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Acoustics Tutorial
Acoustics = Sound = A change in local atmospheric pressure that we can hear
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Sound has an amplitude and a frequency.
1.1 Hz to 20 Hz is infrasound. (inaudible)
20 Hz to 20KHz is sound. (Pulmonator needs 20Hz to 60 Hz)
20 KHz and above is ultrasound. (inaudible)
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Sound requires a medium to propagate. No medium = No sound
Sound can be reflected, refracted, focussed, and
waveguided.
Resonance is a special
quality of sound to oscillate
at a greater amplitude at
some frequencies than
others.
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Resonance
The frequency of sound that causes vibrations of the
greatest amplitudes is called resonant frequency.
Sympathetic resonance is a harmonic phenomenon where a
formerly passive vibratory body responds to external
vibrations to which it has a harmonic likeliness.
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Pulmonator
Pulmonator works on the principle of sympathetic
resonance.
The resonant frequency of healthy human lungs is around
39 Hz.
