In recent years we have seen a proliferation of musical tables. Believing that this is not just the result of a tabletop trend, in this paper we first discuss several of the reasons for which live music performance and HCI in general, and musical instruments and tabletop interfaces in particular, can lead to a fertile two-way cross-pollination that can equally benefit both fields. After that, we present the reacTable, a musical instrument based on a tabletop interface that exemplifies several of these potential achievements. Author Keywords Tangible interfaces, tabletop interfaces, musical instrument, musical performance, design, interaction techniques. ACM Classification Keywords H.5.2 [User Interfaces]: interaction styles, input devices and strategies J.5: [Arts and Humanities]: performing arts.

This paper first introduces two previous software-based music instruments designed by the author, and analyses the crucial importance of the visual feedback introduced by their interfaces. A quick taxonomy and analysis of the visual components in current trends of interactive music software is then proposed, before introducing the reacTable*, a new project that is currently under development. The reacTable* is a collaborative music instrument, aimed both at novices and advanced musicians, which employs computer vision and tangible interfaces technologies, and pushes further the visual feedback interface ideas and techniques aforementioned.

This paper begins with some of the topics and questions about music improvisation using computers, the author has posed himself during more than a decade experience as a performer, composer, software designer and educator. After a quick review of several of his previous interactive music systems, some of those issues are then confronted in FMOL, a program initially designed as a tool for on-line collaborative composition that has been used by hundreds of on-line composers, and which is also being employed by the author in free-form audiovisual improvisation concerts . 1

multidisciplinary area that tightly relates technology and artistic creation. In this paper, the author first exposes some of the questions he has posed himself during more than a decade experience as a performer, composer, interface and software designer, and educator. Finally, he illustrates these topics with some examples of his work.

In this paper we study the potential and the challenges posed by multi-user instruments, as tools that can facilitate interaction and responsiveness not only between performers and their instrument but also between performers as well. Several previous studies and taxonomies are mentioned, after what different paradigms exposed with examples based on traditional mechanical acoustic instruments. In the final part, several existing systems and implementations, now in the digital domain, are described and identified according to the models and paradigms previously introduced.

In this paper the authors propose a new architecture and new features for collaborative music composition. These design principles have been applied, without any loss of generality, to a system that has already been extensively tested on-line for the last three years, and which has allowed composers from around the world to participate in the collective creation of two important theatrical scores. They can constitute the basis for new approaches for collective composition on the Internet.

In recent years we have seen a proliferation of musical tables. Believing that this is not just the result of a tabletop trend, in this paper I first discuss the reasons that make tabletop interfaces promising musical interfaces. After that, I present the reactable, a musical instrument based on a tabletop interface that exemplifies several of these potential achievements. Author Keywords Reactable, tangible interfaces, tabletop interfaces, musical instrument, musical performance, design, interaction techniques. ACM Classification Keywords H.5.2 [User Interfaces]: interaction styles, input devices and strategies J.5: [Arts and Humanities]: performing arts.