Download Considerations on window switching with the biorthogonal modulated lapped transform
The modulated lapped transform (MLT) can be regarded as the fundamental transform in the field of audio coding. The MLT is, however, an orthogonal tranform, which poses the limitation of the synthesis transform matrix being simply the transpose of the analysis transform matrix. This requires the analysis and synthesis window functions to be the same. It is possible to generalize the MLT into the biorthogonal modulated lapped transform (BMLT), and gain more flexibility in the choice of the analysis and synthesis window functions. It is further possible to adapt the BMLT window functions for example to tune the energy compaction of the analysis transform. This paper addresses the requirements of perfect reconstruction when the BMLT transform windows are varied in time.
Download Methods for modeling realistic playing in plucked-string synthesis: analysis, control and synthesis
Download Realtime-stretching of speech signals
Download Spectral data management tools for additive synthesis
This paper describes a set of procedures, named Toolbox, for spectral data reduction to be used in additive synthesis system based on sinusoidal model. The Toolbox has been developed in MATLAB with the specific aim to support the realization of a very large scale additive synthesis system (AddSynth) based on special purpose VLSI chips. Test signals and musical tones played by real acoustic instruments, in different conditions of execution: intensity, pitch etc, are considered. The Toolbox mainly performs spectral envelope data extraction, data reduction, spectral interpolation and produces proper data block set for both the AddSynth machine and the related software simulator.
Download Interpolated and warped 2-D digital waveguide mesh algorithms
Download A multirate, finite-width, bow-string interaction model
In this paper we propose an efficient method to model the amount of bow hair in contact with the string in a physical model of a bowed string instrument.
Download 2-D digital waveguide mesh topologies in room acoustics modelling
Digital waveguide mesh models have provided an accurate and efficient method of modelling the properties of many resonant structures, including acoustic spaces. 2-D rectilinear and triangular mesh structures have been used extensively in the past to model plates and membranes and are presented here as potential analogues to 2-D acoustic spaces. Impulse response measurements are taken and comparisons are made regarding the spectral content and the associated properties when compared with standard room acoustic parameters. Enhanced mesh structures are examined using frequency warping techniques and high-resolution sampling rates. The 2-D triangular mesh is shown to be considerably superior to the rectilinear mesh in terms of the measurements taken, with a further significant improvement being made by using the same mesh oversampled to a much higher resolution to improve the bandwidth of the measured impulse responses.
Download Physical models synthesis: balance between realism and computing speed
Download Full mesh warping techniques
This paper discusses methods for the elimination of dispersion in a digital waveguide mesh. As in previous methods, a highly isotropic waveguide mesh is chosen as a starting point, reducing the problem to compensation of frequency-dependent dispersion. For this purpose, as an alternative to Savioja and Välimäki’s technique of frequency-warping the input/output signals, we propose (1) inhomogeneous allpass-warping of delay elements, which enables use of allpass filters without introducing delay-free loops, and (2) “mass loading” the mesh in such a way that high-frequency propagation speed is increased to partially compensate dispersion due to quantization over a grid.
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.