Sound Characteristics

Question 1

Audition

Answer 1

The biological process by which our ears process sound waves
- Humans with normal hearing can easily detect the source, direction, and complex combinations of sound like voices and music

Question 2

sound waves

Answer 2

• vibrations of molecules that travel through the air
• created by vibrating objects, and move much more slowly than light
• waves are characterized by their amplitude, wavelength, and purity

Question 3

Wavelength

Answer 3

• the frequency, measured in cycles per second, and affects the pitch (high or low)

Question 4

Amplitude

Answer 4

affects the loudness or intensity based on how much pressure is being forced through the air

Question 5

decibels

Answer 5

• the intensity of sound is measured using a scale of decibels
• the absolute threshold for sound is 0 dB, while noise above 120 db can cause damage to one’s hearing
• 150 db can cause the eardrum to rupture

Question 6

The Outer Ear

Answer 6

• called the pinna, catches sound waves

Question 7

pinna

Answer 7

directs sound waves through the ear canal, or auditory canal to the eardrum, or tympanic membrane

Question 8

The Middle Ear

Answer 8

• Sound waves then vibrate tiny malleus (hammer), incus (anvil), and stapes (stirrup)
• These bones transmit their vibrations to the cochlea, whose inner surface (basilar membrane) resonates to different sounds in different locations

Question 9

cochlea

Answer 9

a snail-shaped tube with fluid inside that is jostled with vibrations from the middle ear, bending the hairs that line its surface

Question 10

organ of corti

Answer 10

in the cochlea contains the hairs that convert the mechanical energy into electrical

Question 12

the inner ear

Answer 12

the movement of the hairs is transmitted as messages along the auditory nerve to the auditory cortex in the temporal lobe

Question 13

sensorineural hearing loss

Answer 13

there is damage to the inner ear, often to the cochlea

Question 14

Conductive hearing loss

Answer 14

sounds cannot get through the outer and middle ear

Question 15

Cochlear implants

Answer 15

help provide a sense of sound to a person who is deaf or hard of hearing

Question 16

how the cochlear implants work

Answer 16

cochlear implants electronic signals to stimulate the cochlea’s nerves to get the message to the brain

Question 17

Hermann von Helmholtz’s place theory

Answer 17

• higher and lower tones excite specific areas of the cochlea’s basilar membrane
• as sound waves enter the cochlea, higher pitched sounds displace the fluid in the inner ear
• high frequencies produce large vibrations along the beginning of the cochlea’s membrane, while low pitches vibrate the whole structure

Question 18

frequency theory

Answer 18

• suggests that as a pitch rises, the entire basilar membrane vibrates at that frequency
• the brain reads the pitch by monitoring the frequency of neural impulses as they travel the auditory nerve

Question 19

volley principle

Answer 19

suggests neural cells can fire alternately, allowing those that just fired to reset

Question 20

Locating sound

Answer 20

• your ears rely on volume and timing to determine where a sound is coming from
• the louder the sound, the closer it is
• the timing of when each ear receives the sound is also important

Question 21

Locating Sound

Answer 21

• the ear closer to the origin receives the sound first, with a slightly stronger signal
• the brain accurately locate sounds, unless they are directly in front, behind, or above us

Question 22

Signal detection theory

Answer 22

detection of a stimulus depends on the intensity of the stimulus and the physical and psychological state of the individual