The soundscape composition is the journey that circumscribes the relationship, the conversation between composer and sound sources. (Hildegard Westerkamp)

Environmental sounds hold an unusual place in our imaginations. On the one hand, hey make up the often unnoticed ambiences of our daily lives: they are so much with us and surrounding us that it takes a special effort to bring them into the foreground, and pay attention to them. On the other hand, environmental sounds form a powerful conduit to memory. Hearing a particular sound or ambience can launch a chain of related memories, whether experienced consciously or working subconsciously, that reconnects us with particular places and times in our lives. It is precisely these confluences of memory, time and place that interest those who compose with soundscapes.

This issue of Organised Sound focuses on mapping in computer music. Unlike many issues of the journal, all articles in this edition are related to the theme. The call for contributions resulted in a significant collection of work which covered a broad range of activity in the field. This number of articles would normally fill more than one issue of the journal but we decided to keep the collection together as a representative body of work.

We were delighted to welcome Marcelo Wanderley as Guest Editor for this issue. I would like to thank him for his hard and diligent work throughout the preparation of this issue.

This issue of Organised Sound is about interactivity, a theme that the journal has often visited in the past. What makes this visit to this very important subject special is that it has been chosen as the first theme within our annual collaboration with the International Computer Music Association (ICMA). The ICMA President, Mary Simoni, has joined the Editors this year as ICMA representative and Mara Helmuth, currently the ICMA's editor of Array, has kindly taken on the role of Guest Editor for this issue. The journal Editors would like to welcome the ICMA and thank those ICMA members, and Mara in particular, who helped to make this issue possible. We look forward to further developing this collaborotion.

Software-based musical instruments have controls for input, a sound synthesizer for output, and mappings connecting the two. An effective layout of controls considers how many degrees of freedom each has, as well as the overhead of selecting each one while performing. An isolated mapping from one control to one synthesis parameter needs an appropriate choice of proportional, integral or derivative control (the control's value, or that value's rate of change, drives the synthesis parameter's value, or that value's rate of change). Beyond this, a compound mapping cross-coupling several controls and synthesis parameters can surprisingly increase the performer's intuitive understanding of the instrument.

The soundscape composition, as pioneered at Simon Fraser University since the early 1970s, has evolved rapidly to explore a full range of approaches from the ‘found sound’ representation of acoustic environments through to the incorporation of highly abstracted sonic transformations. The structural approaches similarly range from being analogues of real-world experience, such as listening from a fixed spatial perspective or moving through a connected series of acoustic spaces, to those that mirror both nonlinear mental experiences of memory recall, dreams, and free association, as well as artificial sonic constructs made familiar and possible by modern ‘schizophonic’ audio techniques of sonic layering and embedding. The octophonic surround-sound playback format as used in contemporary soundscape presentations has achieved a remarkable sense of immersion in a recreated or imaginary sonic environment. Specific works realised at SFU are analysed that illustrate each of these approaches.

Pikapika is a collaborative solo performance by Bahn and Hahn that presents a simple model of composition, choreography and collaboration in an interactive context. The piece offers the possibility of a new kind of interactive theatre/costume design –an interactive sonic character. This essay is a case study of a design process for interactive performance. While we include some details of our specific interface, these are primarily employed as examples to suggest our principles for creating personal, idiosyncratic interactive systems. Our collaboration integrates elemental sound and movement relationships with an awareness of the embodied cultural knowledge of the performer and with a specific sensing scheme to capture her particular gestural vocabulary. The combination of individual ‘atoms’ of movement and sound leads to a complexity that must be practised until they can be performed with ease as an embodied interaction. We find the process of collaboration and its articulation as a dynamic interactive structure fascinating and enduring beyond the specific technologies employed. The terms meta-composition, composed instrument and composed character are used to describe the interactive structure of the piece.

This paper considers the issues involved in the design of electronic and computer interfaces, specifically mapping - the designed link between an instrument's playing interface and its sound source. It defines the problem area, reviews the literature, and gives examples of specific system mappings. A general model is presented, with the aim of providing a framework for future discussions on what makes an effective mapping. Several guidelines for mapping strategies are given, based on existing work.

In contemporary music and arts practices the previously distinct roles of author, composer and performer have become increasingly conflated, catalysed by the use of computer technology. Newly combined roles of composer and performer that are assumed by one or more people or computer systems are identified and described, as well as actions including preparation, organisation and presentation. In this paper the interface is described as an ‘interactivated space’ to encompass both the intimate scale of a performer manipulating the materials through an on-body interface, and the larger in-space interface where the work is shared with the performers and audience. Two examples of projects the authors are involved in are described, which form the basis for further discussion. The two interfaces that manifest themselves in the processes, the instrument and the score are discussed in more detail with a focus on their changed appearance and role.

In discussing different sound environments - sound in the field of art as well as sound in the context of our daily sonic environment - this article makes reference to semiotic theories.

Sound without source. Electroacoustic media shape our perceptive realities. There are multiple tools available to record and reproduce sound, but is it possible to handle the fleeting nature of sound, the escape of sound? Certainly there are tools to manipulate sound, to create new soundscapes in this way. We can generate virtual sound-projecting soundscapes via speakers, via headphones in a new context - but what are we listening to?

Every sound evokes images. The concept of ‘musique acousmatique’, according to François Bayle, amplifies Pierre Schaeffer's notion of the ‘objet sonore’. ‘Musique acousmatique’ refers to sound projection, and thus to our imagination while concentrating on listening. In listening to acousmatic music, we can find three tonal levels, and this tripartite concept of listening refers to the tripartite semiotic concept introduced by Charles Sanders Peirce.

Finally, sound affects us emotionally. In contradiction to the term ‘objet sonore’, the term ‘sound event’ coined by R. Murray Schafer stresses the necessity to analyse sound in its context. It is the sonic environment which determines the meaning of the ‘sound event’. Thus, from my point of view, the concept of soundscape can be compared with Ferdinand de Saussure's semiotic theory about the arbitrary meaning of signs. Signs are determined by their systems.

Semiotic concepts offer an interesting approach to sound perception. Let's listen to soundscapes before sound escapes.

In the early 1930s, maverick composer Henry Cowell collaborated with inventor Leon Theremin to build an electronic instrument capable of producing intricate polyrhythms. This instrument, dubbed the Rhythmicon, can be considered a rudimentary example of an interactive music system. Cowell and Theremin created the machine to fulfil a compositional need, but it ultimately failed to become a successful musical instrument. The Rhythmicon was one of the first electronic music instruments to use technology to extend performers' musical capacities, anticipating the interactive computer music movement by several decades. Despite its shortcomings, the Rhythmicon should be remembered as an important step on the road to interactivity.

Despite roots in acoustic ecology and soundscape studies, the practice and study of soundscape composition is often grouped with, or has grown out of the acousmatic music tradition. This can be observed in the positioning of soundscape compositions juxtaposed with acousmatic music compositions in concert programmes, CD compilations and university syllabuses. Not only does this positioning inform how soundscape composition is listened to, but also how it is produced, sonically and philosophically. If the making and presenting of representations of environmental sound is of fundamental concern to the soundscape artist, then it must be addressed. As this methodological issue is outside of previous musical concerns, to this degree, we must look to other disciplines that are primarily engaged with the making of representation, and that have thoroughly questioned what it is to make and present representations in the world today. One such discipline is ethnography. After briefly charting the genesis of soundscape composition and its underlying principles and motivations, the rest of the paper will present and develop one perspective, that of considering soundscape composition as ethnography.

We define a two-axis transparency framework that can be used as a predictor of the expressivity of a musical device. One axis is the player's transparency scale, while the other is the audience's transparency scale. Through consideration of both traditional instruments and new technology-driven interfaces, we explore the role that metaphor plays in developing expressive devices. Metaphor depends on a literature, which forms the basis for making transparent device mappings. We examine four examples of systems that use metaphor: Iamascope, Sound Sculpting, MetaMuse and Glove-TalkII; and discuss implications on transparency and expressivity. We believe this theory provides a framework for design and evaluation of new human–machine and human–human interactions, including musical instruments.

Composing has been slighted at all levels of education. Following an analysis of the history and failure of compositional pedagogy for developing musicianship, a new rationale for such pedagogy is presented. This pedagogy is argued to be essential for preparing contemporary musicians and audiences to understand most properly what music ‘is’ and ‘is good for’, and for promoting ever-new conceptions of ‘music’ and of its evolving values. In addition to advancing general musicianship in relation to the standard repertory, the special contribution of pedagogy rooted in composing organised sound pieces is outlined in relation to a new praxial philosophy of music that is challenging the limited and limiting theory of music and its value provided by traditional aesthetic theory. The latter is seen to be a major impediment to new compositional modes that expand musical frontiers, while the praxial theory supports, as well as gains support from, various new attempts to organise sound for expressive and other purposes.

This paper is about mapping strategies between gesture data and synthesis model parameters by means of perceptual spaces. We define three layers in the mapping chain: from gesture data to gesture perceptual space, from sound perceptual space to synthesis model parameters, and between the two perceptual spaces. This approach makes the implementation highly modular. Both perceptual spaces are developed and depicted with their features. To get a simple mapping between the gesture perceptual subspace and the sound perceptual subspace, we need to focus our attention on the two other mappings. We explain the mapping types: explicit/implicit, static/dynamic. We also present the technical and aesthetical limits introduced by mapping. Some practical examples are given of the use of perceptual spaces in experiments done at LMA in a musical context. Finally, we discuss several implications of the mapping strategies: the influence of chosen mapping limits onto performers' virtuosity, and the incidence of mapping on the learning process with virtual instruments and on improvisation possibilities.

The expression gestural mapping is well imbedded in the language of instrument designers, describing the function from interface control parameters to synthesis control parameters. This function is in most cases implicitly assumed to be instantaneous, so that at any time its output depends only on its input at that time. Here more general functions are considered, in which the output depends on the history of input, especially functions that behave like physical dynamic systems, such as a damped resonator. Acoustic instruments are rich in dynamical behaviour. Introducing dynamics at the control stage of an electronic instrument can help compensate for lack of dynamics in later non-physical synthesis stages. A broadening of the function space offers new aesthetic possibilities for composing instruments. Examples are presented to illustrate the new design/composition mode as well as practical techniques. In this context, it is suggested that the word mapping be updated with the more descriptive expression dynamic control processing.

Hildegard Westerkamp's Kits Beach Soundwalk challenges us as listeners to re-evaluate our acoustic soundscape. Juxtaposing the sounds of barnacles with the noise of the city, Westerkamp reveals an unbalanced world in which individual voices are silenced. Kits Beach Soundwalk allows Westerkamp to help rectify that imbalance. It provides her with the opportunity to create a place in which a listener can take pleasure in simply being. She reveals the metaphors, the hidden entrances, within sounds that take us into other spaces. A listener travels with Westerkamp into worlds of tiny sounds and tiny voices, dreams, and places of fantasy and the imagination. She challenges us as listeners to re-establish our place within the world around us. By designing the piece to reach the audience on a number of levels - intellectual, physiological, metaphorical - Westerkamp effectively promotes the changing of listening habits; the distancing of individuals from oppressive sonic environments; and the regaining of an individual's inner voice.

This article collates results from a number of applications of interactive evolution as a sound designer's tool for exploring the parameter spaces of synthesis algorithms. Experiments consider reverberation algorithms, wavetable synthesis, synthesis of percussive sounds and an analytical solution of the stiff string. These projects share the property of being difficult to probe by trial and error sampling of the parameter space. Interactive evolution formed the guidance principle for what quickly proved a more effective search through the multitude of parameter settings.

The research was supported by building an interactive genetic algorithm library in the audio programming language SuperCollider. This library provided reusable code for the user interfaces and the underlying genetic algorithm itself, whilst preserving enough generality to support the framework of each individual investigation.

Whilst there is nothing new in the use of genetic algorithms in sound synthesis tasks, the experiments conducted here investigate new applications such as reverb design and an analytical stiff string model not previously encountered in the literature. Further, the focus of this work is now shifting more into algorithmic composition research, where the generative algorithms are less clear-cut than those of these experiments. Lessons learned from the deployment of interactive evolution in sound design problems are very useful as a reference for the extension of the problem set.

Mapping concerns the connection between gestures, or structures and audible results in a musical performance or composition. While this is of intense interest to performers of new instruments and instrument designers, it has also been an area of interest for some composers. Algorithmic composition is sometimes the process of imagining a gesture or structure - perhaps physical or visual - and then applying a mapping process to turn that ‘gesture’ of the conceptual domain into sound which may display the original conception in some way. This article looks at mapping from the point of view of algorithmic composition, particularly where persistence is an issue, such that the gesture (conceptual domain) is embodied and perceptible in the musical result.

This paper describes the interactive strategies adopted during the composition and realisation of construction 3 for soprano saxophone and multiple media, by Tony Myatt and Peter Fluck. This work is an interactive multiple media composition for computer, computer-enhanced saxophone and computer graphics projected onto irregularly shaped screens. Derivation of the performer sensing system and mapping strategies to control signal processing, computer generated materials and communication gestures between the performer and computer are described. These processes include generative mapping techniques using neural networks for the recognition of gestural information and the development and application of wireless, wearable sensing technology. This work is described as a holistic approach to the derivation of performer sensing, data mapping and the application of reactive and interactive processes in the context of the creation of a new musical and multiple media composition.

The following article offers an analytical overview of the currently available software technologies designed to assist in creation, dissemination, and most importantly performance of interactive electroacoustic art. By grouping the software into two basic groups based on their interfaces, my aim is to provide a comprehensive list of two groups' strengths and shortcomings, therefore exposing common issues that arise whenever a composer utilises such software interfaces in performance settings. Finally, as an incentive in solving a number of given problems, the author will present RTMix, his own software creation that has been designed primarily as a standardised interface for the purpose of easier production, performance and dissemination of the interactive electroacoustic artwork.