Exam 1 Flashcards
sound working definition
In the strictest sense, sound is a compressional wave that produces a sensation in the human air
True or False: Sound is both perceptual and physiological.
True
perceptual sound
-sensation of hearing
-the way we perceive the properties of the sound
-sound will only exist if there is a functional listener
physical perspective of sound (physiological)
-anything that produces a sound HAS to be capable of vibrations
-must possess 2 properties: mass and elasticity (everything in nature has these)
meaning of physical perspective of sound
everything in nature can vibrate, therefore everything in nature is capable of being a source of sound
-anything in nature can be both the source and medium of a sound
mass working definition
in terms of sound, mass is the amount of matter present via a solid; liquid, or gas that is capable of vibratory motion
mass
the amount of matter present
weight
the product of the gravitational force exerted on that matter
elasticity working definition
the property of all matter via solid, liquid, or gas which allows it to undergo distortion of either shape or volume when force is applied
elastic limit
the point at which crossed no longer allows that matter to return to its original form
equilibrium
-state of rest
-not making sound
-has not been forced to do anything
Newton’s first law
all bodies remain at rest of in a state of uniform motion unless another force acts in opposition
inertia working definition
-tendency of a body in motion is to remain in motion
-tendency of a body at rest is to remain at rest
the amount of inertia
directly proportional to its mass
Newton’s third law
for every force, there must be an equal reaction force in the opposite direction
True or False: A force can act along
False: you cannot have a force acting along, there must be a reaction force
cycle of vibration
one cycle of vibration is equal to equilibrium to maximum displacement in one direction, back through equilibrium to maximum displacement in the opposite direction, back to equilibrium
medium
-has to be able to vibrate
-needs mass and elasticity
-air is in a state of equilibrium and each molecules remains equidistant and exerts equal pressure
characteristics of air
each molecule of air maintains an equal distance from all other molecules of air, with each molecules of air exerting equal amount of pressure
density working definition
the amount of mass per unit volume
mass vs. density
sea level: dense
colorado: not dense
elasticity of air
-can be distorted
-can create changes in density
-air will have a tendency to move back to its original state
-still not touching, still maintaining equal pressure
area of compression
more molecules of air present than there are at equilibrium
areas of compression
more molecules of air present than there are at equilibrium
areas of rarefaction
fewer molecules of air present than there are at equilibrium
soundwave
propagated by series of density changes in the medium
greater maximum displacement of a source
greater maximum displacement of medium
simple harmonic motion
the wave of disturbance transmitted through the medium when you have a sound of a single frequency
if a sine wave has high density (compression)
-equilibrium
-displacement: minimum
-pressure: minimum
-velocity: maximum
if a sine wave has low density (rarefaction)
-displacement: maximum
-pressure: maximum
-velocity: minimum
spatial properties of sine waves
-the relative position of a molecule of air at a given instant in time
-amplitude
-wavelength
amplitude
maximum displacement of a molecule of air
amplitude vs loudness
-amplitude is physiologic (can be measured)
-loudness if psychologic (cannot be measured)
peak amplitude
the linear measurement from equilibrium to the point of displacement in one direction
Peak-to-Peak amplitude
the linear measurement from the point of maximum displacement in one direction to the point of maximum displacement in the opposite direction
RMS value
-root-mean-square
-absolute measure
-takes into account that amplitude decreases as a function of time and amplitudes varies from one cycle to the next
How to calculate RMS (long way)
-square the peak amplitude twoard positive
-square the peak amplitude toward negative
-add together
-average and find the square root
how to calculate RMS (short way)
A=1.1414 OR A*0.707
wavelength
the linear measure that refers to the distance a sound wave can travel during one complete cycle of vibration
temporal properties of sine wave
-refers to the movement of a single molecule over a period of time
-cycle
-period
-frequency
period
time it takes to complete one cycle of vibration
frequency
the number of complete cycles that occur during a certain timeframe
frequency and pitch relationship
-as frequency increases, our perception of the pitch of a sound increases
-as frequency decreases, our perception of pitch decreases
-frequency is physiologic (can be measured)
-pitch is perceptual (cannot be measured)
pitch formula
Pitch= 1/ Frequency
in seconds
frequency formula
frequency= 1/ period
in Hz
frequency and wavelength relationship
-as frequency increases wavelength decreases
-as frequency decreases, wavelength increases
wavelength formula
wavelength= velocity/ frequency
measured in ft
frequency formula
frequency=velocity/wavelength
measured in Hz
velocity ALWAYS equals
1,130 ft/sec
type of wave motion
-longitudinal and transverse wave motion
longitudinal wave motion
the direction of air particle movement is parallel to the direction of wave movement
transverse wave motion
the direction of vibration in the air is at the right angle to the direction the wave is moving
phase definitoin
the particle position within a cirlce of motion at a given instant in time
phase will determine what happens when sound is
combined
complex sounds
any sound composed of 2 or more simple sinusoids
in phase
the areas of rarefaction/compression occur at the exact same time
in phase characteristics
-frequency: same
-amplitude: same
-starting phase: same
out of phase
the areas of rarefaction/compression do not occur at the exact same time
2 sounds out of phase
create new sound with new frequency and increased amplitude
2 sounds that are 180 degrees out of phase
the areas of compression/rarefaction occur in direct opposition to each other
dead spot/area of silence
2 waves cancel each other out
