Download Large-scale Real-time Modular Physical Modeling Sound Synthesis Due to recent increases in computational power, physical modeling synthesis is now possible in real time even for relatively complex models. We present here a modular physical modeling instrument design, intended as a construction framework for string- and bar- based instruments, alongside a mechanical network allowing for arbitrary nonlinear interconnection. When multiple nonlinearities are present in a feedback setting, there are two major concerns. One is ensuring numerical stability, which can be approached using an energy-based framework. The other is coping with the computational cost associated with nonlinear solvers—standard iterative methods, such as Newton-Raphson, quickly become a computational bottleneck. Here, such iterative methods are sidestepped using an alternative energy conserving method, allowing for great reduction in computational expense or, alternatively, to real-time performance for very large-scale nonlinear physical modeling synthesis. Simulation and benchmarking results are presented.
Download Simplified Guitar Bridge Model for the Displacement Wave Representation in Digital Waveguides In this paper, we present a simplified model for the string-bridge interaction in guitars or other string instruments simulated by digital waveguides. The bridge model is devised for the displacement wave representation in order to be integrated with other models for string interactions with the player and with other parts of the instrument, whose simulation and implementation is easier in this representation. The model is based on a multiplierless scattering matrix representing the string-bridge interaction. Although not completely physically inspired, we show that this junction is sufficiently general to accommodate a variety of transfer functions under the sole requirement of passivity and avoids integration constants mismatch when the bridge is in turn modeled by a digital waveguide. The model is completed with simple methods to introduce horizontal and vertical polarizations of the string displacement and sympathetic vibrations of other strings. The aim of this paper is not to provide the most general methods for sound synthesis of guitar but, rather, to point at low computational cost and scalable solutions suitable for real-time implementations where the synthesizer is running together with several other audio applications.
Download Live Convolution with Time-variant Impulse Response This paper describes a method for doing convolution of two live signals, without the need to load a time-invariant impulse response (IR) prior to the convolution process. The method is based on stepwise replacement of the IR in a continuously running convolution process. It was developed in the context of creative live electronic music performance, but can be applied to more traditional use cases for convolution as well. The process allows parametrization of the convolution parameters, by way of real-time transformations of the IR, and as such can be used to build parametric convolution effects for audio mixing and spatialization as well.
Download Filtering within the Framework of Mass-Interaction Physical Modeling and of Haptic Gestural Interaction A variety of filters have been designed, synthesized and used in the history of electronic and computer music. All the approaches aimed to provide filters fulfilling several specifications such as frequency response, phase response, transient state characteristics like rise time and overshoot, realizably conditions concerning the technology used for the implementation and even economical considerations. One of the most important aspects concerning the filters dedicated to musical applications is the control structure they provide to the musician, who is in charge for the integration of the filtering operation in the compositional process and performance. Designing filters using the mass interaction scheme embedded in the CORDIS-ANIMA formalism (used for sound synthesis and composition by physical modelling) offers a different methodology in the control which is coherent with the philosophy of musical composition by ‘physical thinking’. This article introduces a technique to design filters using the CORDIS-ANIMA simulation language.
Download Reverberation still in business: Thickening and Propagating micro-textures in physics-based sound modeling Artificial reverberation is usually introduced, as a digital audio effect, to give a sense of enclosing architectural space. In this paper we argue about the effectiveness and usefulness of diffusive reverberators in physically-inspired sound synthesis. Examples are given for the synthesis of textural sounds, as they emerge from solid mechanical interactions, as well as from aerodynamic and liquid phenomena.
Download Real-time Finite Difference Physical Models of Musical Instruments on a Field Programmable Gate Array (FPGA) Real-time sound synthesis of musical instruments based on solving differential equations is of great interest in Musical Acoustics especially in terms of linking geometry features of musical instruments to sound features. A major restriction of accurate physical models is the computational effort. One could state that the calculation cost is directly linked to the geometrical and material accuracy of a physical model and so to the validity of the results. This work presents a methodology for implementing realtime models of whole instrument geometries modelled with the Finite Differences Method (FDM) on a Field Programmable Gate Array (FPGA), a device capable of massively parallel computations. Examples of three real-time musical instrument implementations are given, a Banjo, a Violin and a Chinese Ruan.