1.3 Auditory System

Question 1

Auditory stimulus

Answer 1

sound waves (sine waves, concentric)

Question 2

What is sound

Answer 2

auditory stimulus caused by displacement of elastic medium (compression and rarefaction of air molecules)

Question 3

Frequency

Answer 3

rate of cycles/wavelength (measured in Hz)

Question 4

Pitch

Answer 4

psychological dimension of frequency

Question 5

Human Frequency Range

Answer 5

20Hz to 20,000 Hz

Question 6

Lowest absolute threshold of humans

Answer 6

2000 Hz to 5000 Hz

Question 7

Difference threshold of humans best in…

Answer 7

500 Hz - 2000 Hz

Question 8

Amplitude

Answer 8

compression of sound wave (in dynes/cm^2)

Question 9

loudness

Answer 9

psychological dimension of amplitude

Question 10

Sound Pressure Level

Answer 10

Logarithmic, scale of sound pressure relative to threshold pressure, dB

Question 11

Phase Angle

Answer 11

Position of pressure change as it moves through cycle (where in sine wave) used in sound localization

Question 12

Complex Tones

Answer 12

Sounds made of multiple simple tones

Question 13

Fourier Analysis

Answer 13

decomposition of complex tones into its parts

Question 14

Sound Quality

Answer 14

intensity and frequency of sound

Question 15

Fundamental frequency

Answer 15

lowest frequency in complex tone

Question 16

Harmonics

Answer 16

all other frequencies in complex tone

Question 17

Timbre

Answer 17

psychological aspect of sound quality

Question 18

Outer Ear

Answer 18

Pinna, Auditory Canal, Eardrum

Question 19

Pinna

Answer 19

Outer ear, amplification and sound localization

Question 20

Auditory Canal

Answer 20

Where sound is compressed (ear wax = cerumen)

Question 21

Eardrum / Tympanic Membrane

Answer 21

vibrates in response to sound (most important part of ear)

Question 22

Middle Ear

Answer 22

Ossicles and Eustachian Tubes

Question 23

ossicles

Answer 23

malleus (hammer) incus (anvil) and stapes (stirrup)

Question 24

impedance mismatch

Answer 24

resistance due to change in medium from air to liquid (outer to middle ear). taken care of by ossicles

Question 25

Eustachian Tubes

Answer 25

in throat, equalized pressure in auditory system

Question 26

Inner Ear

Answer 26

Semicircular canal and cochlea

Question 27

outside cochlea

Answer 27

oval window and round window

Question 28

oval window

Answer 28

where sound arrives

Question 29

round window

Answer 29

where sound vibration dissipates

Question 30

inside cochlea canals

Answer 30

vestibular canal, middle canal, tympanic canal

Question 31

helicotrema

Answer 31

where vestibular and tympanic canal meet

Question 32

inside cochlea membranes

Answer 32

reissners membrane, tectorial membrane, basilar membrane

Question 33

Basilar membrane

Answer 33

traveling wave, travels on hairs on membrane

Question 34

organ of corti

Answer 34

includes inner and outer hair cells and is where transduction occurs (is tonotropically organized)

Question 35

Loudness and transduction

Answer 35

membrane vibrates more for loud sounds therefore we have more neural activity
Amount of neural activity = code for sound amplitude

Question 36

Pitch and Transduction

Answer 36

Place Principle and Volley Principle

Question 37

tonotropic organization

Answer 37

middle of cochlea = lower freq. base of cochloea = higher freq.

Question 38

Auditory Nerve

Answer 38

neural impulses leave cochlea and travel along this. each neuron is specific to particular frequency (tonoponic organization)

Question 39

Auditory Tuning Curve

Answer 39

relation between frequency of an auditory stimular and response of specific neuron

Question 40

WHERE relay

Answer 40

Inferior colliculus (sound localization)

Question 41

WHAT relay

Answer 41

medial geniculate nucleus (sound identification)

Question 42

Masking

Answer 42

how we determine what is background noise and what is foreground noise
uses: frequency and intensity
best masker has lower frequency than target noise