Binaural Hearing Flashcards
What are the 3 dimensions you can localize sound in?
1.) Azimuth
2.) Elevation
3.) Distance
What are the 2 categories of sound localization cues in azimuth?
1.) Time/Phase
2.) Intensity/Level
What are interaural cues?
Locating the source of a sound by comparing the distance in arrival time of a sound between 2 ears
What is range of sound where people have trouble hearing speech in noise?
1000-2000Hz
If you remove high frequency information from the HRTF, what dimension can you not localize sound in?
Elevation
How can atmospheric absorption affect sound?
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
How does a response depend on how you ask a question about judging distance?
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
What is the minimum audible angle?
The smallest detectable difference in the direction of two sound sources that a person can reliably distinguish
How is sound affected in an anechoic room?
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.
What is the precedence effect?
An acoustic signal arriving first at one ear masks/suppresses the ability to hear any other signals from the other ear
What is Masking Level Difference?
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
Who discovered Masking Level Difference?
Ira Hirsch in the 1940s
What is the point of Auditory Aided Visual Search?
The ears are set up to be really good at localizing stimuli 4x faster than just using your eyes to location something.
What is lateralization?
Our ability to study localization/lateralize sound using headphones
What is a unique binaural signature?
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.
How do we utilize the Cocktail Party Effect?
We locate a person’s unique binaural signature to listen to one person in particular. This is about targets in noise.
How much amplification does the HRTF provide?
20dB
How do we externalize sound?
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.
What is extended high frequency hearing?
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
What are the 3 types of listening?
1.) Monotic
2.) Diotic
3.) Dichotic
Why would we use dichotic listening?
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.
What is the “right ear advantage”?
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.
How do we know what sounds belong together and what should be separated out?
We use unique binaural signatures and grouping principles to sort out what belongs together
What are grouping principles?
The perceptual rules that govern how we organize auditory stimuli into coherent wholes, based on spectral/frequency cues, spatial cues, and temporal cues
What are the 3 spectral/frequency cues in grouping principles?
1.) Spectral Separation
2.) Spectral Profile
3.) Harmonicity
What are the 3 Temporal cues in grouping principles?
1.) Temporal Separation
2.) Temporal Onsets/Offsets
3.) Temporal Modulation
What is Spectral Separation?
2 sounds that are similar in frequency will be perceived as belonging together. Sounds with different frequencies will be perceived as different sounds
What is Spectral Profile?
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
What is Harmonicity?
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
What are Spatial Cues/Spatial Separation?
Sounds in similar locations are perceived to belong together.
2 sounds with with very similar binaural signatures will be perceived as belonging together
What is Temporal Separation?
2 sounds that happen at the same time will be perceived as belonging together. Sounds happening at different times will be perceived as different
What are Temporal Onsets/Offsets?
If 2 sounds start or end at the same time, they will be perceived as belonging together.
What is Temporal Modulation?
2 sounds that change (frequency, amplitude, etc) over time in the same way are perceived to belong together.
What are the 7 grouping principles?
1.) Spectral Separation
2.) Spectral Profile
3.) Harmonicity
4.) Spatial Separation
5.) Temporal Separation
6.) Temporal Onsets/Offsets
7.) Temporal Modulation
How do movie theaters use grouping principles?
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.
What is the McGurk Effect?
You perceive a sound that is neither visually nor auditorily represented because of multimodal perception
What is an example of the McGurk Effect?
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].
How do we localize sound in distance?
1.) Inverse Square Law
2.) Head Shadow
