final exam new info Flashcards
1
Q
temporal processing
A
allows us to test the ability of the auditory system within the domain of time
-temporal resolution
-temporal ordering
2
Q
temporal resolution / temporal discrimination
A
shortest period of time over which the ear can discriminate between two signals
-tracking changes
3
Q
what’s another name for temporal discrimination
A
temporal resolution
4
Q
how to test temporal resolution
A
gap detection and TMTF
5
Q
what is gap detection
A
detecting the gap between two sounds
6
Q
how is temporal resolution assessed using a gap detection task
A
plays two sounds and over time shorted the silent gap between them
-important for speech perception
7
Q
TMTF
A
temporal modulation transfer function
-ability to detect amplitude modulation in a sound
8
Q
how is TMTF used to asses a modulated noise
A
good at detecting changs in amplitudes at low rates
-the higher the frequency, the greater depth is needed to hear the difference
9
Q
modulation rates vs. modulate depth
A
how many per a amount of time vs. the depth between peaks
10
Q
at what modulation rate is the auditory system able to detect changes in an amplitude modulated signal?
A
2-3 msec
11
Q
temporal ordering
A
the ability to process auditory stimuli in their order of occurrence
-process sound in the way we receive it
12
Q
temporal ordering is important for _______ perception
A
speech
13
Q
how is temporal ordering assessed?
A
present stimulus to patient in which they need to repeat in the order it was received
-words are varied by one letter (pit, pet, pot, pat)
14
Q
how does presentation duration affect absolute threshold
A
if presentation is too short, the threshold will be higher than the actual threshold
15
Q
temporal integration
A
ability of the auditory system to add up information over time up to a critical duration
16
Q
minimum presentation length of a pure tone to ensure valid testing
A
200 msec
17
Q
how does presentation duration affect loudness perception
A
over time, loudness appears not as loud
18
Q
loudness adaptation
A
when loudness perception diminishes over presentation time
-more prevalent near threshold
19
Q
pitch
A
perceptual attribute of sounds that allows them to make a melody and to be perceived on a scale from low to high
20
Q
place model for pitch perception
A
based on spectral representation
-frequency vs. amplitude
21
Q
temporal model for pitch perception
A
based on the waveform representation
22
Q
place code
A
based on place of maximal stimulation within the cochlea
-single tone is one point
-complex tone if the spacing of peaks
23
Q
temporal code
A
based on pattern of neural firing
-includes phase locking
-individual fibers will not fire at every spot but there will be a fire at every location
24
Q
phase locking
A
tendency of a neuron to fire at a particular phase
25
phase-locking applies up to __________ Hz
3000-5000
26
T/F : a doubling of frequency results in a doubling of pitch perception
false
27
T/F : pitch perception is affected by intensity
true
28
what role does pitch perception play in understanding speech in noise
supports auditory scene analysis
-helps within detecting what noise to follow based on the perceived pitch
-brain used pitch to follow various sounds
29
frequency selectivity
the ability to perceive separately multiple components of a complex sound
-ability to detect various parts of the sound
30
psychoacoustic masking
a listener's sensitivity for one sound is affected by the presence of another
-one sound in presence of another sound is adjusting the presence perception of it
-within cochlea
31
partial masking
sound is perceived as softer but still audible
32
masker
sound increasing threshold of other sound
-it is what is adjusting the other sound
33
test signal (probe signal or maskee)
sound being listened for
-sound being masked
34
amount of masking
the amount of dB in the threshold that is shifted
35
how to identify the amount of masking is presented with a graph showing threhsolds in quiet
the amount of threshold shift
36
tone-on-tone masking curves
look at the box and find the frequency you are trying to mask at the bottom line of all graphs (x-axis). trace that bottom frequency amount up to the masking line and if masking occurs, trace over to y-axis to find amount of masking.
37
3 factors that influence masking
intensity of the masker, relationship between the spectral characteristics of the masker and signal, and temporal characteristics of the masker
38
upward spread of masking
lower frequencies will mask the higher frequencies due to location on the basilar membrane
-lower frequencies are located near the apex and as they spread outward they will begin to mask the higher frequencies
39
why do we not see significant downward spread of masking
on the basilar membrane, higher frequencies are located near the base and therefore they will not be able to stretch to the higher frequencies to cause masking
40
fletcher's critical bandwidth experiment
questions of interest : how much of white noise actually contributes to the masking of a tone?
-how would you test this?
continue testing more and more bandwidth amounts until the threshold shifts and once it stops, that the point it not longer affects it
shifts up to a point until there is no longer the ability to mask
41
central masking
interaction in binaural auditory pathways
-masker presented to one ear can cause a threshold to shift for a signal at the other ear
-central auditory pathways
-different ears
42
temporal masking
masking may occur when the masker and test signal do overlap in time
-sequential
-neural pathway
-same ear
43
backward masking
tone followed by noise
44
forward masking
noise followed by tone
-can shift threshold if too close in time
45
cochlear dead regions
loss of IHC
-sounds at that frequency will not be converted to a neural signal
46
on frequency with cochlear dead regions
responds at the best frequency or CF
-takes place at point of maximum displacement
47
off frequency with cochlear dead regions
responds at a different spot then intended to respond
-takes place at a place other than the point of maximum displacement
48
how can masking a noise determine if a threshold reflects on or off frequency
-if masking interferes with threshold it was off frequency
-if masking did not interfere with threshold, you had on frequency
49
binaural fusion
separate signals from each ear are perceived as a single, fused auditory image
-both ears get sound, but you are only hearing one thing
50
binaural summation
how the auditory system adds together what it is receiving
-improvements of around 3 dB in detection, discrimination, and speech understanding when using both ears
51
imagine you have a patient with symmetrical hearing loss. they come to your office wearing one hearing aid because the second one is broken. they tell you that the overall volume is comfortable with one hearing aid in. you fix their other hearing aid and set it so both hearing aids have the same settings. will the set of hearing aids still be comfortable or will adjustments need to be made? (connect to binaural summation)
it would be too loud because it was fine with just one and when you add the second one, the system sums together the information so it would be at a higher level.
52
azimuth
horizontal plane
-0 degrees at face, 90 degrees at the right side, 180 degrees at the back
53
elevation
vertical or medial plane
-0 at face, 90 at the top of the head, 180 at the back of the head
54
sound localization
being able to detect where sound is coming from based on the sound arriving to a certain ear first
55
how does sound localization occur in a horizontal plane
interaural time differences and interaural level differences
56
interaural level differences (ILD's)
size of the difference between the two ears as they receive sound at a various starting point
-seen within high frequencies (above 1500 Hz)
-in comparison between each ear in regards to the loudness of the sound in dB
-at 0 azimuth, no ILD
-at 90 azimuth, biggest ILD will occur
57
interaural time differences (ITD's)
as the sound goes around the head, the WL is larger so it continues to move around and it is measuring the phase difference of the cycle at each ear
-low frequency cue (below 1500 Hz)
-at 0 azimuth, ITD is zero
-at 90 azimuth, it is greatest
58
how does monaural auditory system localize sound in vertical or medial plane
head related transfer function
59
head related transfer function (HRTF)
describes the spectral characteristic of sound as measured at the TM when sound source originates in 3D space
-difference based on elevation
-need a braodband signal or noise
60
binaural advantages for hearing in noise
reduces effects of noise
-better ear effect
-binaural squelch
-masking level difference
-echo suppression/precedence effect
61
signal to noise ratio
relationship between desired target (signal) and noise (anything that is not the target)
-SNR = signal level - noise level
62
better ear advantage
better SNR in ear closest to the signal
-up to 8 dB advantage
63
binaural squelch
performance improves due to including the second ear with poor SNR
-when you use better ear along with the other ear
-3 to 5 dB advantage
64
masking level difference
can reduce the effects of noise to enhance perception of signal
-diotic : same stimulus to both ears
-dichotic : different stimulus presented to each ear
65
resonance
one object vibrates at the same natural frequency of a second object forces that second object into vibrational motions
66
free vibration
force is applied one time and object oscillates at its natural frequency
67
forced vibration
object is forced to vibrate by a vibrating outside source
68
why does the range of hearing differ for different animal species based on ossicle size
due to the size of ossicles, we do not hear all frequencies the same
-the smaller the ossicles, the more high frequencies you will have
-smaller ossicles can vibrate faster
69
distortion
changes in sound
-not always bad or unwanted
70
frequency distorition
frequencies change as they go through a system
-the frequency is attenuated after passing through a system
71
transient distortion
how sound changes based on the presentation duration
-can result in spectral splatter
72
what is another name for transient distortion
temporal
73
amplitude distortion
distortion that occurs when the output is not a linear function of the input
-happens within nonlinear systems
74
harmonic distortion
refers to harmonics of the signal that are present in the output that were not present in the original stimulus
-results in amplitude distortion
75
intermodulaltion distortion
similar to harmonic distortion but with a complex periodic signal
-output spectrum is more complicated
76
what is the main difference between harmonic and intermodulation distortion
harmonic is one sound and intermodulation is multiple (complex) sounds
77
ramping (rise and fall time)
rise time : time to reach full amplitude
fall time : time to go from full amplitude to zero
78
what is the minimum time for rise AND fall times
20 msec
-for each
79
what is the minimum signal duration
200 msec
80
spectral splatter
result of transient distortion
-unwanted frequency components in a plot
-the little bump appearance next to the main signal
81
a shorter duration will result with a ______ splatter
broader
82
sound propagation
sequence of waves of pressure which travels through a medium
83
inverse square law
further from the source, more disburse the sound goes
-area is greater from the source, and if we measure at source and further from source the spot at the source will be 1/4 of the new spot
-applies for intensity
84
how to calculate sound intensity using the inverse square law
intensity / step from source squared
-ex. 3rd step would be intensity /3^2
85
how does a dB SPL value change with a doubling of distance from the source
for every doubling of distance, subtract 6 dB
86
transmission
when sound goes from one medium to another
-occurs when mass and elasticity of the medium are similar
87
reflection
when sound bounces off of an object
-inflection and reflected wave
88
inflection vs. reflected wave
original wave from source vs. the reflected wave
89
what occurs when a wave hits a convex surface? concave surface?
scatter with convex and gather with concave
90
diffraction
when sound is encountering an object or opening
-dependent on the size of opening and size of obstacle
91
what occurs if the size of an opening is small relative to the wavelength?
the sound will scatter as if the opening is a new source
92
what occurs if the size of an opening is large relative to the wavelength?
the sound will continue straight on through without scattering
93
what occurs if the size of the obstacle is small relative to the wavelength?
the sound waves will scatter around the object
94
what occurs if the size of the obstacle is large relative to the wavelength?
the object will cast a sound shadow
-the space behind obstacle remains untouched with sound
95
absorption
energy is dissipated within the material
-good absorbers : soft and rough surfaces
-poor absorbers : hard, dense, and smooth surfaces
96
sound field
a region within a medium where sound waves are moving around or are being propagated
-the area where sound is
97
near field
this is within one wavelength of the source
-remember, inverse square law will not hold here
98
far field
the field beyond the near field
-starting at the one wavelength point
99
free field
where sound wave travels without obstruction
-inverse square law can be used here
100
diffuse field
where there are reflections present
-cannot use inverse square law here
101
doppler effect
how the pitch changes according to the sound source movement
-as source moves closer, there will be a higher pitch (WL compressing)
-as source moves away, there will be a lower pitch (WL elongating)
102
what is a standing wave
wave that appears to stand still as a result of two sound waves in an enclosed area propagating in different directions
-areas of double frequency and zero frequency (as a result of being 180 out of phase or in phase)
103
why are standing waves of potential concern in audiology
calibration issues when the ear canal is involved, hearing aid measurements, and within sound field testing
104
if you increase the length of a tube, you _________ the resonant frequency
lower
105
if you decrease the length of a tube, you __________ the resonant frequency
increase
106
dB HL to dB SPL
add table value to HL for SPL
107
dB SPL to dB HL
subtract table value from SPL for HL
108
dB SL
sensation level
-difference between presentation and individual threshold
-SL = presentation - individual threshold
109
what is ANSI
american national standards institute
-standards organization for things such as calibration
110
boyle's law
pressure and volume are inversely proportional
-increase volume, pressure decreases
-decrease volume, pressure increases
111
why are RETSPL values different for different transducers
the amount of space between the transducer and the ear drum is different and because this volume is different (more you have, less pressure you have) you need a different volume
112
immittance
how well energy flows through a system
113
impedance
opposition to energy flow
114
admittance
ease of energy flow
115
3 components of impedance
stiffness reactance, mass reactance, and acoustic resistance
116
stiffness reactance
opposition to low frequencies
-large stiffness will have difficulty vibrating slowly
117
mass reactance
opposition to high frequencies
-large mass will have difficulty vibrating quickly
118
acoustic resistance
opposition of energy flow
-frequency independent
119
what happens with mass reactance and stiffness reactance at a systems natural frequency
these values are equal, so they cancel out
120
a narrowly tuned curve is ....
less resistant and an efficient generator of sound
121
a broadly tuned curve is .....
more resistant and an efficient transducer of sound
122
what would cause low frequency hearing loss
increase of stiffness
123
what could cause high frequency hearing loss
increase of mass
-such as an earplug in the ear canal
124
what is the perceptual quality of amplitude or intensity
loudness
125
what is the perceptual quality of frequency
pitch
126
what is the perceptual quality of time
duration
