Auditory Sensation & Perception (8) Flashcards

1
Q

What makes a sound

A

When the movements or vibrations of an object cause pressure changes in the air, water or any other medium that surrounds the vibrating object

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2
Q

Tuning fork

A

Its vibrations produce a single pure tone by causing a SINUSOIDAL change in air pressure

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3
Q

Wavelength

A

Distance between 2 peaks

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4
Q

Amplitude

A

Distance from baseline to top of peak

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5
Q

Rarefaction

A

(Low pressure) particles far away from each other (opposite of compression)

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6
Q

Concentric

A

Changes in air pressure spread away from the tuning fork in all directions

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7
Q

Frequency = **

A

1/wavelength

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8
Q

What does frequency determine *

A

The perceived pitch

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9
Q

What is frequency measured in

A

Hertz

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10
Q

Amplitude determines.. *

A

The loudness of a tone

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11
Q

Amplitude is measured in. **

A

Decibels

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12
Q

Number of dB (decibels) equation ***

A

Number of dB = 20 x LOG (P/P°)

P is the sound pressure of the stimulus
P0 is a standard reference sound pressure

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13
Q

Why is the dB scale useful?

A
  1. It compresses the range of numbers we need to handle
  2. Relates well to our perception of loudness
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14
Q

How can we tell a piano from a guitar *

A

Overtones

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15
Q

What are overtones ***

A

The unique components of their complex sound waves whose frequencies are multiples of the fundamental frequencies of each tone

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16
Q

Outer ear consists of..

A

Pinna, auditory canal

17
Q

Pinna

A

Helps with sound location

18
Q

Auditory canal

A

Protects the tympanic membrane (ear drum) at the end of the canal

19
Q

The middle ear consists of.. *

A

Malleus (hammer), incus (anvil), stapes (stirrup)

20
Q

Malleus (hammer)

A

Moves due to the vibration of the tympanic membrane (ear drum)

21
Q

Incus (anvil)

A

Transmits vibrations of the malleus

22
Q

Stapes (stirrup) *

A

Transits vibrations of the incus to the inner ear via the oval window of the cochlea

23
Q

Outer and middle ear is filled with..

A

Air

24
Q

Inner ear is filled with..*

A

Fluid - that is much denser than air

(Pressure changes transmit poorly in this)

25
Q

Function of ossicles

A

Act to amplify the vibration for better transmission to the fluid

26
Q

What do middle ear muscles do?

A

Protect the cochlea from loud (amplified) noises by changing the strength of coupling between the 3 ossicles

27
Q

Basilar membrane (inner ear)..

A

Vibrates with high frequency while the lower, wider parts are softer and respond to lower frequencies

28
Q

Structures in the cochlea

A

The basilar membrane and the organ of Corti that contain the outer and inner hair cells and the tectorial membrane

29
Q

? What does the organ of corti consist of

A

Cilia + outer hair cells

30
Q

How does transduction by hair cells occur **

A

Movement of bundle of cilia in different directions causes either increase/ decrease in the firing rate of an auditory neuron

31
Q

What allows us to perceive a large range of frequencies? **

A

The tonotopic organisation of the basilar membrane - where the vibration is tells our brain what sound frequency is (place coding?)

High and middle frequencies are at different places on the basilar membrane

32
Q

High and middle frequencies on the basilar membrane

A

Place coding

33
Q

Low frequencies on the basilar membrane

A

Rate coding - follows the stimulus vibrations and the rate of firing of auditory neurons (this changes with the frequency of vibration)

Temporal coding

34
Q

(Localisation of sound) AZIMUTH coordinates

A

Position left to right

35
Q

(Auditory localisation) ELEVATION coordinates

A

Position up and down

36
Q

Distance coordinates

A

Position from observer

37
Q

Azimuth differences

A

Intensity - our head casts a shadow
Time of onset - differences in time of arrival can be coded - when distance to the ear is the same, there is no difference
Phase - ear drums will be pushed/ pulled at different rates - high frequency will be pushed in, low frequency will be pushed out (distance between ear drums)

38
Q

Moncaural cue for sound location **

A

The specific shape of our Pinna and head affect the intensities of different frequencies in a different way

Measured - small microphones in ears and comparing the intensities of frequencies with those at the sound source (spectral cue)

39
Q

Vestibular system

A

The sense of balance - a closely related sensory organ that uses hair cells