Please be Seated. The physics of sound: What makes musical tones different? Special Lecture for the...
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Transcript of Please be Seated. The physics of sound: What makes musical tones different? Special Lecture for the...
Pleasebe
Seated
The physics of sound:What makes musical
tones different?
Special Lecture for the 2005 Year of Physicsin coordination with the
French National Center for Scientific Researchand the
French Embassy in Washington DC
Special Guests:
Michẻla Castellengo, Research Director, Musical Acoustics Lab, University of ParisHugues Genevoire, Research Engineer, Musical Acoustics Lab, University of ParisCharles Besnainous, Research Engineer, Musical Acoustics Lab, University of ParisJoseph Curtin, stringed instrument makerBenoît Rolland, bow makerSerge de Laubier, musician-researcher
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:Any complex wave can be“synthesized” by adding itsharmonics together with the
proper amplitudes and phases.
“Fourier synthesis” and “Fourier analysis”
Fourier Synthesis
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
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
Vocal Formants
Origin of Vocal Formants(~17.5 cm closed tube)
Frequency:
f1 = 500 Hz
f3 = 1500 Hz
f5 = 2500 Hz
Vocal range:
150-850 Hz
500-2500 Hz
1500-3500 Hz
Mode:
Simple formant model
From Thomas D. Rossing, The Science of Sound, second edition
Vowel formant production
Source: http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html
Vowel Formant Frequencies
From Donald E. Hall, Musical Acoustics, Second Edition
TheSingersFormant
Averaged spectral energy distribution:Light: ordinary speechDark: orchestral accompanimentBrown: Good singer with orchestra
Johan Sundberg: The Acoustics of the Singing Voice; Sci. Amer., March 1977
Sound Spectrograms
Vocal Formant spectra
“OO”
“AH”
“EE”
Vocal Spectrogram of Formants
Voice and Synthesizer “wow”
Matching vocal spectrograms
Kay Elemetrics, Computerized Speech Laboratory
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 EndThank you for your attention
We are on the web at
http://www.physics.umd.edu/lecdem/
Animated Gifs compliments of bellsnwhistles.com