As audio and music applications tend to a higher level of abstraction and to fill in the gap between the signal processing world and the end-user we are more and more interested on processing content and not (only) signal. This change in point of view leads to the redefinition of several “classical” concepts, and a new conceptual framework needs to be set to give support to these new trends. In [2], a model for the transmission of audio content was introduced. The model is now extended to include the idea of Sound Objects. With these thoughts in mind, examples of design decisions that have led to the implementation of the CLAM framework are also given.

In this paper we describe "The Public Sound Objects" project and its context. This project, which is currently under development, approaches Internet collaborative music performance, going beyond most common paradigms where the network is mainly used as a channel to provide a connection between performative spaces. The system will provide an on-line public performance space where people can be found participating in an ongoing collaborative sonic event. The users connected to this installation control a server side synthesis engine through a web-based interface. The resulting "Sound Objects" form a sonic piece that is then streamed back to each user. The user takes the role of a performer and his contribution has a direct and unique influence on the overall resulting soundscape. This ongoing event is also played back at the installation for a live audience, with added contextual elements such as sound spacialization and metaphorical visual representations of current participants.

In an interactive system designed to produce music, the sound synthesis engine and the user interface layer are fully integrated, but usually designed in parallel and in a modular way. Decoupling the interface layer from the synthesis engine, not only allows the use of best suited technologies and programming languages for each purpose, but also enhances the overall system flexibility. This paper discusses the idea behind a remote user interface and a processing engine that resides in a different host, taken to the most extreme situation in which a user can access the synthesizer from any place in the world using internet technology. This paradigm has promising applications in collaborative music creation systems for geographically displaced communities of user. The Public Sound Objects is an experimental system on which this concept is applied, and its currently under development at the Music Technology Group of the UPF in Barcelona.