Download Extensions and Applications of Modal Dispersive Filters Dispersive delay and comb filters, implemented as a parallel sum of high-Q mode filters tuned to provide a desired frequency-dependent delay characteristic, have advantages over dispersive filters that are implemented using cascade or frequency-domain architectures. Here we present techniques for designing the modal filter parameters for music and audio applications. Through examples, we show that this parallel structure is conducive to interactive and time-varying modifications, and we introduce extensions to the basic model.
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/
Download The Feathered Clarinet Reed In this research, a method previously In this research, a method previouslyapplied appliedtotoimprove improve a digital simulation of the avian syrinx is adapted to the geometry of the clarinet reed. The clarinet model is studied with particular attention to the case when the reed beats again the lay of the mouthpiece, closing off air flow to the bore once each period. In place of the standard reed table which gives steady-state volume flow as a function of constant pressure difference across the reed, a more realistic dynamic volume flow model is proposed. The differential equation governing volume flow dynamics is seen to have a singularity at the point of reed closure, where both the volume flow and reed channel area become zero. The feathered clarinet reed refers to the method, first used in the syrinx, to smooth or feather the volume flow cutoff in a closing valve. The feathered valve eliminates the singularity and reduces artifacts in the simulated clarinet output.