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30 Cards in this Set
- Front
- Back
what is the perceptual definition of sound and physical definition? |
perceptual: sound is the exp we have when we hear physical: sound is pressure changes in the air or other medium caused by the vibration of an object |
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what is amplitude and what is frequency |
amplitude is the variation in the air pressure(diff between peak n trough), perception of loudness frequency is number of cycles per sec(1 Hertz = 1 cycle/s),pitch |
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what are the 3 ear bones starting from the one most outside? purpose? |
Ossicles in middle ear:malleus(hammer), incus(anvil) and stapes(stirrup) amplify the vibrations of the tympanic membrane n transmit them to the inner ear at the oval window |
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what are the parts that make the outer ear? |
pinnae( visible external parts of ear) auditory canal (~3cm tube-like structure, protects middle ear) tympanic membrane (eardrum) |
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how does the tympanic membrane(ear drum) work? |
-cone shaped membrane separating the outer n middle ear -sound waves induce a diff in pressure either side of tympanic membrane, causing it to vibrate -larger amplitude sounds result in larger -higher frequency sounds result in faster vibrations |
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how is the structure of the inner ear like? |
contains the cochlea, a snail-like liquid-filled organ vibration of the oval window displaces fluid in the cochlea, resulting in a change in pressure which propagates up n down the spiral structure |
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the cochlea consists of 3 parallel canals what are they? |
vestibular middle tympanic |
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how does the auditory transduction work? |
auditory transduction is triggered by motion of the basilar membrane, organ of corti translates the motion of the basilar membrane into neural signals, a voltage is generated when specialized hair cells contained within the organ of corti r bent, producing impulses in auditory nerve cells sent to brain. |
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what is the rate code |
sound amplitude is coded in the firing rate of auditory nerve fibers |
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how does the auditory nerve fibers allow us to discriminate loudness? |
responses increase with increasing sound intensity some fibers have spontaneous rates and saturate rapidly, others have low spontaneous rate n saturate slowly |
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amplitude n loudness is not directly proportional, how do u x2 loudness of the sound? |
for sound to be x2 loud the amplitude needs to be increase by approx 3.16(10dB) |
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in regards to pitch there is a place code. where do the low n high go? |
sounds frequencies cause vibration in specific areas along the basilar membrane. high frequencies near base, low frequencies near apex |
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what is phase locking? |
where the auditory system keep track of the number of times of occurrence of the ongoing amplitude fluctuations in sounds auditory nerve responses are synchronised to changes in pressure(occur up to 4,000Hz) |
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why does the same note sound diff when played on diff instruments? |
pitch usually determined by fundamental frequency of the sound perceived sound quality(ie.timbre) is related to the number, frequency ratios n relative amplitudes of the harmonics |
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the fundamental frequency determines the perceived pitch so what happens when we remove it? |
there is the missing fundamental illusion perceived pitch is consistent with the missing fundamental frequency, suggests that pitch isn't simply determined n cochlea-the brain infers the missing fundamental from the harmonics |
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what is the difference between comparing location information in vision and audition? |
relative location of objects is contained within the retinal image, place activated by a sound on the cochlea does not indicate location |
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how to we localise sound? |
binaural cues: comparison of signals in the left n right ear location of sound in azimuth(ITDs and ILDs) monaural cues: works with one ear, localize the elevation(up-down plane) n distance of sound, filter properties of pinna, intensity n reverberation |
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what is interaural time diff (ITDs) |
the relative time at which a sound arrives at two ears depends on its location in azimuth, depends on speed of sound 330ms, bigger head give bigger ITDs (max ~0.06ms) |
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what are ILDs and what is it caused by? |
interaural level differences, relative sound pressure reaching the 2 ears depends on the location of the source in azimuth. reduction in sound lvl occurs for the far ear, due to acoustic shadow. reduction occurs for high frequency not low frequnecy |
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explain the physiology of binaural processing |
binaural localisation cues processed by diff types of neurons, located in diff parts of superior olivary complex(superior olive) -lateral superior olive(LSO) contains neurons sensitive to ILDs -medial superior olive(MSO) contains neurons sensitive to ITDs |
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what are the strength n weaknesses of binaural cues? |
ITDs n ILDs provide complementary information about azimuth location, ITDs work well for low frequency sounds, ILDs provide information about high frequency sounds ambigious info about elevation n distance |
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what is cone of confusion? |
set of points from which a sound source will produce identical ITDs and ILDs |
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for monaural localisation cues for elevation, what are the filter properties of the pinnae? |
sounds hits the pinnae the relative intensity of diff frequencies sound waves changes, changes with sound source elevation |
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what are 2 monaural localisation cues that tells us the distance? |
relative intnesity(sound intensity decrease with distance) reverberation (the way sound reflects off objects provides cue to distance), multiple reflections combine to produce a persistence of sound called reverberation. |
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what is the precedence effect? |
due to reverberation there is multiple sounds reaching the listener from multiple directions we can tell the location because similar sounds are arriving in quick successions from diff location according to direction of first sound provided delay is short (<10-20ms) single sound perceived |
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what is spectral grouping? |
frequency components of a sound are more likely to be grouped into a single sound likely to be caused by same sound producing event. common frequency change(analogous to principle of common fate), frequency that change together tend to group together |
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what is sequential grouping? |
auditory stream segregation, organising sounds over time into separate perceptual events |
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what are 4 ways sequential grouping can occur? |
similarity of pitch temporal proximity(sounds occurring in rapid progression tend to be produced by same source) similarity of timre continuity(sounds stay constant n perceived continuous when interrupted by noise) |
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what is phonemic restoration? |
effect of sequential grouping for continuity is not restricted to tones but also occurs with speech |
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what is free recall? |
participants are presented with a given number of stimuli, and ltr they are asked to rmbr the stimuli or asked to rmbr smtg they alrdy have in their memory(open essay questions) |