[PPT] - INTRODUCTION TO MUSICAL TIMBRE YU / LAMONT FEBRUARY 20, 2018 PowerPoint Presentation

SLIDE 1

INTRODUCTION TO MUSICAL TIMBRE

YU / LAMONT FEBRUARY 20, 2018

LINGUIST 197M, SPRING 2018. CLASS 5.1

SLIDE 2

LINGUIST 197M, SPRING 2018. CLASS 5.1

CHROME MUSIC LAB: PIANO ROLL

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http://musiclab.chromeexperiments.com/Piano-Roll

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LINGUIST 197M, SPRING 2018. CLASS 5.1

CHROME MUSIC LAB: SPECTROGRAM

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http://musiclab.chromeexperiments.com/Spectrogram

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BRIEF REMINDER: HARMONICS AND COMPLEX WAVES

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LINGUIST 197M, SPRING 2018. CLASS 5.1

FROM PURE TONES TO COMPLEX WAVES

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http://musiclab.chromeexperiments.com/Sound-Waves

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LINGUIST 197M, SPRING 2018. CLASS 3.1

EXERCISE: SOUND OF ADDING IN HARMONICS

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https://soundphysics.ius.edu/?page_id=949

Can you adjust the amplitudes

f the harmonics to get the

timbre to sound like some instrument you like?

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LINGUIST 197M, SPRING 2018. CLASS 3.1

DEMO: COMPLEX WAVES

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https://musiclab.chromeexperiments.com/Oscillators

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LINGUIST 197M, SPRING 2018. CLASS 3.1

BUILDING UP A SQUARE WAVE WITH SINES

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https://en.wikipedia.org/wiki/User:LucasVB/Gallery#/media/File:Synthesis_square.gif

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LINGUIST 197M, SPRING 2018. CLASS 3.1

BUILDING UP A SQUARE WAVE

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https://en.wikipedia.org/wiki/User:LucasVB/Gallery#/media/File:Fourier_transform_time_and_frequency_domains.gif

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LINGUIST 197M, SPRING 2018. CLASS 3.1

TWO REPRESENTATIONS OF SQUARE WAVE

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https://en.wikipedia.org/wiki/User:LucasVB/Gallery#/media/File:Fourier_transform_time_and_frequency_domains.gif

Time domain: waveform Frequency domain: spectrum

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LINGUIST 197M, SPRING 2018. CLASS 3.1

HARMONIC AMPLITUDES

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https://sites.google.com/a/georgiasouthern.edu/julia-inozemtseva/teaching-math-animations-and-pics? tmpl=%2Fsystem%2Fapp%2Ftemplates%2Fprint%2F&showPrintDialog=1#TOC-Fourier-Series

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LINGUIST 197M, SPRING 2018. CLASS 3.1

BUILDING UP A TRIANGLE WAVE WITH SINES

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https://en.wikipedia.org/wiki/User:LucasVB/Gallery#/media/File:Fourier_transform_time_and_frequency_domains.gif

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LINGUIST 197M, SPRING 2018. CLASS 5.1

ADDITIVE SYNTHESIS

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http://meettechniek.info/additional/additive-synthesis.html

Can you use an additive synthesizer to try to replicate the timbre of an instrument?

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RESONANCE

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LINGUIST 197M, SPRING 2018. CLASS 5.1

RESONANCE

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Rossing (1990): The Science of Sound.

Resonance occurs when a force applied to a vibrating system varies with a frequency at or near the natural frequency of a system

http://stmary.ws/HighSchool/Physics/home/notes/waves/animations/AnimFact/ swing_set_playground_traci_closeup_hg_wht.gif

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LINGUIST 197M, SPRING 2018. CLASS 5.1

BREAKING A WINE GLASS WITH SOUND

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http://courses2.cit.cornell.edu/physicsdemos/secondary.php?pfID=17

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LINGUIST 197M, SPRING 2018. CLASS 5.1

STRING RESONANCE

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Strings naturally vibrate at a fundamental frequency, and at harmonics that are integer multiples of the fundamental

https://upload.wikimedia.org/wikipedia/commons/5/5c/Standing_waves_on_a_string.gif

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LINGUIST 197M, SPRING 2018. CLASS 5.1

CHROME MUSIC LAB: STRING RESONANCE

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https://musiclab.chromeexperiments.com/Strings https://musiclab.chromeexperiments.com/Harmonics

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LINGUIST 197M, SPRING 2018. CLASS 5.1

MOVIES: STRING RESONANCE

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https://youtu.be/ttgLyWFINJI https://youtu.be/oZ38Y0K8e-Y?t=8s

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LINGUIST 197M, SPRING 2018. CLASS 5.1

STRING RESONANCE: CALCULATIONS

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How long is the wavelength relative to the length

f the string for the fundamental?

https://upload.wikimedia.org/wikipedia/commons/5/5c/Standing_waves_on_a_string.gif

The “length” of a standing wave vs. the cycle “length” of a traveling wave: wavelength in space is like period in time for a traveling wave

SLIDE 21

LINGUIST 197M, SPRING 2018. CLASS 5.1

SYMPATHETIC VIBRATION: TUNING FORKS

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Other fun resonance videos at: http://blog.prosig.com/2011/09/20/5-videos-that-explain- resonance/

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LINGUIST 197M, SPRING 2018. CLASS 5.1

EXAMPLE: SYMPATHETIC RESONANCE

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B resonates to A if B’s vibrations make A vibrate too. Effect: B has more energy than it did The closer B’s natural frequency is to A’s the stronger the vibrations of B

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SLIDE 23

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WAVEFORMS, SPECTRA, AND SPECTROGRAMS

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LINGUIST 197M, SPRING 2018. CLASS 5.1

SYNTHESIZE A VOCALIC SOUND…

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LINGUIST 197M, SPRING 2018. CLASS 5.1

REVIEW: FIND PERIOD FROM THE WAVEFORM

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What are the x- and y-axes in the waveform? What’s that blue line?

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LINGUIST 197M, SPRING 2018. CLASS 5.1

REVIEW: TAKE SPECTRAL SLICE (SPECTRUM)

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Make sure you select a window of at least 5 cycles of the waveform to take the spectral slice over!

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LINGUIST 197M, SPRING 2018. CLASS 5.1

REVIEW: UNDERSTANDING THE SPECTRUM

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Make sure to zoom in on the spectrum! What are the axes? How far apart are two adjacent spectral peaks and why?

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LINGUIST 197M, SPRING 2018. CLASS 5.1

NEW: THE SPECTROGRAM!

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LINGUIST 197M, SPRING 2018. CLASS 5.1

NEW: THE SPECTROGRAM!

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SLIDE 30

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FROM THE SPECTRUM TO THE SPECTROGRAM

SLIDE 31 0.0 0.5 1.0 1.5 2.0

1.0

0.5 t f = 1 Hz 0.0 0.5 1.0 1.5 2.0

1.0

0.5 t f = 2 Hz 0.0 0.5 1.0 1.5 2.0

1.0

0.5 t f = 3 Hz 0.0 0.5 1.0 1.5 2.0

1.0

0.5 t f = 4 Hz

f = 1 Hz f = 2 Hz f = 3 Hz f = 4 Hz

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LINGUIST 197M, SPRING 2018. CLASS 5.1

SPECTRUM OF COMPLEX WAVEFORM

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0.0 0.5 1.0 1.5 2.0 5 10 15 20 t wave.complex

1 2 3 4 Amplitude (dB) 1 Frequency (Hz) Amplitude (dB) Time (s)

SLIDE 33

LINGUIST 197M, SPRING 2018. CLASS 5.1

SPECTRUM OF COMPLEX WAVEFORM

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0.0 0.5 1.0 1.5 2.0 5 10 15 20 t wave.complex

1 2 3 4 Amplitude (dB) 1 Frequency (Hz) Amplitude (dB) Time (s)

Waveform: x-axis is time Spectrum: x-axis is frequency

SLIDE 34

LINGUIST 197M, SPRING 2018. CLASS 5.1

FROM SPECTRUM TO SPECTROGRAM: STEP 1

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1 2 3 4 Amplitude (dB) 4 3 2 1 Freq (Hz) 1 2 3 4 Amplitude (dB) 4 3 2 1 Freq (Hz) Rotate clockwise

SLIDE 35

LINGUIST 197M, SPRING 2018. CLASS 5.1

FROM SPECTRUM TO SPECTROGRAM: STEP 2

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1 2 3 4 Frequency (Hz) 1 2 3 4 Amplitude (dB) 1 2 3 4 Amplitude (dB) 4 3 2 1 Freq (Hz) Flip vertically

SLIDE 36

LINGUIST 197M, SPRING 2018. CLASS 5.1

FROM SPECTRUM TO SPECTROGRAM: STEP 3

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1 2 3 4 Frequency (Hz) 1 2 3 4 Amplitude (dB) 1 2 3 4 Encode amplitude levels (the height/ length of the blue spikes) in grayscale* *or with heat map

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LINGUIST 197M, SPRING 2018. CLASS 5.1

FROM SPECTRUM TO SPECTROGRAM: STEP 4

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1 2 3 4 Frequency (Hz) 1 2 3 4 Frequency (Hz) 1 2 3 4 Amplitude (dB) Encode amplitudes in grayscale… …at time t1

SLIDE 38

LINGUIST 197M, SPRING 2018. CLASS 5.1

FROM SPECTRUM TO SPECTROGRAM: STEP 5

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1 2 3 4 Frequency (Hz) Line up spectral slices taken over time… t1 t2 t3 t4 t5 t6

SLIDE 39

LINGUIST 197M, SPRING 2018. CLASS 5.1

FROM SPECTRUM TO SPECTROGRAM: FINIS

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…and you have a spectrogram

Time (s) 0.8772 1.128 5000 Frequency (Hz)

SLIDE 40

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MUSICAL INSTRUMENTS AND TIMBRE

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LINGUIST 197M, SPRING 2018. CLASS 5.1

RECORDINGS OF INSTRUMENTS IN PRAAT

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Homework: bring in a musical instrument Thursday! Let’s do some recordings of your musical instruments in Praat!

SLIDE 42

LINGUIST 197M, SPRING 2018. CLASS 5.1

REAL-TIME OSCILLOSCOPE

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http://academo.org/demos/virtual-oscilloscope/

SLIDE 43

LINGUIST 197M, SPRING 2018. CLASS 5.1

REAL-TIME SPECTRUM ANALYZER

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http://academo.org/demos/spectrum-analyzer/

SLIDE 44

LINGUIST 197M, SPRING 2018. CLASS 5.1

REAL-TIME SPECTRUM ANALYZER II

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http://musiclab.chromeexperiments.com/Spectrogram