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

LINGUIST 197M, SPRING 2018. CLASS 5.1 INTRODUCTION TO MUSICAL TIMBRE YU / LAMONT FEBRUARY 20, 2018

LINGUIST 197M, SPRING 2018. CLASS 5.1 2 CHROME MUSIC LAB: PIANO ROLL http://musiclab.chromeexperiments.com/Piano-Roll

LINGUIST 197M, SPRING 2018. CLASS 5.1 3 CHROME MUSIC LAB: SPECTROGRAM http://musiclab.chromeexperiments.com/Spectrogram

4 BRIEF REMINDER: HARMONICS AND COMPLEX WAVES

LINGUIST 197M, SPRING 2018. CLASS 5.1 5 FROM PURE TONES TO COMPLEX WAVES http://musiclab.chromeexperiments.com/Sound-Waves

LINGUIST 197M, SPRING 2018. CLASS 3.1 6 EXERCISE: SOUND OF ADDING IN HARMONICS Can you adjust the amplitudes of the harmonics to get the timbre to sound like some instrument you like? https://soundphysics.ius.edu/?page_id=949

LINGUIST 197M, SPRING 2018. CLASS 3.1 7 DEMO: COMPLEX WAVES https://musiclab.chromeexperiments.com/Oscillators

LINGUIST 197M, SPRING 2018. CLASS 3.1 8 BUILDING UP A SQUARE WAVE WITH SINES https://en.wikipedia.org/wiki/User:LucasVB/Gallery#/media/File:Synthesis_square.gif

LINGUIST 197M, SPRING 2018. CLASS 3.1 9 BUILDING UP A SQUARE WAVE https://en.wikipedia.org/wiki/User:LucasVB/Gallery#/media/File:Fourier_transform_time_and_frequency_domains.gif

LINGUIST 197M, SPRING 2018. CLASS 3.1 10 TWO REPRESENTATIONS OF SQUARE WAVE Time domain: waveform Frequency domain: spectrum https://en.wikipedia.org/wiki/User:LucasVB/Gallery#/media/File:Fourier_transform_time_and_frequency_domains.gif

LINGUIST 197M, SPRING 2018. CLASS 3.1 11 HARMONIC AMPLITUDES 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

LINGUIST 197M, SPRING 2018. CLASS 3.1 12 BUILDING UP A TRIANGLE WAVE WITH SINES https://en.wikipedia.org/wiki/User:LucasVB/Gallery#/media/File:Fourier_transform_time_and_frequency_domains.gif

LINGUIST 197M, SPRING 2018. CLASS 5.1 13 ADDITIVE SYNTHESIS http://meettechniek.info/additional/additive-synthesis.html Can you use an additive synthesizer to try to replicate the timbre of an instrument?

14 RESONANCE

LINGUIST 197M, SPRING 2018. CLASS 5.1 15 RESONANCE Resonance occurs when a force applied to a vibrating system varies with a frequency at or near the natural frequency of a system Rossing (1990): The Science of Sound. http://stmary.ws/HighSchool/Physics/home/notes/waves/animations/AnimFact/ swing_set_playground_traci_closeup_hg_wht.gif

LINGUIST 197M, SPRING 2018. CLASS 5.1 16 BREAKING A WINE GLASS WITH SOUND http://courses2.cit.cornell.edu/physicsdemos/secondary.php?pfID=17

LINGUIST 197M, SPRING 2018. CLASS 5.1 17 STRING RESONANCE https://upload.wikimedia.org/wikipedia/commons/5/5c/Standing_waves_on_a_string.gif Strings naturally vibrate at a fundamental frequency, and at harmonics that are integer multiples of the fundamental

LINGUIST 197M, SPRING 2018. CLASS 5.1 18 CHROME MUSIC LAB: STRING RESONANCE https://musiclab.chromeexperiments.com/Harmonics https://musiclab.chromeexperiments.com/Strings

LINGUIST 197M, SPRING 2018. CLASS 5.1 19 MOVIES: STRING RESONANCE https://youtu.be/ttgLyWFINJI https://youtu.be/oZ38Y0K8e-Y?t=8s

LINGUIST 197M, SPRING 2018. CLASS 5.1 20 STRING RESONANCE: CALCULATIONS 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 How long is the wavelength relative to the length of the string for the fundamental?

LINGUIST 197M, SPRING 2018. CLASS 5.1 21 SYMPATHETIC VIBRATION: TUNING FORKS https://youtu.be/zWKiWaiM3Pw Other fun resonance videos at: http://blog.prosig.com/2011/09/20/5-videos-that-explain- resonance/

LINGUIST 197M, SPRING 2018. CLASS 5.1 22 EXAMPLE: SYMPATHETIC RESONANCE 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 22

23 WAVEFORMS, SPECTRA, AND SPECTROGRAMS

LINGUIST 197M, SPRING 2018. CLASS 5.1 24 SYNTHESIZE A VOCALIC SOUND…

LINGUIST 197M, SPRING 2018. CLASS 5.1 25 REVIEW: FIND PERIOD FROM THE WAVEFORM What are the x- and y-axes in the waveform? What’s that blue line?

LINGUIST 197M, SPRING 2018. CLASS 5.1 26 REVIEW: TAKE SPECTRAL SLICE (SPECTRUM) Make sure you select a window of at least 5 cycles of the waveform to take the spectral slice over!

LINGUIST 197M, SPRING 2018. CLASS 5.1 27 REVIEW: UNDERSTANDING THE SPECTRUM Make sure to zoom in on the spectrum! What are the axes? How far apart are two adjacent spectral peaks and why?

LINGUIST 197M, SPRING 2018. CLASS 5.1 28 NEW: THE SPECTROGRAM!

LINGUIST 197M, SPRING 2018. CLASS 5.1 29 NEW: THE SPECTROGRAM!

30 FROM THE SPECTRUM TO THE SPECTROGRAM

0.5 f = 1 Hz f = 1 Hz -1.0 0.0 0.5 1.0 1.5 2.0 t 0.5 f = 2 Hz f = 2 Hz -1.0 0.0 0.5 1.0 1.5 2.0 t 0.5 f = 3 Hz f = 3 Hz -1.0 0.0 0.5 1.0 1.5 2.0 t 0.5 f = 4 Hz f = 4 Hz -1.0 0.0 0.5 1.0 1.5 2.0 t

LINGUIST 197M, SPRING 2018. CLASS 5.1 32 SPECTRUM OF COMPLEX WAVEFORM Amplitude (dB) 20 Amplitude (dB) 15 wave.complex 10 5 1 0 0.0 0.5 1.0 1.5 2.0 1 2 3 4 t Time (s) Frequency (Hz)

LINGUIST 197M, SPRING 2018. CLASS 5.1 33 SPECTRUM OF COMPLEX WAVEFORM Amplitude (dB) 20 Amplitude (dB) 15 Waveform: x-axis is time wave.complex 10 Spectrum: x-axis is frequency 5 1 0 0.0 0.5 1.0 1.5 2.0 1 2 3 4 t Time (s) Frequency (Hz)

LINGUIST 197M, SPRING 2018. CLASS 5.1 34 FROM SPECTRUM TO SPECTROGRAM: STEP 1 Amplitude (dB) Rotate clockwise Amplitude (dB) 3 4 1 2 4 1 2 3 4 3 Freq (Hz) 2 1 1 2 3 4 Freq (Hz)

LINGUIST 197M, SPRING 2018. CLASS 5.1 35 FROM SPECTRUM TO SPECTROGRAM: STEP 2 Amplitude (dB) Frequency (Hz) 2 3 4 1 1 2 3 4 1 2 3 4 Freq (Hz) Flip vertically 1 2 3 4 Amplitude (dB)

LINGUIST 197M, SPRING 2018. CLASS 5.1 36 FROM SPECTRUM TO SPECTROGRAM: STEP 3 Encode amplitude Frequency (Hz) levels (the height/ 1 2 3 4 length of the blue spikes) in grayscale* 1 2 3 4 1 2 3 4 *or with heat map Amplitude (dB)

LINGUIST 197M, SPRING 2018. CLASS 5.1 37 FROM SPECTRUM TO SPECTROGRAM: STEP 4 Encode amplitudes in grayscale… Frequency (Hz) 1 2 3 4 Frequency (Hz) 1 2 3 4 1 2 3 4 …at time t 1 Amplitude (dB)

LINGUIST 197M, SPRING 2018. CLASS 5.1 38 FROM SPECTRUM TO SPECTROGRAM: STEP 5 Line up spectral slices taken over time… Frequency (Hz) 1 2 3 4 t 1 t 2 t 3 t 4 t 5 t 6

LINGUIST 197M, SPRING 2018. CLASS 5.1 39 FROM SPECTRUM TO SPECTROGRAM: FINIS …and you have a spectrogram 5000 Frequency (Hz) 0 0.8772 1.128 Time (s)

40 MUSICAL INSTRUMENTS AND TIMBRE

LINGUIST 197M, SPRING 2018. CLASS 5.1 41 RECORDINGS OF INSTRUMENTS IN PRAAT Homework: bring in a musical instrument Thursday! Let’s do some recordings of your musical instruments in Praat!

LINGUIST 197M, SPRING 2018. CLASS 5.1 42 REAL-TIME OSCILLOSCOPE http://academo.org/demos/virtual-oscilloscope/

LINGUIST 197M, SPRING 2018. CLASS 5.1 43 REAL-TIME SPECTRUM ANALYZER http://academo.org/demos/spectrum-analyzer/

LINGUIST 197M, SPRING 2018. CLASS 5.1 44 REAL-TIME SPECTRUM ANALYZER II http://musiclab.chromeexperiments.com/Spectrogram