Present systems for streaming digital audio between devices connected by internet have been limited by a number of compromises. Because of restricted bandwidth and “best effort ” delivery, signal compression of one form or another is typical. Buffering of audio data which is needed to safeguard against delivery uncertainties can cause signal delays of seconds. Audio is in general an unforgiving test of networking, e.g., one data packet arriving too late and we hear it. Trade-offs of signal quality have been necessary to avoid this basic fact and until now, have vied against serious musical uses. Beginning in late 1998, audio applications specifically designed for next-generation networks were initiated that could meet the stringent requirements of professional-quality music streaming. A related experiment was begun to explore the use of audio as a network measurement tool. SoundWIRE (sound waves over the internet from real-time echoes) creates a sonar-like ping to display to the ear qualities of bidirectional connections. Recent experiments have achieved coast-to-coast sustained audio connections whose round trip times are within a factor of 2 of the speed of light. Full-duplex speech over these connections feels comfortable and in an IIR recirculating form that creates echoes like SoundWIRE, users can experience singing into a transcontinental echo chamber. Three simplifications to audio streaming are suggested in this paper: Compression has been eliminated to reduce delay and enhance signal-quality. TCP/IP is used in unidirectional flows for its delivery guarantees and thereby eliminating the need for application software to correct transmission errors. QoS puts bounds on latency and jitter affecting long-haul bidirectional flows. 1.

The ubiquitous nature of communication in computer networks, firmly manifested in the Internet era, provided a context for the introduction of different collaborative tools widely accepted by the on-line community, such as textual chats, white boards, shared editors, video conference systems, shared spaces for the exchange of multimedia documents or even simple e-mail based collaborative systems.

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.

communication Commercial videoconferencing products have begun to reach a level of quality acceptable for many lowintensity interactions. However, these systems fail to deliver true “high-fidelity ” that serves as a viable alternative to physical co-presence for more demanding interactions. The solution, we believe, lies in the synergy between high bandwidth networks and the application of information technologies that take advantage of such networks. Specifically, computation can be employed to enrich the communication channel, exploiting an awareness of users’ activity in order to better support their needs. In this manner, we are entering an era of communication in which distance need no longer dictate limitations on high quality distributed experiences and interaction. 1

Electronic classrooms offer instructors a variety of multimedia presentation tools such as the VCR, document camera, and computer projection, allowing for the display of video clips, transparencies, and computer generated simulations and animations. Unfortunately, even the most elegant user interfaces still frustrate many would-be users. The technology tends to be underutilized because of the cognitive effort and time its use requires. Worse still, it often distracts the instructor from the primary pedagogical task.

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The design of a platform for bi-directional musical performance using modern WAN networks poses several challenges that are different from related applications, e.g., synchronous LAN studio systems or uni-directional WAN streaming. The need to minimize as much as possible audio latency and also maximize audio quality requires specific strategies which are informed, in part, by musical decisions. We present some of the key design elements of the Jack-Trip application which has evolved through several years of deployment in musical work over wide-area networks. 1.

On September 23, 2000, a jazz group performed in a concert hall at McGill University in Montreal and the recording engineers mixing the 12 channels of uncompressed PCM audio during the performance were not in a booth at the back of the hall, but rather in a theatre at the University of Southern California in Los Angeles. To our knowledge, this is the first time that live audio of this quality has been streamed over the Internet.

Low-latency, high-quality audio transmission over next-generation Internet is a reality. Bidirectional, multichannel flows over continental distances have been demonstrated in musical jam sessions and other experimental situations. The dominating factors affecting delay are no longer system issues, but the transmission time bounded by lightspeed. This paper addresses a method for creating shared acoustical spaces by “echo construction. ” Where delays in bidirectional paths are sufficiently short and “room-sized, ” they can be used to advantage as components in synthetic, composite reverberation.