PSY 131 midterm 2 Flashcards
Transient signals/ click stimulus/ spectral splatter
brief acoustical signal in which the sound level changes abruptly
Perceptual Beats
periodic change in overall loudness of a tone; occurs if change in f is less than 15-20 Hz
acoustic beats
periodic increase + decrease in amplitude caused by superposition of 2 sine waves of different frequencies
amplitude modulation
multiplication of two signals results in a change in temporal envelope
frequency modulation
addition of two signals does not change temporal envelope
sidebands
two frequency components
noise
random sequence of amplitude variations over time
low pass filter
passes all frequencies below cutoff
high pass filter
passes all frequencies above cutoff
bandpass
passes all frequencies between upper and lower cutoff
bandstop
attenuates all frequencies between upper and lower cutoff
linear system
output of the system is linear function to the input
nonlinear system
nonlinear relationship between input and output
can introduce new frequency components
difference tone
type of intermodulation distortion (equal to the change of f of two frequency components)
intermodular distortion
results from nonlinear system: the interaction of two or more frequency components
compression
reduce range of sound intensities in the output
Driver
catalyst that causes vibration of sound source (hand, hammer, etc)
generator
the medium in or on which a standing wave of vibration is created and maintained (string, vocal cords)
resonator
an object that attenuates or amplifies the signal from a generator
free vibration
ex: plucked string, as soon as string is set into motion, damping occurs due to impedance (measure of how much medium resists movement)
forced vibration
ex: shouting at an undamped guitar; if fundamental frequency of driver is close to the natural frequency of the string, the string will resonate/vibrate
outer ear function
protection, sound localization, modification of sound waves
ear canal
resonant properties cause us to have greater sensitivities to frequencies between 1kHz and 6 kHz
middle ear parts
malleus - incus - stapes
middle ear function
amplify transmission of sound waves from outer ear to inner ear, transforms signal from air to fluid, matches pressure of inside ear to external world
inner ear “cochlea” function
transduction: mechanical vibration turned into electrochemical signals
basilar membrane
wider towards the apex, acts as a bandpass filter, apex processes low frequencies and base processes high frequencies
organ of corti
includes the inner and outer hair cells
stereocilia
gated ion channel created by movement of inner hair cells that depolarize (send potassium ions out)
tonotopic organization
ability to tune into certain frequencies; inner hair cells, neurons, auditory cortex all organized according to frequencies
Descending pathways
from the brain signals travel to synapses in the cochlea; tells your ear to be less responsive
ascending pathways
signals go from ears to the brain to be processed (temporal lobe)
place coding
firing rate of neurons matters; frequency coding is determined by how often neurons fire (fire more with corresponding frequency)
temporal coding (phase locking)
when neurons fire matter; neurons and inner hair cells respond corresponding to which part of the wave is coming into the ear
adaptation
decrease firing rate even though stimulus hasn’t ended (get’s used to sound)
saturation
maximum firing rate (plateaus)
spontaneous activity
even in quiet, most neurons show background firing activity
