Sound Location & Binaural Hearing Flashcards
Spatial dimensions:
The source of sound can be localized in 3 dimensions:
Sound has ___ spatial dimensions
L -R (horizontal)
Up-down (vertical)
Near-far (range)
NO
We localize sound using cues such as:
Time of arrival of sound @ ear
Intensity level
Frequency cues
Interaural time difference (ITD)
The difference in time of arrival @ each ear
If Called from the left, voice will reach ____ ear first and you will turn to the ______.
Left
Left
Due to characteristics of sinusoids, if 2 sounds arrive at different times their ______ will be different at each ear
Phase
Interaural intensity difference (IID)
Sound reaching the R ear first sounds ______ at right ear than left ear because of the ________.
Louder
Inverse square law
Frequency differences will cause differences in ________ as well.
Higher frequencies blocked by ______________ .
Intensity
Size and shape of person’s head
Low frequencies will _____ around head more easily because low frequencies travel _______ ________, high frequencies can’t.
Bend
Around corners
Higher frequencies ______ intensity trying to get around the head. Therefore, easier for listeners to determine location of low and high frequency sounds.
Lose
Hard to determine location of _____ frequency sounds at approx. ________Hz
Mid
2000
Duplex theory of Localization:
2 cues to determine where sound is coming from:
The interaural TIME difference (ITD)
The interaural intensity difference (IID)
ITD =
Interaural time difference
Which ear receives the sound first?
Provides info for low frequencies below 1666Hz
IID =
Interaural intensity difference
Which ear gets the louder signal?
Provides info about higher frequencies
The “cone of confusion”
Sounds which come from directly in front or behind have NO ITD or IID
Have to make small adjustments to head to localize
Localization of the vertical plane
Components of the _______ _____ also contribute to localization
External ear
Ears act as :
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
Binaural effect
Binaural summation threshold:
Slight improvement in hearing threshold (about 3dB on average with 2 ears rather than just 1
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 :
Second
Dominated
Echo suppression
Speech benefits of the precedence effect:
Suppresses the effects of reflections that might interfere with perception of a sound
Reflections that arrive beyond the time when the precedence effect oxides results in the ______ .
2 types :
Making of a signal
Late and early reverberation
Lateralization
When you test user headphones you don’t have the advantage of the ________ to enhance the signal.
Outer ear
Headphone tests
Can control time of arrival to each ear, phase and intensity independently
Listener usually perceives the tone as an image in their head
Localization occurs __________ , while Lateralization occurs __________.
Environment
Headphones
Lateralization (headphones)
If difference between 2 stimuli is great, the listener will hear 2 diff. Sound and the __________ won’t _______.
Image
Fuse
