Download Dispersion modulation using allpass filters Dispersion is a physical phenomenon that makes sound waves more or less inharmonic. Most physical sound synthesis models consider dispersion as a constant property that does not change during the course of a musical event. However, these models would be more expressive without such a restriction. This paper describes a dispersion amount parameter for precise control over inharmonicity, and then experiments with control and audio rate modulation of that parameter. In this research we found that inharmonicity of a plucked string could be smoothly controlled in real-time, and that novel sonic material could be synthesized when the modulation rate was raised into audio range. Instability of the string model with certain parameter values was considered to be problematic.
Download Sound synthesis using an allpass filter chain with audio‐rate coefficient modulation This paper describes a sound synthesis technique that modulates the coefficients of allpass filter chains using audio-rate frequencies. It was found that modulating a single allpass filter section produces a feedback AM–like spectrum, and that its bandwidth is extended and further processed by non-sinusoidal FM when the sections are cascaded. The cascade length parameter provides dynamic bandwidth control to prevent upper range aliasing artifacts, and the amount of spectral content within that band can be controlled using a modulation index parameter. The technique is capable of synthesizing rich and evolving timbres, including those resembling classic virtual analog waveforms. It can also be used as an audio effect with pitch-tracked input sources. Software and sound examples are available at http://www.acoustics.hut.fi/publications/papers/dafx09-cm/