Perception 4 Flashcards
Perception of sound
Experience we have when we hear
Physical sound
Pressure changes in air or medium caused by vibration of an object
Pure tone occurs when
Change in air/medium caused by vibration of an object
Characteristics of sound
Amplitude, frequency, sound waves
Amplitude
Size of variation in air pressure effects loudness
Frequency
Number of cycles per second, related to pitch
Sound waves
Sine waves combining
Natural sounds are made up of
Fundamental frequency
Fundamental frequency
Superimposed by additional waveforms with higher frequencies
Pitch
Sound frequencies cause vibration in specific area along basilar membrane
Low frequency
Is near apex
High frequency
Near base
Frequency is signaled
When auditory nerves respond
Pitch is determined
By fundamental frequency of sound
Pitch is determined
By fundamental frequency of sound
Phase locking
Auditory nerve responses synchronize to change in pressure up to frequencies of about 400 Hz
Timbre
Dictated by the number, frequency ratio, relative amplitudes of the harmonics
The missing fundamental illusion
We perceive a pitch consistent with the missing fundamental frequency
The brain infers the missing fundamental
From the harmonies
Loudness
Amplitude of sound waves
Sound is measured in
dB
Change of 20dB
Same as 10x increase in amplitude
The range in amplitude we encounter is ____
Large
Sound amplitude is coded in
The firing rate of the auditory nerve
We have poor sensitivity for extremely ____ and ____ frequencies
Low and high
Parts of ear
Outer ear, middle ear, inner ear
Parts of outer ear
Pinnae, auditory canal, eardrum
Pinnae
Visible external part of ear
Auditory canal
About 3 cm tube that protects ear
Eardrum
Aka tympanic membrane, cone shaped membrane separating middle and outer ear
The higher the frequency, the
Faster vibrating
The larger amplitude, the
Larger vibration
Parts of middle ear
Malleus, incus, stapes
The malleus, incus, and stapes are the
3 smallest bones in the human body
The three bones in the middle ear amplify
Vibrations of eardrum and transmit them to inner ear at oval window
Inner ear contains the
Cochlea
Cochlea
Snail like liquid filled organ where fluid is displaced by oval window, which changes the pressure in the cochlea
The three parallel canals in the cochlea
Vestibular, middle, tympanic
Basilar membrane
Triggers auditory transduction and separates the middle and tympanic canals
The organ of corgi extends along
The surface of the basilar membrane
When hair cells in the organ of the corti are bent,
A voltage is generated
Because hair cells are extremely sensitive, so loud sounds
Cause hearing loss
Sound frequencies cause vibration
In specific areas along basilar membrane
Low frequency is
Near apex
High frequency is
Near base
