Module 1 Flashcards
(20 cards)
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vibrations are transmitted
if transmitted to a listener’s ear and processed through the listener’s auditory system these vibrations will be perceived as ?
disturbance creates vibrations in a medium
- gases
- liquids
- solids
through the medium
sound
Molecular Movement
air is a gas made up of
air molecules are not?
- constantly?
- random
- high
Will ?
- with other
- with ?
collision produces ?
pressure is a ?
pressure can be ?
molecules
stationary
-moving (Brownian motion)
patterns
-speeds
collide
- air molecules
- anything in their path
pressure
- force, acts perpendicularly on a surface
- measured
Air movement:
air molecules move in ?
air molecules tend to ?
air molecules move from an area of ?
movement of air through a certain area within a given period of time is called?
predictable ways
equalize
area of high pressure to an area of low pressure
flow
Pressure change terms:
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ambient pressure Pam: relatively
positive pressure (Ppos): pressure that is relatively ?
Negative pressure (Pneg): pressure that is relatively
location
- 100 kPa
- 14.7 psi
- 1,000,000 dynes/cm2
constant pressure in a given place or time
higher than atmospheric pressure
lower than atmospheric pressure
Air flow terms:
flow: movement of air through ?
volume velocity: speed of a volume of air
driving pressure: difference in pressure causing the air to ?
laminar flow: air flowing ?
turbulent flow: air flow is disturbed by an ?
a certain area within a given period of time
flowing in a certain direction
flow from a higher pressure area to a lower pressure area
smoothly, molecules moving in parallel and at the same speed
obstacle, causing flow to be less regular and to have random variations in pressure
pressure, volume and density:
pressure:
volume:
density:
Pressure volume and density are systematically related:
- volume and pressure are
- density and pressure are
force acting perpendicularly on a surface
three dimensional amount of space that is occupied
amount of mass per unit of volume
- inversely related (Boyles law)
- proportionally related
Boyle’s law:
given a constant temperature, increasing the volume of an enclosed space will ?
given constant temperature decreasing the volume of an enclosed space will?
decrease the air pressure within that space
increase the air pressure within that space
Initiating motion:
to generate sound the ambient pressure must be ?
this change in pressure is accomplished by the application of ?
disturbed in a way creating pressure increases and decreases in a systematic manner
force sufficient to disrupt the brownian motion of air molecules
Elasticity and inertia:
elasticity (restoring force): the property of an object to return to its original ? after being ?
-the amount of restoring force depends upon the amount or extent
location, size, form, or shape/ displaced, deformed or stretched
-which the object was originally displaced, deformed or stretched
Inertia: this law of physics holds that objects at rest tend too ? unless? ; objects in motion tend to remain? unless?
remain at rest unless acted upon by an outside force/ in motion in a fixed direction/ acted upon by an outside force
Hooke’s Law: the restoring force of elasticity is ?
proportional to the amount of displacement or deformation undergone by the object. it acts in the opposite direction
Amplitude: the maximum distance the molecule is ?
damping: decrease in ? as the result of a?
simple harmonic motion: ..,..,.. movement of an object with a characteristic pattern of ?
displaced away from its resting position , determined by the amount of energy involved in the movement
amplitude of movement/force opposing the movement
regular, smooth, back and forth movement of an object /acceleration through the resting position and deceleration at the endpoints of the movement
Compression: molecules are displaced from ? and ?
when molecules have been displaced in this manner and are approaching and colliding with the next group of molecules, there is an?
increased density results in an ? thus when molecules approach and collide, an area of ? results
their original positions/push against neighboring molecules
increased density of air in that area
increase of pressure / positive pressure known as compression
rarefaction: as molecules down the line are displaced toward their neighbors, molecules that were earlier displaced are already? rather than stopping at the original position, the molecules returning toward equilibrium ? this increases the distance between the two groups of molecules involved, decreasing ? resulting in an area of ? known as?
returning to their equilibrium positions/ overshoot their marks and swing farther away to the other side of their original positions/ density air intuit region/ low pressure/ rarefaction
sound travels in ?
in …. waves in air
may also travel in ?
in all ?
the total energy of the sound wave is ? so sound wave amplitude ?
wave front: the ?
waves
- longitudinal
- transverse or torsional waves in solids
directions, spherically
-constant/decreases as a function of distance from the sound source
outermost edge of the sphere in which sound travels
Wave cycles:
a cycle of vibration is one ? from the initial resting position to the point of ? and then returning to ?
for sound we usually discuss cycles in terms of pressure changes rather than molecule positions, so one cycle would include ?
complete back and forth movement of the molecule / maximal displacement back through resting position to the point of maximal displacement in the opp. direction / rest position
baseline, compression, return to baseline, rarefaction, and return to baseline
Frequency and Pitch:
frequency: the number of ?
hertz: the unit now used for ?
- a wave with 100 cycles per second has a frequency of ?
- A wave with 345 cycles per second has a frequency of ?
Pitch: the psychophysical correlate of? how humans ? related to but not identical to
mel: the unit for
mel scale:
cycles per second ( cps)
measuring frequency
- 100 Hz
- 345 Hz
frequency/ perceive freq. / freq.
measuring pitch
perceptual, subjective scale for measuring pitch
Period: the amount of time needed for
measured in ?
symbolized by
the inverse of
each cycle
time ,
t
frequency
Where F= frequency and t=
F=
t=
freq. / period
1/t
1/f
Frequency factors: an objects typical frequency of vibration will depend on several ?
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physical characteristics such as size, length, thickness, tension, mass and composition material
-length: increasing length decreases frequency
mass: increasing mass decreases frequency
stiffness/tension: increasing tension increases frequency
