Auditory Sensation & Perception (8)

Question 1

What makes a sound

Answer 1

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

Question 2

Tuning fork

Answer 2

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

Question 3

Wavelength

Answer 3

Distance between 2 peaks

Question 4

Amplitude

Answer 4

Distance from baseline to top of peak

Question 5

Rarefaction

Answer 5

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

Question 6

Concentric

Answer 6

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

Question 7

Frequency = **

Answer 7

1/wavelength

Question 8

What does frequency determine *

Answer 8

The perceived pitch

Question 9

What is frequency measured in

Answer 9

Hertz

Question 10

Amplitude determines.. *

Answer 10

The loudness of a tone

Question 11

Amplitude is measured in. **

Answer 11

Decibels

Question 12

Number of dB (decibels) equation ***

Answer 12

Number of dB = 20 x LOG (P/P°)

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

Question 13

Why is the dB scale useful?

Answer 13

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

Question 14

How can we tell a piano from a guitar *

Answer 14

Overtones

Question 15

What are overtones ***

Answer 15

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

Question 16

Outer ear consists of..

Answer 16

Pinna, auditory canal

Question 17

Pinna

Answer 17

Helps with sound location

Question 18

Auditory canal

Answer 18

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

Question 19

The middle ear consists of.. *

Answer 19

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

Question 20

Malleus (hammer)

Answer 20

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

Question 21

Incus (anvil)

Answer 21

Transmits vibrations of the malleus

Question 22

Stapes (stirrup) *

Answer 22

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

Question 23

Outer and middle ear is filled with..

Answer 23

Air

Question 24

Inner ear is filled with..*

Answer 24

Fluid - that is much denser than air

(Pressure changes transmit poorly in this)

Question 25

Function of ossicles

Answer 25

Act to amplify the vibration for better transmission to the fluid

Question 26

What do middle ear muscles do?

Answer 26

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

Question 27

Basilar membrane (inner ear)..

Answer 27

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

Question 28

Structures in the cochlea

Answer 28

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

Question 29

? What does the organ of corti consist of

Answer 29

Cilia + outer hair cells

Question 30

How does transduction by hair cells occur **

Answer 30

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

Question 31

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

Answer 31

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

Question 32

High and middle frequencies on the basilar membrane

Answer 32

Place coding

Question 33

Low frequencies on the basilar membrane

Answer 33

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

Question 34

(Localisation of sound) AZIMUTH coordinates

Answer 34

Position left to right

Question 35

(Auditory localisation) ELEVATION coordinates

Answer 35

Position up and down

Question 36

Distance coordinates

Answer 36

Position from observer

Question 37

Azimuth differences

Answer 37

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)

Question 38

Moncaural cue for sound location **

Answer 38

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)

Question 39

Vestibular system

Answer 39

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