In a society filled with individuals claiming ownership of new ideas, it is surprising to note how modest the reaction was to our ‘call for papers’ for this issue, which was to be primarily based on the theme, ‘Breaking the Boundaries’. Perhaps this has to do with the number of people who believe that the new millennium will commence in January 2001. We have chosen two submissions to include in Volume 4(3) of Organised Sound. Barry Truax presents his thoughts on the current position of the electroacoustic community in the form of a letter to a twenty-five year old electroacoustic composer which highlights paradigm shifts that he sees evolving. Laurie Spiegel's ‘Music as mirror of mind’ describes another paradigm shift towards new musical models based on psychoacoustics, cognitive studies and subjective auditory experience.

For the first time, an issue of Organised Sound has been published without a theme. This has been done, not due to the Editors' running out of appropriate ideas, but instead to allow us to publish a number of submitted manuscripts that would have had to be placed in a queue if we had not dedicated one issue to catching up. In fact, the notion of a themeless issue is not completely correct. Of the six articles published in this issue, one falls reasonably well within our recent theme on space (Drever) due to the author's interest in soundscape; another two (Graves/Hand/Hugill and Manning, the issue's Tutorial Article) follow up our last issue's theme concerning image. My own contribution to this issue has been included to initiate a few of the debates associated with our thematic issue 4/3 concerning ‘Breaking the Boundaries’. I am pleased that we have two Student Articles in this issue (Couprie and Drever). The submissions that have no bearing on past or future issue themes are those by Couprie (analysis of electroacoustic music) and Polfreman (music composition software).

The main theme of this issue of Organised Sound is algorithmic compostion, one which we have featured before, and yet the flavour of the current issue is very different. It perhaps says something of the richness and the variety of the topic that it can elicit such different responses. Perhaps many of us are still not clear exactly what algorithmic composition is, and the vagueness of the definition itself contributes to a broad range of responses.

This paper postulates that the analysis of MIDI data allows for the statistical analysis of motion in music, in particular, the kinematic analysis of motion curves in music. The paper deals with the analysis of the kinematic motion components within music, specifically music velocity (i.e. tempo) and music acceleration/deceleration (i.e. tempo change), based upon Truslit's definition of the predominant up–down motion types in music (1938). Thus, the variables of music velocity and acceleration are mathematically defined and extracted from MIDI encodings. Analysis of music velocity indicates that the differing motion types have specific and consistent velocity profiles, and that these profiles can be expressed mathematically and analysed statistically. In particular, the paper focuses on the open motion curve fit, relating the open motion velocity curve to the beta distribution. Analysis of acceleration within music suggests that music acceleration is not constant in nature, implying that theories of linear velocity are inaccurate models. Hence, it is suggested that MIDI data analysis allows for the statistical exploration into music kinematics and the motion curves within music.

This article deals with the analysis of a work by François Bayle, L'oiseau moqueur (1963). I worked at the INA-GRM (Paris) in order to realise a graphic record of the piece using their proprietary acousmograph software. To work from this graphic record, I used three methods of analysis: identification and classification of sound objects using a Schaefferian typology, comparison of objects with one another following a paradigmatic approach, and presentation of the results obtained through enumeration of a certain number of values (duration, density of objects, etc.).

To begin with, I would like to cite the influence, both direct and indirect, of the following disciplines on my personal: research: philosophical reflection, linguistics and physics. I will do this briefly sketching the fusion of these disciplines, not strictly with my music and the role it plays as the foundation of a personal aesthetic.

This article describes the design and implementation of MidiVisualiser, a virtual environment which provides an interactive visualisation of MIDI music data. Section 1 explores music visualisation in general and examines the role of computers and virtual environments. Section 2 briefly surveys existing music visualisation research and places MidiVisualiser in context. Section 3 examines various techniques of visualisation and discusses composite dimensions and ‘Benediktine cyberspace’, including a description of how visualisation techniques derived from them were used in MidiVisualiser to overcome some of the difficulties associated with representing large numbers of data attributes simultaneously. Sections 4 and 5 contain an overview of the implementation and evaluation of MidiVisualiser, while section 6 discusses future work and conclusions.

So, this field we call electroacoustic music is celebrating its first half century, just as I did recently. While I cannot say that I actually grew up with this music, I discovered it in my early twenties (1969), and so I have participated in a good twenty-five years of its development. I have also heard a lot about the previous twenty-five years, often from the practitioners themselves, many of whom have unfortunately passed away in the meantime. With any luck I may still have another twenty-five years, and then you will be in my place now, and I wonder what choices you will have made, and what you will be writing to the next generation?

This paper outlines some of the technical and aesthetic issues arising from my works which involve computer technology directly in live performance. A process of experimentation in algorithmic composition is described, particularly in relation to aspects of form and ways of automating musical processes at various structural levels. Three works are then described: Kendhang is a work in which a dancer influences the output of a simple algorithmic music system based on interpolation; Or is an instrumental trio which uses realtime sound granulation; and Vug extends this realtime granulation and applies it to a solo clarinet line. An exploration of both the distinctions and similarities between these works is used to develop a general approach to the integration of computer-based algorithmic systems with live performance. This approach emphasises the need for efficient use of technological resources in order to convey expressive content accurately.

This paper describes the ideas and methods that led to the writing of an algorithmic composition NTrope Suite. This piece, for solo recorders and voice, was generated by ‘mixing’ works by different composers from different eras. The idea behind the work was to examine random generation procedures that could maintain stylistic properties typical to the reference works. The interesting property of this method is that it implements a sort of ‘statistical learning’, that optimally preserves the properties of the reference pieces and also properly ‘generalises’ them so as to create a new valid work. The musical result is very coherent, maintaining both stylistic resemblance to the reference music and exhibiting some surprising originality as well. Theoretically, the resulting piece is closest to the reference works in terms of mutual entropy. The algorithm and its theoretical significance are discussed in the paper.

Hierarchical and other historically dominant models of perceived musical organisation are increasingly inapplicable to new musical processes and repertoire. The next major paradigm shift for music models, structures and concepts, perhaps comparable in importance to that in which polyphony gave way to homophony, may be a shift of emphasis from means of acoustic production and the nature of sound per se to new musical models based on psychoacoustics, cognitive studies and subjective auditory experience.

As if the (terrified) Photographer must exert himself to the utmost to keep the Photograph from becoming Death. But I, already an object, I do not fight. (Barthes 1988: 14)

Perhaps this is the ultimate way of playing with reality. (Baudrillard 1997: 38)

Every day the urge grows stronger to get hold of an object at very close range by way of its likeness, its reproduction. (Benjamin 1992: 217)

This paper is born out of my experience as an electroacoustic composer/sound artist and consumer, who passionately engages in the procurance, employment and exchange of soundscape recordings: an ambivalent engagement which is aesthetically rewarding, yet on further reflection deeply unsettling. The aim of this paper is to question and explore why this ostensibly benign and increasingly common procedure (i.e. the routine of soundscape recording/sampling/abstracting, editing, retouching, transforming, mixing, recontextualising . . . ) may result in a durable confrontation with ‘terror’ accompanied by ethical compromise. To articulate a personal and intuitive response, I will refer to critical writings on photography to illuminate sound (i.e. utilising the photograph as a counterpoint to the sonic record). I will be focusing in particular on the recording and the reappropriation of human utterance in electro-acoustic music, as it is probably the most intimate, as well as familiar, sonic material to humans. You cannot escape from your own voice. ‘Soundscape’ denotes ‘any acoustic field of study’ (Schafer 1994: 7); however, in this context I wish to focus on acoustic fields which have a particular social or cultural significance.‘To photograph is to appropriate the thing photographed.’ (Sontag 1984: 4) Thus it is appropriated again when employed in sound art.

Music acoustics research can provide support in terms of objective knowledge to further the rapidly developing areas of music technology and audio processing. This is illustrated by three examples taken from current projects at KTH. One concerns the improvement in quality of sound reproduction systems over the last century. A test, where expert listeners rated the year of recordings of different ages, demonstrated that significant advances were made between 1950 and 1970, while development was rather modest before and after this period. The second example investigates the secrets of timbral beauty. Acoustic analyses of recordings of an international opera tenor and a singer with an extremely unpleasant voice shed some light on the basic requirements of good vocal timbre. The unpleasant voice is found to suffer from pressed phonation, lack of a singer's formant, irregular vibrato and insufficient pitch accuracy. The third example elucidates tuning and phrasing differences between deadpan performances of MIDI files played on synthesizers and performances by musicians on real instruments. The examples suggest that future development in the areas of music technology and audio processing may gain considerably from a close interaction with music acoustics research.

This paper presents an overview of a generic task model of music composition, developed as part of a research project investigating methods of improving user-interface designs for music software (in particular focusing on sound synthesis tools). The task model has been produced by applying recently developed task analysis techniques to the complex and creative task of music composition. The model itself describes the purely practical aspects of music composition, avoiding any attempt to include the aesthetic motivations and concerns of composers. We go on to illustrate the application of the task model to software design by describing various parts of Modalyser, a graphical user-interface program designed by the author for creating musical sounds with IRCAM's Modalys physical modelling synthesis software. The task model is not yet complete at all levels and requires further refinement, but is deemed to be sufficiently comprehensive to merit presentation here. Although developed for assisting in software design, the task model may be of wider interest to those concerned with the education of music composition and research into music composition generally. This paper has been developed from a short presentation given at the First Sonic Arts Network Conference in January 1998.

Palatal Sound is a model of vocal tract articulation influenced by physiologic and acoustic analysis of the voice. Specifically, the term articulation refers to all movement within the vocal tract that results in open, filter-like sonorities, as well as in turbulent to absolute airflow modification. This model presents a complete mapping of place within the vocal tract that features flexibility across different vocal tract sizes and proportions. The principles behind this comprehensive mapping of acoustic and physical sound production techniques should not be foreign to those persons who create, combine, design, model or research sound. Therefore, this model might suggest avenues of sound exploration regardless of media or application. This text first presents a brief overview of the current trends of oral modification using vowels, followed by an introduction to and acoustic analyses of the comprehensive vocal tract model as applied to open-like sonorities. This model is then expanded through the presentation of other methods of open-like behaviours. Following the discussion of open sonorities, turbulent-like behaviours are discussed by first identifying the use of language-based fricatives and stops. After this (re-)exposition, the comprehensive model is applied to turbulent structures through examples and acoustic analyses. Finally, these turbulent methods are completed by additional, complementary methods of vocal tract turbulence. The intentions of this paper are: (i) to document this model clearly, (ii) to identify differences between speech and song articulatory behaviour and that of this comprehensive model with the aid of selected acoustic analyses, (iii) to suggest that this model renders valuable scientific information about the limits of vocal tract physiology, and (iv) to propose the practical use of this model by composers and performers.

We present a novel efficient algorithm for scaling the frequency content of an audio signal by any desired factor in the range 0.5 (minus one octave) to 2.0 (plus one octave) enabling a recording to be played in any desired key without affecting the tempo. The algorithm uses an adaptive overlap-add (AOLA) technique to realise the desired frequency scaling without affecting the duration. Informal listening tests show output quality equal to that of a conventional overlap-add algorithm used in many commercially available systems, but offering significant computational saving relative to that algorithm. The algorithm can also be used to simultaneously change both the tempo and key of a recording.

KYKLOS, an algorithmic composition program, is presented here. It generalises musical scales for use in composition as well as in performance. The sonic output of the system is referred to as polymodal music since it consists of four independent voices playing ‘synthetic modes’. KYKLOS is suitable for computer-assisted composition because it generates MIDI files which can be altered later by the composer. It can equally well be used in live performance for dynamic modification of parameters enabling realtime musical control.

This article provides an insight into the history of interactive graphical control interfaces for computer-based and computer-assisted music applications and identifies a number of the challenges which currently face contemporary designers of new software and hardware tools in this context. By studying some of the key features of this rich and varied legacy, it is possible to establish some useful criteria to underpin the development of new and improved tools for manipulating visual representations of music data which can be as diverse as common music notation, acoustic spectra, and all manner of simulations modelling the physical control surfaces associated with devices such as commercial synthesizers and audio mixing consoles.

For a system to be able to generate realtime accompaniment to previously unknown songs, it must predict their harmonic development, i.e. the chords to be played. We claim that such a system must combine long-term experience, to identify typical chord sequences (e.g. II–V and II–V–I), with ‘on-the-fly’ adaptation to track-recurrent structures (e.g. choruses and refrains) of the particular song being played. We have implemented a prediction system using a neural network model that encompasses prior knowledge about typical chord sequences. The results achieved are very encouraging, and rather better than those reported in the literature. However, our predictor could not adapt its behaviour to the idiosyncrasies of each song, since online learning is difficult in neural networks. In this paper, we propose an extension to our previous work by the inclusion of a rule-based sequence tracker, which detects recurrent chord sequences while the song is being performed. We show that this hybrid model, which combines a neural network predictor with a rule-based sequence tracker, improves the system's performance.

Existing audio tools handle the increasing amount of computer audio data inadequately. The typical tape-recorder paradigm for audio interfaces is inflexible and time consuming, especially for large data sets. On the other hand, completely automatic audio analysis and annotation is impossible using current techniques. Alternative solutions are semi-automatic user interfaces that let users interact with sound in flexible ways based on content. This approach offers significant advantages over manual browsing, annotation and retrieval. Furthermore, it can be implemented using existing techniques for audio content analysis in restricted domains. This paper describes MARSYAS, a framework for experimenting, evaluating and integrating such techniques. As a test for the architecture, some recently proposed techniques have been implemented and tested. In addition, a new method for temporal segmentation based on audio texture is described. This method is combined with audio analysis techniques and used for hierarchical browsing, classification and annotation of audio files.