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What is sound?
Air Pressure P=F/A
Pressure=Force/Area
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Pressure is measured in
pascals/ micropascals or "dyne"
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Subscript denotes the type or location of the pressure.
- P atoms
- P neg
- P trach (open=same pressure)
- P oral (open=same pressure)
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Air volume
quantity of air contained ina 3-D space
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Air movement/ flow
quantity of gas that move through a given area in a unit of time
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Boyles law
describes relationship between pressure, and volume, and temp
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Pressure is high
volume is high
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vibration/ oscillation
back/ forth motin
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compression/rarefaction
areas of high/low pressure
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elasticity/interia
opposing forces that keep molecules in motion until acted upon by other physical law that "settle them down".
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sound
changes in air pressure
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amplitude and damping
frictional forces reduce the amplitude of the molecular motion thus damping the vibrations
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opposing forces are equal then no change
interia
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Newton's lst law
- an object in motion stays in motion
- an object at rest stays at rest
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Newton's 2nd law
when a net forces act upon an object the object acclerates in the same direction of the force.
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Accleration is directly proportional
to the net force and inversely proportional to the mass
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F=Ma
Force=Mass(acceleration)
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force is measured in
Newtons
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Males have _____ vocal cords
heavy, more mass
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Newton's 3rd law of motion
for every action (force) there is an equal and opposite reaction (force)
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Characteristics of sound waves
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more cycles
more Hz, higher pitch
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less cycles
more Hz, slower pitch
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transverse
molecule moves perpendicular to the direction of the wave
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longitudinal
molecule moves along the same axis as the wave
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sine
waveform of a pure tone, graph of the vibration
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wavelength
measured from one point on a wave to the same point on the next cycle-related to the freq. of the wave
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complex sounds are
periodic or aperiodic
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fundamental freq.
Fo measured in Hz
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wavelength
dension of space
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Noise Harmonic Ratio
breathy
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the time that each cycle in a wave takes to occur
is its period
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Human vocal folds normally vibrate between
80-500 Hz in speaking situations
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healthy ears
low as 20 to high as 20, 000 HZ
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subsonic
too low to be audible, may be felt
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ultrasonic
too high to be audible
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0 dB
threshold of hearing
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30 dB
conversation, sound travels faster through water
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"breaking sound barrier"
traveling faster than speed of sound
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amplitude
the magnitude of pressure changes in a sound and measured in micobar or micropasals
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the shape of a resonator is not as imporant as
its volume when determining the freq to which it will resonate
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the vocal tract/ear canal are
acoustic resonators
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acoustic resonator
volume of air enclosed in a container can resonate
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sound consists of increases and decreases in air pressure caused by the movement of a source
tuning fork
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sound waves are characterized by different dimensions of
frequency, period, wavelength, amplitude, and intensity
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sound waves can consist of one frequency (?) and many frequencies (?)
pure tone, complex waves
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t or f sound waves can be visually depicted on waveforms and spectra
t
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amplitude and intensity of sounds can be measured conveniently on the decibel scale t or f
t
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resonance involves forced vibration in which an object or container of air is set into vibration by the action of another vibration tor f
t
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acoustic resonator may be sharply or broadly tuned, with different center frequencies and upper and lower cutoff frequencies t or f
t
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