Download Using the waveguide mesh in modelling 3D resonators Most of the results found by several researchers, during these years, in physical modelling of two dimensional (2D) resonators by means of waveguide meshes, extend without too much difficulty to the three dimensional (3D) case. Important parameters such as the dispersion error, the spatial bandwidth, and the sampling efficiency, which characterize the behavior and the performance of a waveguide mesh, can be reformulated in the 3D case, giving the possibility to design mesh geometries supported by a consistent theory. A comparison between different geometries can be carried out in a theoretical context. Here, we emphasize the use of the waveguide meshes as efficient tools for the analysis of resonances in 3D resonators of various shapes. For this purpose, several mesh geometries have been implemented into an application running on a PC, provided with a graphical interface that allows an easy input of the parameters and a simple observation of the consequent system evolution and the output data. This application is especially expected to give information on the modes resonating in generic 3D shapes, where a theoretical prediction of the modal frequencies is hard to do.
Download Recognition Of Ellipsoids From Acoustic Cues Ideal three-dimensional resonators are “labeled” (identified) by infinite sequences of resonance modes, whose distribution depends on the resonator shape. We are investigating the ability of human beings to recognize these shapes by auditory spectral cues. Rather than focusing on a precise simulation of the resonator, we want to understand if the recognition takes place using simplified “cartoon” models, just providing the first resonances that identify a shape. In fact, such models can be easily translated into efficient algorithms for real-time sound synthesis in contexts of human-machine interaction, where the resonator shape and other rendering parameters can be interactively manipulated. This paper describes the method we have followed to come up with an application that, executed in real-time, can be used in listening tests of shape recognition and together with human-computer interfaces.
Download Recognition of Distance Cues from a Virtual Spatialization Model Emerging issues in the auditory display aim at increasing the usability of interfaces. In this paper we present a virtual resonating environment, which synthesizes distance cues by means of reverberation. We realize a model that recreates the acoustics inside a tube, applying a numerical scheme called Waveguide Mesh, and we present the psychophysical experiments we have conducted for validating the information about distance conveyed by the virtual environment.
Download Computation of Nonlinear Filter Networks Containing Delay-Free Paths A method for solving filter networks made of linear and nonlinear filters is presented. The method is valid independently of the presence of delay-free paths in the network, provided that the nonlinearities in the system respect certain (weak) hypotheses verified by a wide class of real components: in particular, that the contribution to the output due to the memory of the nonlinear blocks can be extracted from each nonlinearity separately. The method translates into a general procedure for computing the filter network, hence it can serve as a testbed for offline testing of complex audio systems and as a starting point toward further code optimizations aimed at achieving real time.