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 recent years Computer Network-Music has increasingly captured the attention of the Computer Music Community. With the advent of Internet communication, geographical displacement amongst the participants of a computer mediated music performance achieved world wide extension. However, when established over long distance networks, this form of musical communication has a fundamental problem: network latency (or net-delay) is an impediment for real-time collaboration. From a recent study, carried out by the authors, a relation between network latency tolerance and Music Tempo was established. This result emerged from an experiment, in which simulated network latency conditions were applied to the performance of different musicians playing jazz standard tunes.