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String vibrate at
even and odd multiples
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Tubes vubrate at
odd multiples
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Free vibration
- object vibrating at its natural frequency
- ex) tuning fork, string, column of air in a tube closed at one end
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Natural frequency is determined by
length, mass, and stiffness of an object
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forced vibration
- using on vibrating system to cause another to vibrate
- ex) holding a tuning fork on a table - forcing it to vibrate
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driving force
the energy being supplied (tuning fork)
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driven system
the system to which the energy is being supplied (table)
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Will every driving force make the driven system vibrate?
NO
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Resonance is all about
the frequency of the driving force and the natural frequency of the driven system
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Resonance occurs
when the frequency of te driving force is at or near the driven system
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the closer the frequency of the driving force is to the natural frequency od the driven system...
the lower the amplitude of the forced vibration
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Resonance curves (frequency response curves) show the relationship between
the frequency of the driving force and the amoplitude of forced vibration.
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Peaks of amplitude occur when
the frequency of the driving force matches the natural frequency of the driven system (resonance).
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lightly damped
high amplitude of forced vibration, restricted range of frequencies resonated
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highly damped
low amplitude of forced vibration, broad range of frequencies resonated
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Is the vocal tract highly or lightly damped?
highly damped
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What can be resonated?
Anything that can vibrate
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Examples of air-filled resonators
- tube
- simple Helmholtz resonator
- double Helmholts resonator
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What are important characteristics of air filled resonators?
- volume
- length of neck
- opening
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Which example if an air-filled resonator is a model for the vocal tract?
Double Helmholts Resonator
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In the double Helmholtz resonator,
l1 and A1 represent
l2 and A2 represent
- tongue constriction
- lip constriction
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In tube vibration f0, f3, f5 correspond with
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In string vibration, f0, f2, f3, f4 correspond with
- f0 = F1
- f2 = F2
- f3 = F3
- f4 = F4
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The resonant frequencies of the air-filled tube will match the..
natural frequencies of the tube when pulsed
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Perturbation theory describes
the effects of constriction, or perturbations, on the resonant frequencies / quality of sound of the tube
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Pertrbation theory explains that
- constriciton near antinodes decrease resonant frequencies
- constriction near nodes increase resonant frequencies
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The tube will resonate frequencies that
match its natural frequencies
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Resonance are...
Filters are...
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filters
opposite sid eof the rsonator coin
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resonation looks at the
output in terms of the frequencies that are enhanced
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filters look at
the output in temr of the frequencies that are absorbed or reduced in energy
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