Winds

Woodwinds are sounding quite good in some cases, particularly on the Yamaha VL1 synthesizer which uses digital waveguide techniques [50,26,15]. Single-reed theory appears to be pretty well understood, although there are some outstanding questions regarding flow separation in the mouthpiece [27]. Double-reeds, on the other hand, such as the oboe and bassoon, are not yet fully understood theoretically, as evidenced by the fact that new theoretical models are still being proposed [79]. Nevertheless, it is generally acknowledged that the oboe and bassoon presets in the VL1 are excellent as far as they go.

Implementations of woodwind finger-hole models have recently been developed using fractional-delay filters [63] with coefficients based on both theoretical and experimental values from musical acoustics [38].

While the theory of air-jet driven instruments is perhaps the most slippery in all of musical acoustics, existing flute models nevertheless sound good and are highly expressive [15,33], including register shifting (``overblowing'') in response to modulation of the virtual ``jet delay.'' The VL1 shakuhachi patch is a good example of the present state of the art along these lines. Convincing flute models have also been constructed using purely lumped elements to model the bore [77,76]. In principle, discrete-time simulations of distributed systems can always be approximated to arbitrary precision using lumped modeling elements. (An example is the standard LC model of a transmission line, which corresponds to a mass-spring model of an acoustic waveguide.) Therefore, simple resonators are fully general building blocks for linear systems. However, the use of digital waveguides greatly reduces computational complexity and enables accurate nonlinear extensions [54].

Recorder-like instruments have recently been given a strong boost lately [71,72], including new applications of the theory of fluid dynamics. Marc-Pierre Verge has recently implemented a practical synthesis model at IRCAM based on his thesis work at Eindhoven [74].

Identification of acoustic tube parameters is a fairly classical subject in acoustics, but only recently have papers begun to appear on practical techniques for estimating the filters needed for digital waveguide models of wind instruments [48,36,58].