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WELCOMEto
Physics is Phun
Pleasebe
Seated
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The Sounds of Science
Physics is Phun
March 2007
Reference book:
The Physics of Sound, 3rd edition (2005)
by Richard E. Berg and David G. Stork
published byPearson/Prentice-Hall
The Overtone Series
Standing waves in a string
The Overtone Series
Standing waves in air columns
The Overtone Series
Standard electronic wave forms
• Sine wave
• Sawtooth wave
• Pulse train
• Triangular wave
• Square wave
Fourier’s Theorem:Jean Baptiste Joseph Fourier (1768 - 1830)
Any physical function that varies periodically with time with a
frequency f can be expressed as a superposition of sinusoidal components of frequencies:
f, 2f, 3f, 4f, ... --from “Wikipedia”
Fourier SynthesisSawtooth wave
Fourier SynthesisPulse train wave
Fourier SynthesisTriangular wave
Fourier SynthesisSquare wave
Fourier Analysisor
Spectrum Analysis
Sine Wave Spectrum
Sawtooth Wave Spectrum
Pulse Train Spectrum
Triangular Wave Spectrum
Square Wave Spectrum
Analysis of
Musical Sounds
Fourier Analysisof
Sounds ofMusical Instruments
Recorder Wave and Spectrum
Violin Wave and Spectrum
Crumhorn Wave and Spectrum
Clarinet Wave and Spectrum
Factors in Tone Quality1. Amplitudes of harmonics
2. Attack and decay transients
3. Inharmonicities
4. Formants
5. Vibrato
6. Chorus effect
The Singing Formant
Origin of Vocal Formants(~17.5 cm closed tube)
Frequency:
f1 = 500 Hz
f3 = 1500 Hz
Vocal range:
150-850 Hz
500-2500 Hz
Mode:
Simple formant model
Origin of Vocal Formants(~17.5 cm closed tube)
Frequency:
f1 = 500 Hz
f3 = 1500 Hz
Vocal range:
150-850 Hz
500-2500 Hz
Mode:
Vowel formant production
Source: http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html
Vowel Formant Frequencies
Sound Spectrograms
Vocal formants for vowel sounds
Voice and Synthesizer “Wow”
Vocal Spectrograms
Computerized Speech Laboratory
Courtesy of Kay Elemetrics Corp.
Helium Voice
Singing frequency remains the same
(vibration of vocal folds)
Formant frequencies rise because
She >> Sair
Why?
Vowel formant production
Source: http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html
Speed of Sound in
Helium and Sulfur Hexafluoride
He SF6
M/Mair 1/7 4.6
Vs/S 2.6 0.5
The EndSee you next time!
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