The Scrubber is a general controller for friction-induced sound. Allowing the user to engage in familiar gestures and feeling actual friction, the synthesized sound gains an evocative nature for the performer and a meaningful relationship between gesture and sound for the audience. It can control a variety of sound synthesis algorithms of which we demonstrate examples based on granular synthesis, wave-table synthesis and physically informed modeling. 1.

This paper discusses numerical experiments of wave front propagation on a flat disk and related results. In particular, notions of extremal rays and wave front caustics are introduced to investigate the dynamic behaviors of wave fronts under repeated reflection. These results are related to earlier work on caustics of ray systems. It is shown that wave fronts require a modified notion of caustic when considered under repeated reflection. We observe specific conditions for formation and annihilation of cusp singularities, self-tangencies and self-intersection of wave fronts.

Phya is an open source C++ library that facilitates physically motivated audio in virtual environments. A review is presented and recent developments in the context of game audio, including the launch of VFoley, a project using Phya as the basis for a fully fledged virtual sound design environment. This will enable sound designers to rapidly produce rich Foley content from within a virtual environment, and author enhanced objects for use by Phya enabled applications. 1.

We present case studies of unusual instruments that share the same excitation mechanism as that of the bowed string. The musical saw, Tibetan singing bow, glass harmonica, and bowed cymbal all produce sound by rubbing a hard object on the surface of the instrument. For each, we discuss the design of its physical model and present a means for expressively controlling it. Finally, we propose a new kind of generalized friction controller to be used in all these examples.

Abstract. This paper discusses aspects of topology as relevant for loop dynamics as they occur in physical modeling synthesis algorithms. Boundary and interaction point behavior is treated purely from a topological perspective for some dynamical systems in one and two dimensions. 1

rdmg dmu.ac.uk Phya is an open source C++ library originally designed for adding physically modeled contact sounds into computer game environments equipped with physics engines. We review some aspects of this system, and also consider it from the purely aesthetic perspective of musical expression.

The dynamics of drums can be described by wavefronts and their wake on a bundle of rays. Using the ray picture in their construction preserves the structure of the wave propagation, which in general is dispersed by traditional meshed methods. The idea is based on emphasizing local dynamical descriptions and impulse responses of continuous solutions in the plane and translating these properties into a computational model.

We propose iterating the fundamental solution of the 2-D wave equation to achieve a simulation of sections of a circular drum-head. The main advantage of this approach is the structural preservation of all features of the fundamental solution. The method uses the time-domain, hence displaying both stationary as well as evolutionary behavior immediately and is intended to be the conceptual 2-D analogue case of 1-D McIntyre-Schumacher-Woodhouse or waveguide-type time-domain simulations. These also preserve the structure of the fundamental solution, which in the 1-D case corresponds to traveling impulses and steps. Simulations show the form and scale of the well-known wake following disturbances of an initial excitation, but also further, rarely discussed features like a decaying residue in the neighborhood of a displacement excitation singularity which do not occur near velocity excitations. The method solely relies on evaluation of functions and features of the solution can be resolved up to numerical precision. The method is generalizable to any domain-shape with known reflection behavior but is not computationally efficient. The performance degrades linearly with the order of reflections and hence this method in its current form is not useful for long-time simulation of excitations or real-time sound synthesis.

A system is described for simulating environmental sound in interactive virtual worlds, using the physical state of objects as control parameters. It contains a unified framework for integration with physics simulation engines, and synthesis algorithms that are tailored to work within the framework. A range of behaviours can be simulated, including diffuse and non-linear resonators, and loose surfaces. The overall aim has been to produce a flexible and practical system with intuitive controls that will appeal to sound design professionals. This could be valuable for computer game design, and in other areas where realistic environmental audio is required. A review of previous work is included, and discussion of the issues which influence the overall design of the system.