Medialogy Group

This article describes banded waveguides, a way of synthesizing sounds made by solid objects and an alternative method for treating two- and three-dimensional objects. It belongs to the synthesis algorithms known as physical models, and in par-ticular, it is a departure from waveguide synthesis. Physical modeling of musical instruments is a synthesis technique that is well established in computer music. Physical models are historically related to computationally expensive algorithms (Ruiz 1969) but have become more efficient with faster methods such as waveguide synthesis (Smith 2003). Digital waveguide models provide discrete-time models of distributed media such as vibrating strings, bores, horns, and plates. We begin by outlining related synthesis methods with emphasis on traditional waveguide synthesis, which motivated the creation of this new struc-ture. To simulate sustained and transient excita-tions such as striking, bowing, and rubbing, different excitation models are also proposed in this article. Instruments that have been modeled using banded waveguides are discussed in a com-panion article (Essl et al. 2003). Digital Waveguides Figure 1 shows a one-dimensional digital wave-guide. A lossless digital waveguide is a bidirec-tional delay line at some wave impedance, and each delay line element contains a sampled traveling-wave component (Smith 2003). Efficient physical models of vibrating strings, wind instruments, and other quasi-harmonic sys-tems have been implemented using digital wave-guides. For a review of physical models using digital waveguides, see Smith (2003) and the refer-ences therein