Chapter 3 Flashcards
psychoacoustics
what happens in brain and how we perceive sound
study of the relationship between physical stimuli and psychological responses to which they give rise.
physical acoustics
science of sound
sound
is a propagated change or disturbance in the density, and therefore in the pressure of an elastic medium.
sound travels through air in the form of
waves
sound wave
a period of compression and a period rarefaction
Brownian motion
the rapid and random movement of air particles
solid is more elastic than______ and liquid is more elastic than a _____
liquid, gas
All mechanical waves require
1) some source of disturbance
2) a medium that can be disturbed
3) some physical connection through which adjacent portion of the medium can influence each other.
sound travels by
moving objects such as loud speaker and moving air such as organ pipes
transverse is _______________to sound wave
perpendicular
longitudinal wave
a wave in which the particles of the medium move along the same axis as the wave
frequency
the number of complete oscillations of a vibrating body per unit of time. in Acoustics the unit of measurement is cycles per second (CPS) or hertz (Hz).
sinewave
the waveform of a pure tone showing simple harmonic motion
pure tone
a tone of only one frequency
The two major effects on frequency are
mass and stiffness
resonant frequency
the natural rate of vibration of a mass
amplitude
max height above resting spot; the extent of the vibratory movement of a mass from its position of rest to that point farthest from the position of rest
few rarefactions and compressions means a _____frequency sound
low
small amplitude
soft sounds
infrasound
frequency too low for human hearing
ultrasound
frequency too high for humans to hear
velocity of a sound wave
the speed with which it ravels from the source to another point
when temperature and humidity increase the speed of sound_____
increases
wavelength
distance between peaks, measured from any point on the pressure wave to the same point on the next wave.
phase
the relationship in time between two or more waves
in phase
two waves exactly equal, increase amplitude
out of phase
cancel each other out, there is silence
fundamental frequency
the lowest frequency of vibration in a complex sound
periodic sounds
no overtone, exactly one frequency, a complex sound that repeats over time.
aperiodic sounds
vary randomly over time, do not have fundamental frequencies and are usually perceived as noise.
power of a sound goes with _______of a sound
intensity
intensity
the amount of sound energy per unit of area
dyne
is how much pressure a sound causes
the force required to accelerate a mass of one gram at a rate of one centimeter per second squared.
decibel based on a _________ scale
logarithm
zero decibels means
the softest sound the best ears can hear
dB Intensity Levels
how much power to make sound - watts/cm^2 (intensity levels double increased by 3)
dB sound pressure level
how much pressure change - dyne/cm^2 (sound pressure level doubles increased by 6)
dB Hearing level
decibel level for testing human hearing
dB sound level
sound level above the patients threshold
quality
the vividness or identifying characteristics of a soudn
All sound waves posses
speed, frequency, wavelength, phase, period and amplitude
All sound waves also reflect
echo, diffract and reverberate
loudness
psychological experience most directly related to sound pressure/intensity
The psychological correlate of frequency is
pitch
The decibel reference on audiometers is
hearing level
Pitch
the subjective impressions of the highness or lowness of a sound
Mel
is a perceived scale of pitches judged by listeners. how a person perceives pitch
Phon
psychoacoustic measure of loudness
localization
the ability to determine the specific location of a sound source
critical bands
regions in the cochlea where the hearing nerves allow us to perceive different pitches.
masking
the threshold shift of one sound that is caused by the introduction of a second sound
Impedance
the opposition it offers to the transmission acoustic energy. Stopping sound wave
pure tone audiometer
the device allows for a comparison of any persons hearing threshold to that of an established norm
loudness levels
-10 to 120 dB HL
audiometer earphones are use to test hearing by
air conduction
bone conduction
an oscillator is placed on the forehead or mastoid to test hearing
Speech Audiometer
test through speaker need to be calibrated
usual range is from -10 to 110 dB HL
audiometers measure frequency and intensity. The frequencies range from
250 Hz to 8000 Hz.
period
1/frequency. Time of complete vibration
source of vibration
such as vocal folds
Source of energy
how much power it takes to produce the speech is IL watts/cm^2
a medium
causes changes in pressure
receiver
we use the decibel scale to represent how loud or soft the voice is
sound acts the same no matter what/who produces it
True
two sine waves may be contrasted by their difference in ________, _________, and _______
frequency
intensity
phase
Discussion of decibels meaningless without a _______
reference
velocity of sound is its ______
speed
Number of beats per second is determined by the difference between two _________
frequencies
Sound wave made up of a number of different sinusoids with each different frequencies
complex wave
Increased threshold air conduction and bone conduction
sensorineural
hearing loss by air conduction
conductive hearing loss
bony protrusion is in ______
mastoid
normal air conduction threshold
normal hearing
sound travels through ear in form of this _______
sound wave
waveform of a pure tone showing simple harmonic motion
sine wave
waves are describes as ______ and _______
compressions and rarefactions
another name for cycles per second
hertz
number of complete oscillations of a vibrating body per unit of time
frequency
cochlea
organ of hearing
a decrease in strength of sound
attenuation
auditory nerve
connects ear to brain
barotrauma
sudden changes of pressure
