When some months before publication of the first issue of Organised Sound, Iannis Xenakis sent the editors a previously unpublished set of lecture notes for possible inclusion in the journal, it seemed natural to locate the resulting article within the present issue, whose major theme is 'algorithmic composition' (AC). Whilst Xenakis himself does not use this term, it is evident that he has had a major influence on those who do, as evidenced by his citations in most of the other articles in this issue. Not only has Xenakis been an original thinker in this domain, his article as presented here also illuminates many of his compositional practices, indicated as the working-out of probabilistic formulae. The article ranges wildely, with a section on the UPIC system, and we believe it also captures much of the empathetic, intensely enquiring nature of a mind deeply versed in both scientific and artistic modes of humanist thought.

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.

'Organised sound' - the term coined by Edgard Varèse for a new definition of musical constructivism - denotes for our increasingly technologically dominated culture an urge towards the recognition of the human impulse behind the 'system'. Such is the diversity of activity in today's computer music, we need to maintain a balance between technological advances and musically creative and scholarly endeavour, at all levels of an essentially educative process. The model of 'life-long learning' makes a special kind of sense when we can explore our musical creativity in partnership with the computer, a machine now capable of sophisticated response from a humanly embedded intelligence.

The Editors are delighted to welcome this contribution from a venerable pioneer of algorithmic composition who is also a member of Organised Sound’s Advisory Board. In this article, edited from notes for a series of lectures delivered in Poland, and not previously published, Xenakis tackles first the questions arising from determinacy and indeterminacy, repetition and variation, symmetry and structure, and multidimensional musical space. He later describes his computer drawing interface, UPIC, and ends with a discussion of some of his statistical compositional methods employing a variety of probability distributions. Much of the article is illuminated by insights drawn from a lifetime’s work in the arts and sciences.

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.

Since the mid-1980s commercial digital samplers have become widespread. The idea of musical instruments which have no sounds of their own is, however, much older, not just in the form of analogue samplers like the Mellotron, but in ancient myths and legends from China and elsewhere. This history of both digital and analogue samplers relates the latter to the early musique concrète of Pierre Schaeffer and others, and also describes a variety of one-off systems devised by composers and performers.

There are two distinct types of creativity: the flash out of the blue (inspiration? genius?), and the process of incremental revisions (hard work). Not only are we years away from modelling the former, we do not even begin to understand it. The latter is algorithmic in nature and has been modelled in many systems both musical and non-musical. Algorithmic composition is as old as music composition. It is often considered a cheat, a way out when the composer needs material and/or inspiration. It can also be thought of as a compositional tool that simply makes the composer’s work go faster. This article makes a case for algorithmic composition as such a tool. The ‘hard work’ type of creativity often involves trying many different combinations and choosing one over the others. It seems natural to express this iterative task as a computer algorithm. The implementation issues can be reduced to two components: how to understand one’s own creative process well enough to reproduce it as an algorithm, and how to program a computer to differentiate between ‘good’ and ‘bad’ music. The philosophical issues reduce to the question who or what is responsible for the music produced?

Within the context of discussing contemporary music the European tendency to overvalue abstraction is questioned. The use of environmental sounds in electroacoustic music is highlighted as an example of the questionable value of abstraction. Attention is then focused on a recent Truax composition, Powers of Two (1995) as a work of electroacoustic music theatre. The historical musical and poetic references, as well as the sound sources adopted for the work, are discussed, and placed within the human framework of relationship embodied in the piece. A concluding section summarises the work as an attempt to create a contemporary myth from historical sources, and as a dramatic expression employing electroacoustic forces.

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.

This article approaches the definition of the important term 'acousmatic' by reference to its origins in the sound studios of the French National Radio. The links from France to Québec are outlined and the Québecois acousmatic school, largely based in Montreal, is introduced. Aspects of a typical piece are discussed, and the author is able to answer the title question positively.

Algorithmic composition and gambling, two activities associated (in the public mind) with the use of chance, are contrasted. Gambling is based on the concepts of winning and losing. Algorithmic composition is not, or should not be. Problems of mappings of information from one medium to another are considered, along with problems of reception for artworks made with these methods. In the end, the quality of attention given to an artwork may be more critical to its reception than any methods used to construct it. Mr. Yasser’s Piano, Tuning the Furniture of Chaos and Pi and the Square Root of Two, three recent algorithmic compositions by the author, are considered in the light of these thoughts.

This paper deals with the role of the composer in algorithmic music. This role departs from traditional models because of the way computers are used in the compositional process, particularly when signal processing techniques are being integrated with sophisticated formal models to generate musical compositions. We shall examine several types of ‘musical formalism’ in order to bring out the active role of the composer in the compositional process.

It is common to oppose formalist and referentialist approaches to music. However, in Francis Dhomont's work Points de fuite, these approaches appear complementary when we consider the relationship between sounds and sources. Adopting the analytical approach of the American theorist Leonard B. Meyer, we show how the syntactic flow of Points de fuite generates formal implications through the impact of tension and relaxation archetypes. The piece explores metaphors based upon recurrent anecdotal events – the recorded signifiers of the source. These extra-musical elements define the work's structure to such an extent that they eliminate the traditional gap between formalism and referentialism in music.

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.

This paper describes TAO, a system for sound synthesis by physical modelling based on a new technique called cellular sound synthesis (CSS). The system provides a general mechanism for constructing an infinite variety of virtual instruments, and does so by providing a virtual acoustic material, elastic in nature, whose physical characteristics can be fine-tuned to produce different timbres. A wide variety of sounds such as plucked, hit, bowed and scraped sounds can be produced, all having natural physical and spacial qualities. Some of the musical and philosophical issues considered to be most important during the design and development of the system are touched upon, and the main features of the system are explained with reference to practical examples. Advantages and disadvantages of the synthesis technique and the prototype system are discussed, together with suggestions for future improvements.

Pietro Grossi was the first pioneer of computer music in Italy. During his activities from 1961 to the 1980s he devoted much research to algorithmic composition. Grossi’s first experiments in this field are discussed, dealing particularly with three important phases of his work: initiating algorithmic composition at the S 2F M studio in Florence, writing digital programs at the CNUCE Institute in Pisa, and realising a musical algorithm by translating the curve designed by the mathematician Peano into a sonic form.

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.

It is rare to see music and technology being used in combination in therapy and special education. This article is an account of work in a special school as part of a festival of popular music. The style of the music was dance/rave. This was made accessible using a specialised range of MIDI devices to enable students with physical and learning disabilities to participate. There are many benefits to be derived from studying popular music. In special education this can help with physical coordination and social skills. Most important, young people with special needs are given access to youth cultures from which, traditionally, they have tended to be excluded.

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.