

Have to make small adjustments to head to localize

Question 15

Localization of the vertical plane

Components of the _______ _____ also contribute to localization

Answer 15

External ear

Question 16

Ears act as :

Answer 16

Small shadows and amplifiers causing ITDs and intensity differences particularly for higher frequencies

Seem most useful in vertical plane, although in general, localization in vertical planes is poorer than horizontal

Question 17

Binaural effect

Binaural summation threshold:

Answer 17

Slight improvement in hearing threshold (about 3dB on average with 2 ears rather than just 1

Question 18

Precedence effect:

When a sound coming from 1 direction is quickly followed by an ______ from another direction, the perceived sound will be ________by the earlier sound.

The signal that arrives first determines the perceived location of the fused sound. This is referred to as :

Answer 18

Second
Dominated

Echo suppression

Question 19

Speech benefits of the precedence effect:

Answer 19

Suppresses the effects of reflections that might interfere with perception of a sound

Question 20

Reflections that arrive beyond the time when the precedence effect oxides results in the ______ .

2 types :

Answer 20

Making of a signal

Late and early reverberation

Question 21

Lateralization

When you test user headphones you don’t have the advantage of the ________ to enhance the signal.

Answer 21

Outer ear

Question 22

Headphone tests

Answer 22

Can control time of arrival to each ear, phase and intensity independently

Listener usually perceives the tone as an image in their head

Question 23

Localization occurs __________ , while Lateralization occurs __________.

Answer 23

Environment

Headphones

Question 24

Lateralization (headphones)

If difference between 2 stimuli is great, the listener will hear 2 diff. Sound and the __________ won’t _______.

Answer 24

Image

Fuse

Question 25

A ITD greater than 2ms will result in :

Answer 25

A perception of 2 separate tones

Question 26

The “cocktail party effect”

Ability to:

Answer 26

Discriminate sounds in background noise based on spatial separation

Brain makes small discrimination in spatial relationships between sound to allow us to determine the position of a sound as well as to attend to a particular sound when many are present

Question 27

You need both ears to be able to localize and use spatial separation cues

T/F?

Answer 27

True

Question 28

Hearing in Boise will be significantly impaired if you have any of these:

Answer 28

Cochlear implants
Unilateral HL
Unilaterally aided
Unilateral ME infection