hearing Flashcards
what is sound
alternating waveforms consisting of compression and refraction of air molecules
what is a sound wave
sound varies depending in how dense the air is
what 3 things can you use to define sound
wavelength, velocity and frequency
what is pitch discrimination
a concept in which the ears and the brain disassociate different frequencies to hear sounds and not jut one noise
what is the equation for wavelength
wavelength = velocity /frequency
what is wavelength
the distance between each trough
what is wavelength unit
lander
what is frequency aka ….
pitch
what is the sound amplitude ratio
intensity in decibels = 10log 10 intensity of unknown / intensity of standard
what is the amplitude of a sound
aka decibel
what is the mean threshold of hearing
10^-12 Wm^-2
how do you find out the intensity in decibels
multiply by log base 10
what is the standard
is the sound in which u can first hear- low unit (watts per square meter )
range of human hearing will differ t or f
t
what is range of frequency for human hearing
20 -20000hz/ 20khz
what is the threshold frequency?
20hz
what frequency is the rumbling with your fingers in your ears
25hz
music is what frequency
44khz- so you can hear it clearly at 20hz
140 decibels can cause what
damage - even if short
what decreases as you get older
auditory hair cells
lack of hair cells impacts what
higher frequencies
what do we call hearing loss
Prebycusis
what are the 3 basic parts of the ear
inner, outer and middle
ears can what sound
discriminate
what is the bone above the outer ear
temporal
where is the ear drum located
outer canal
which part does the work in the ear
inner - needs movement to move
the sound goes through the tunnel, strikes the air drum which strikes the bones in the middle ear which then
bones strike the cochlea and the sound moves through fluid
why wouldnt not having the middle ossical bones work
due to the fluid - it allows movement back and forwards - if rigid it wouldnt move - allowing flexibility -
what is the membrane inside the inner ear
basilar membrane
what are the 3 bones in the ears
malleus, incus, stapes
the middle ear acts as a
lever
the middle ear lever converts high amplitude and low force motion into…
low amplitude and high force motion at the oval window
what is impedance matching mechanism
the process of matching the impedance within the middle ear
what would happen if the bone was connected directly to the oval window
The sound would stop dead due to high amplitudes moving with temperature
which bone is connected to the tympanic membrane
malleus
stapes - smallest bone in the body connected to
the oval window
what is the stapedius reflex
the contract of the muscles - tensor tympani, stapedius - pull stapes away from the oval window
the stapedius reflex decreases what
transmission of energy to cochlea
the strapedius reflex occurs in response to what
loud noise
what is the main job of the strapedius reflex
help prevent ear damage
what are the 3 chambers in the inner ear
3 scaley
vestibuli, media (middle) tympani
how do you transduce that motion into a neural signal
through the organ of corti
where is the organ of corti
in the media channel
what nerve is connected to organ of corti
auditory nerve
what are the 2 hair cells in the organ of corti
inner hair sensation and outer hair motors
what are the 2 hair cells in the organ of corti connected to
the tectorial membrane
what do vestibular hair cells detect
physical motion
auditory hair detect what
physical motion
what causes the basilar membrane to move
the fluid moving in the vestibular and tympani
what activates the hair cells
the movement from the cochlea in the vestibule and tympani movement which will effect the tectorial membrane and the hair cells
what are the two hair cells inhibition
stereocilia and kinocilium
which hair cell inhibit of transmission release
stereocilia
which hair cell activates transmitter release
kinocilium
what is pitch place theory
how does the basilar membrane oscillation vary- pitch place theory
due to the size of the channel - it gets smaller the length gets longer- due to mechanics - high frequency at entrance by oval
pitch place theory is
pitch / freqency varies along different places
what is Fourier analyser
math technique - breaks down repetitive wave form into a series of waves with amplitudes and phases
the ear acts as a what
Fourier analyser - it decomposes time based sound signals into frequency (decreasing hz)
how does the ear fourier
the membrane breaks up the sound and decreases the frequency as it goes down the further distance
active undampening / positive feedback outer hair cells
the sound moving through the cell and reverse it back
why is discriminating noise important for humans
because we communicate through speech
the loudness of fewquency can be adjusted to get what
the same effect - through contours
what is an audio gram
A graph that shows hearing loss and a record produced by auditory- can see peoples threshold of hearing
hearing loss can be caused by what
loud noises, long term loud nosie or one big burst depedning on frequency and loudness
auditory pathway
what is the main part of the brain for hearing
primary auditory cortex
what is the brain primary auditory cortex connected too
cochlea
what is the superior olive
brainstem
latencies on eeg can indicate what
how far the cochlea is
where is the auditory cortex
in the temporal
what 2 areas of speech can we identify?
Brocas speech and Wernickes speech-in frontal lobe
what role do werkines and broca -
understanding (W) and generation speech ( b)
stroke can impact the speech why
damage to b r w can impacting speaking
what does broca impact
making speech
what does wernicke impact
speech interpretation
where are the b and w for speech
cerebral cortex
range is ..
distance
what is bearing
azimuth and elevation
up or down , left or right - or angle of direction
cocktail party effect is important why
to differentiate background and frontal noise and speech
what cues help when listening
lip reading, visual, reading- sound localisation is key tho
distances impact sound localisation because of ..
frequency changes
judging distance what things will effect this
frequency , echos, expectation, timbre/ bass travels best, silibants worst, reverb
judging direction is what 3 things
intra aural,- timing n
intra aural volume and specttral colouring - by head and pinna
Intra-aural volume distances
ILD
better for what frequency sounds
high
you head does what to sound
attenuating
far away speech is what
more bassey
sibilants are what
attenuated
timing differences
distance effects sound in terms of what example
closer the source to which- inter aural timing difference- ear is where it will reach first
jeffress theory - superior olive in brainstem where sound will…
arrive first
the neurons in superior olive act as a
coincidence detector
what is a phase difference
when the peak of wave hits the ear at a different time as the trough hits the other ear due to the position of how the waves hit the head- continuous sound
how does head size matter
big head = large distance for wave length to hit both ears
how does animals use timing or loudness differently
elephant - distant bc of bigger head and smaller loudness relies on distance for predators
cone of confusion is what
sound
effects you from the front and back as they strike ears at the same time rather left to right more commonly but nt impossible for left to right - physics of the head
bobbing head shows what
trying to use cone of confusion
big ears can help with sound waves how
cone shape pick up more sound- active pinna to funnel noise in the ear
what is binural microphone
asmr double micorphones
sound with narrow bands of frequency and gradual onsets are hard to..
localize
auditory reaction times average is what time
140-160ms
visual reaction is slower by how many average
20-40ms - 160-200ms
sound takes …. per meter
3ms
higher frequency means a faster reaction t or f
f
startle reponse is what
flexion of shoulder, protective - response to loud noise
startle may impact reaction time and decrease reaction time t or f
t - moot point
