Chapter 12 Flashcards
Azimuth Coordinates
Position Left to right(binaural cues)
Elevation Coordinates
Position up and down (monaural cues)
Distance Coordinates
Position from observer
Where can people localize sound from best?
In front of us
Where can people localize sound from the worst?
Behind us and to the sides
Why must location be calculated?
Because location cues are not contained in the receptor cells like it is in the vision
Binaural cues
location cues based on the comparison of the signals received by the left and right ears
Interaural time difference (ITD)
difference between the times sounds reach the two ears, not as effective with high frequency sounds
Interaural level difference (ILD)
Difference in sound pressure level reaching the two ear, low frequency waves aren’t as effective. Best for high frequency. Head casts an acoustic shadow
ITD is best for low frequency, why?
FINISH THIS
ILD is best for high frequency, why?
FINISH THIS
Monaural cues
uses information from one ear. Spectral cue.
brain learns where a sound is coming from by….
The way sound reflects off the pinna.
After the information leaves the cochlea it goes to what?
Superior Olivary Nucleus Inferior Colluculus Medial Geniculate nucleus
then into Auditory receiving area (A1)
Heirarchical processing
neural signals travel through the core, then belt, followed by the parabelt area
Simple sounds cause activation where?
in the core area
Jeffress Model
narrowly tuned ITD neurons (one to one coding). Coincidence detectors fire only when sounds is in front (birds)
Broadly-tuned ITD neurons
Found when testing mammals. distributed coding was found.
Ventral stream
recognition of sound
Dorsal stream
location of sound
Direct sound
Sound that comes straight from the source to the listener’s ears
Indirect sound
reflected sound
when outside sound is most…..
direct
Reverberation time
the time it takes sound to decrease by 1/1000th of its original pressure.
