Physics-Based Sound Synthesis for Games and Interactive Systems

This course introduces the basics of Digital Signal Processing and computational acoustics, motivated by the vibrational physics of real-world objects and systems. We will build from a simple mass-spring and pendulum to demonstrate oscillation, learn how to simulate those systems in the computer, and also prove that these simple oscillations behave as a sine wave. From that we move to plucked strings and struck bars, showing both solutions as combined traveling waves and combined sine wave harmonics. We continue to build and simulate more complex systems containing many vibrating objects and resonators (stringed instruments, drum, plate), and also learn how to simulate echos and room reverberation. Through this process, we will learn about digital signals, filters, oscillators, harmonics, spectral analysis, linear and non-linear systems, particle models, and all the necessary building blocks to synthesize essentially any sound. The free open-source software provided will make it possible for anyone to use physical models in their art-making, game or movie sound, or any other application.

• Digital Filters, Modal Synthesis
• a) Digital Filters, Finite Impulse Response (FIR) b) Linearity, Time-invariance, Convolution c) Infinite Impulse Response (IIR) Digital Filters d) BiQuad Resonator Filter, Modal Synthesis
• Physics, Oscillators, Sines & Spectra, Spectral/Additive Synthesis
• a) Mass-Spring-Damper system, also simple Pendulum b) Fourier analysis/synthesis, Spectrum Analysis 1.0 c) More on additive Sine-wave synthesis
• Tying it All Together: Applications, Sonification, Interactions, and Control
• a) Scanned Synthesis b)  Don’t forget the laptop!!! SMELT:   c) Controlling Synthesis with game controllers (Wii, mobile TouchOSC, more) d) Walking Synthesis, a complete system e) Procedural Audio: Driving synthesis from process, game state, etc. f) Data set Sonification
• Physical Modeling Synthesis: 1D systems
• a) 1-D systems, Strings, Modal (Fourier) Solution b) Strings II: Waveguide (D’Alembert) Solution c) 1-D systems, Bars, Tubes, solutions d) Advanced Waveguide Synthesis for 1-D systems
• The Time Domain: Sound, Digital Audio, PCM files, Noise vs. Pitch, a Hint of Spectra
• a) Sound in Air, Traveling Waves b) Digital Audio, Sampling, Quantization, Aliasing c) Soundfiles, Wavetables, Manipulating PCM d) Pitch (vs. Noise), Spectral Analysis 0.1 e) Time-domain Pitch/Noise Detection: ZeroXings, AMDF, Autocorrelation
• Grains, Particles and Statistical Models
• a) Wavelets b) Granular Synthesis c) Particle Models, Statistical Modal Synthesis d) Wind, Water, Surf, and Other Whooshing Sounds
• Subtractive Synthesis, Vocal Sounds and Models
• a)  Subtractive Synthesis, Voice Synthesis, Formants b) Linear Prediction, LPC c) FOFs d) FM Synthesis: Horns, Bells, Voices
• Extending and Refining Physical Synthesis Models
• a) Waveshaping Synthesis, Distortion Modeling b) Time-Varying Systems c) Stiffness, All-Pass Filters, Banded Waveguides d) Commuted Synthesis e) JULIUS on KS, strings, demos
• Physical Modeling II: 2 and 3-D Systems
• a) 2-D systems, plates, drums, higher-order modes Fourier (Sine and/or Modal) Solutions, Waveguide Solutions b) 3-D systems, rooms, resonators, Meshes, Waveguides c) Resonator/Modal view and solution of 3-D systems Pop bottles and other lumped resonators