Computer Sound Synthesis 2

MUS_TECH 335 Selected Topics

Physical Modeling Synthesis

Flute vs ClarinetWaveguides

The flute is a pipe open on both ends and it supports vibration at integer multiples of a fundamental frequency.

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Physical Model of a Flute:

Waveguides

Refined Waveguide Flute

Waveguides

Physical Model of the Voice

Vocal system is modeled in its many component parts. This creates a large number of physical parameters to specify.

Waveguides

Voice

Vocal tract seen as varying cross-section tube driven by glottal pulses. The waveguide concept is extended to a series of sections of short length.

Waveguides

Vowel formants are created by adjusting the width of the vocal tract in the physical model. Nasals (m,n) are produced by opening up the acoustical path to the nasal passage.

Waveguides

Lip and nasal systems are themselves modeled with waveguides.

Waveguides

Complete model is extended to include glotal sound source, fricative and aspiration noise sources, local filtering, etc.

Waveguides

SPASM package GUI has a huge number of controls. Controlled changes in the controls have to be synchronized.

Waveguides

WaveguidesFor all of the systems we have discussed so far, it can be assumed

that sound travels at a constant speed within the medium. This assumption breaks down for solid objects like those of wood or metal. In bars the speed of logitudinal waves is frequency dependent. The effect on transverse vibration has a similar effect.

WaveguidesIn delay-based modeling like Karplus-Strong and waveguides, this

can be simulated by putting all-pass filters in series with the delay. These all-pass filters cause there to be a frequency-dependent delay. Rather than use an all-pass comb filter, a large number of first-order all-pass filters are used.

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