The theme for this issue of Organised Sound is the Time Domain - a fundamental concern for composers, artists and engineers working with the musical application of technology. The range of material encompassed by this theme is vast. In fact many would say that it is impossible to divorce any aspect of musical work from its existence within the time domain. Consequently, time is likely to be the focus of future articles in Organised Sound.

Physical modelling of musical instruments is an exciting new paradigm in digital sound synthesis. The basic idea is to imitate the sound production mechanism of an acoustic musical instrument using a computer program. The sound produced by such a model will automatically resemble that of the real instrument, if the model has been devised in a proper way. In this article we review the history and present techniques of physical modelling. It appears that the many seemingly very different modelling methods try to achieve the same result: to simulate the solutions of the wave equation in a simplified manner. We concentrate on the digital waveguide modelling technique which has gained much popularity among both researchers and engineers in the music technology industry. The benefits and drawbacks of the new technology are considered, and concurrent research topics are discussed. The physical modelling approach offers many new applications, especially in the fields of multimedia and virtual reality.

This article discusses the nature of transcontextual references to time in the light of one composition, Kaija Saariaho's radiophonic work Stilleben. The term transcontextuality indicates that a sound has a dual meaning, which refers both to the musical context created by the composer and to its original, natural or cultural context. The concept of transcontextuality is particularly rewarding because a substantial part of Stilleben's sound material is drawn from an earlier composition by Saariaho, Lichtbogen. The focus of the study is in defining the ways the composition refers to time outside of the musical time of Stilleben itself. These references are divided into two categories: (i) references to the musical time of Lichtbogen, and (ii) references to the passage of time in a non-musical context. The first category leads to a music analytical approach where dominance/subordination relations of the time structures of the two compositions in question are studied. It is concluded that the temporal structure of Stilleben is defined by the temporality of Lichtbogen on various structural levels. The second category gives rise to reasoning with respect to narrative interpretation: environmental sounds convey stories and thus refer directly to the passage of time.

The use of video as a performance medium, concentrating on interactive digital video used synchronously with realtime interactive audio, is outlined. Specifically, the author's experiments with realtime video in Macromind Director and in Opcode's Max are explored, working with motion-sensing systems in performance environments. A number of experimental pieces using sonic and visual environments driven by realtime motion-sensing performance systems are described, using Max to re-map incoming sensing data and using Macromind Director to control MIDI sequences, digital sound files, and digital video in realtime. Some of the compositional challenges presented by realtime systems are also explored, particularly the compositional issues arising from the addition of video into the (real)time domain. The author's current work in the development of a CD-ROM published in 1996 is also explored. The CD-ROM attempts to provide a genuine degree of interaction significantly more sophisticated than the usual point-and-click navigation, allowing the viewer a degree of creativity in his or her interaction with the material.

Many software packages for computer music encourage the composer to take either a time domain approach or a frequency domain approach. This paper examines the possibilities afforded by recent software developments of working at the intersection of these two domains. It investigates the relationship between the FOF algorithm, originally used in the CHANT program, and more traditional approaches to granular synthesis, and considers how they can be combined. The author's compositions are used as illustrations of these techniques. The significance of using the FOF algorithm in granulating sound files is explained (FOG). Methods of using and controlling the FOG unit-generator are explained. Compositional and aesthetic issues arising from working with sound at this ambiguous intersection are investigated.

The purpose of Discovery Strategy is to define compositional methods which can lead first-time listeners to the musical substance of an electroacoustic work. Discovery Strategy provides a steering mechanism which directs first-time listeners towards identifying features that lie beneath the surface of the music. A key component of this mechanism is the skilful integration of familiar sounds into more abstract contexts. The implementation of the strategy rests on a consideration of how different listeners perceive music through time, and how their perception changes over repeated listenings. The tape work Undercurrents (Field 1994) follows these principles, demonstrating that it is not necessary to compromise structural sophistication while pursuing Discovery Strategy methods.

The design and construction of an organised sound space to support information representations in the human–computer interface is described. The design of the sound space is guided by four principles which match perceptual structure with data structure to improve natural comprehension of an auditory display. These principles – completeness, comprehensibility, consistency, and cohesiveness – have been generalised from the use of colour displays in scientific visualisation. The choice of perceptual parameters to represent different types of data is informed by the body of psychoacoustic literature. The raw material for the construction of the sound space is the McGill University Master Samples (MUMS) palette of musical instrument samples. This is an important choice because this reference resource enables reproduction and confirmation of the results. The construction was carried out in four stages – the ‘pedestal’, the ‘skin’, the ‘skeleton’ and the ‘flesh’. The pedestal consists of eight equally discriminable timbres organised in a circle by perceptual similarity. The skin is the boundary of variation in the space, defining the limits of dynamic range for pitch and brightness at each timbre. The skeleton characterises the internal behaviour of the space at a number of perceptually measured points. The flesh is a continuous medium moulded to the skeleton and skin, realised by a three-dimensional (3D) regularised linear spline interpolation. The concrete realisation of the sound space can be investigated through a user interface, called the GamutExplorer. Colour visualisations of slices and wireframe views of the 3D space can be chosen, and sounds can be picked with a mouse.

The annual Organised Sound CD will contain the following pieces and musical examples from Volume 1, Number 2:

Musical examples accompanying 'An introduction to Discovery Strategy' by Ambrose Field:

Musical example 1. Undercurrents, transformation from train to sea with textual thinning.

Musical example 2. Undercurrents, opening attacks and resonances.

Undercurrents for electroacoustic tape, complete work.