Binaural Hearing

Question 1

What are the 3 dimensions you can localize sound in?

Answer 1

1.) Azimuth
2.) Elevation
3.) Distance

Question 2

What are the 2 categories of sound localization cues in azimuth?

Answer 2

1.) Time/Phase
2.) Intensity/Level

Question 3

What are interaural cues?

Answer 3

Locating the source of a sound by comparing the distance in arrival time of a sound between 2 ears

Question 4

What is range of sound where people have trouble hearing speech in noise?

Answer 4

1000-2000Hz

Question 5

If you remove high frequency information from the HRTF, what dimension can you not localize sound in?

Answer 5

Elevation

Question 6

How can atmospheric absorption affect sound?

Answer 6

Atmospheric absorption affects sound by gradually reducing its intensity as it travels through the air, primarily due to friction between air molecules which converts sound energy into heat, causing higher frequencies to be dampened more significantly than lower frequencies. This effect is influenced by factors like temperature and humidity levels in the atmosphere

Question 7

How does a response depend on how you ask a question about judging distance?

Answer 7

Judgment of perceived distance vs actual distance may depend on how you ask for a response - visual slider vs verbal report throwing out a number

Question 8

What is the minimum audible angle?

Answer 8

The smallest detectable difference in the direction of two sound sources that a person can reliably distinguish

Question 9

How is sound affected in an anechoic room?

Answer 9

Sounds have a rapid onset and short duration. There is no reverberation of sound in an anechoic room and sound is nearly completely absorbed by the walls.

Question 10

What is the precedence effect?

Answer 10

An acoustic signal arriving first at one ear masks/suppresses the ability to hear any other signals from the other ear

Question 11

What is Masking Level Difference?

Answer 11

The improvement in detecting a tone or speech in noise when the phase of the tone or the noise is reversed by 180 degrees. It works better with low frequencies, but not with high frequencies

Question 12

Who discovered Masking Level Difference?

Answer 12

Ira Hirsch in the 1940s

Question 13

What is the point of Auditory Aided Visual Search?

Answer 13

The ears are set up to be really good at localizing stimuli 4x faster than just using your eyes to location something.

Question 14

What is lateralization?

Answer 14

Our ability to study localization/lateralize sound using headphones

Question 15

What is a unique binaural signature?

Answer 15

A sound(s) based on our assessment of where the sound is in relation to azimuth, elevation, and distance.
Cues are based on interaural phase & intensity, HRTF, inverse square law for distance.
A unique sound signature for a particular person in a particular location.

Question 16

How do we utilize the Cocktail Party Effect?

Answer 16

We locate a person’s unique binaural signature to listen to one person in particular. This is about targets in noise.

Question 17

How much amplification does the HRTF provide?

Answer 17

20dB

Question 18

How do we externalize sound?

Answer 18

The sound sounds like it is coming from outside of your head. We use binaural cues from the HRTF for the brain to compare the left ear HRTF and the right ear HRTF to localize a sound. When the high frequency sound is taken away from the HRTF, it doesn’t sound like anything is happening outside of your head.

Question 19

What is extended high frequency hearing?

Answer 19

The ability to hear sounds at frequencies above 8000Hz, which are considered beyond the standard clinical hearing test range, and are often used to detect early signs of hearing loss, particularly related to aging or noise exposure

Question 20

What are the 3 types of listening?

Answer 20

1.) Monotic
2.) Diotic
3.) Dichotic

Question 21

Why would we use dichotic listening?

Answer 21

We are looking for what the person might say when a sound is presented slightly after another sound in presented in the other ear. If we send “pop” in one ear followed very quickly by “corn” we want to see if they respond with “pop”, “corn”, or “popcorn”.

This is used to investigate selective attention and the lateralization of brain function within the auditory system.

Question 22

What is the “right ear advantage”?

Answer 22

Since language is processed primarily on the left side of the brain and the brain works contralaterally, a sound presented to the right ear has a more direct path to the left hemisphere. A sound presented to the left ear would go to the right hemisphere and then have to cross the corpus collosum.

Question 23

How do we know what sounds belong together and what should be separated out?

Answer 23

We use unique binaural signatures and grouping principles to sort out what belongs together

Question 24

What are grouping principles?

Answer 24

The perceptual rules that govern how we organize auditory stimuli into coherent wholes, based on spectral/frequency cues, spatial cues, and temporal cues

Question 25

What are the 3 spectral/frequency cues in grouping principles?

Answer 25

1.) Spectral Separation
2.) Spectral Profile
3.) Harmonicity

Question 26

What are the 3 Temporal cues in grouping principles?

Answer 26

1.) Temporal Separation
2.) Temporal Onsets/Offsets
3.) Temporal Modulation

Question 27

What is Spectral Separation?

Answer 27

2 sounds that are similar in frequency will be perceived as belonging together. Sounds with different frequencies will be perceived as different sounds

Question 28

What is Spectral Profile?

Answer 28

You have a bunch of sound frequencies and the more you have the more helpful this is. If you raise the level of just one of those frequencies, it will become more detectable because the brain is picking out anomalies

Question 29

What is Harmonicity?

Answer 29

All things being equal, if the sounds in a harmonic sequence or are harmonically related, they’ll be perceived as belonging together. If they are not in a harmonic sequence, they’ll be perceived as separate sounds

Question 30

What are Spatial Cues/Spatial Separation?

Answer 30

Sounds in similar locations are perceived to belong together.
2 sounds with with very similar binaural signatures will be perceived as belonging together

Question 31

What is Temporal Separation?

Answer 31

2 sounds that happen at the same time will be perceived as belonging together. Sounds happening at different times will be perceived as different

Question 32

What are Temporal Onsets/Offsets?

Answer 32

If 2 sounds start or end at the same time, they will be perceived as belonging together.

Question 33

What is Temporal Modulation?

Answer 33

2 sounds that change (frequency, amplitude, etc) over time in the same way are perceived to belong together.

Question 34

What are the 7 grouping principles?

Answer 34

1.) Spectral Separation
2.) Spectral Profile
3.) Harmonicity
4.) Spatial Separation
5.) Temporal Separation
6.) Temporal Onsets/Offsets
7.) Temporal Modulation

Question 35

How do movie theaters use grouping principles?

Answer 35

They use temporal onsets and offsets to match audio reaching the viewers with what they see on the screen, since there is a delay in sound reaching the viewer after the image. There is a small 200ms window where the amount of time can be imperfect, but they match together because the brain performs closure of auditory and visual cues in that time window.

Question 36

What is the McGurk Effect?

Answer 36

You perceive a sound that is neither visually nor auditorily represented because of multimodal perception

Question 37

What is an example of the McGurk Effect?

Answer 37

You are visually presented with [g] but auditorily presented with [b], but you perceive the sound [d]. You perceive [d] because it is alveolar, which is the average voiced plosive between bilabial [b] and velar [g].

Question 38

How do we localize sound in distance?

Answer 38

1.) Inverse Square Law
2.) Head Shadow