Tapping into the Internet as an Acoustical Medium

Chris Chafe, Ph.D.

Center for Computer Research in Music and Acoustics

Stanford University

Date: Friday, May 18, 2007
Place: Buchanan 1930
Time: 2:00 pm — 3:00 pm


Abstract:

Recent work in network audio transport transforms advanced networks into a new kind of acoustical medium in which sound waves propagate as if traveling through air, water, or solids. Waves sent through the medium are reflected or altered as they bounce between hosts. Propagation delays are used to create echo chambers and build the resonances for "distributed musical instruments." As a side-effect, tones created by network resonances can be used to monitor the quality of the underlying network.

The presentation presents three areas of research:

1) auditory methods for monitoring QoS, especially for networks supporting real-time, interactive, bidirectional flows

2) remote musical collaboration using professional-quality, low-latency audio

3) empirical study of human factors affected by some unique acoustical properties of the medium

Network latency, jitter and delay asymmetry affect the speed of sound and are never uniform. By creating distributed virtual sound objects like instruments and rooms and by studying distributed ensembles, we can begin to understand this new sound world. Some effects have been measured empirically and the results contain some surprises. For example, latencies can be low enough that musicians at opposite ends of a path are essentially in the same room, and echo cancellation becomes unnecessary. Multi-channel "echo construction" can be designed to enrich the experience. For audio use, the new territory that is opening is unlike any previous telecommunications medium.

CHRISTOPHER CHAFE is a composer/ cellist / music researcher with an interest in computer music composition and interactive performance. He has been a long-term denizen of the Center for Computer Research in Music and Acoustics, Stanford University where he directs the center and teaches computer music courses. His doctorate in music composition was completed at Stanford in 1983 with prior degrees in music from the University of California at San Diego and Antioch College. Two year-long research periods were spent at IRCAM, and the Banff Center for the Arts developing methods for computer sound synthesis based on physical models of musical instrument mechanics. A current project, "SoundWIRE", explores musical collaboration and network evaluation using high-speed internets for high-quality sound. He has performed his music in Europe, the Americas and Asia, and composed soundtracks for documentary films. Two recent discs of his works are available from Centaur Records. In Spring 2001, a collaboration with artist Greg Niemeyer entitled "Ping" was exhibited at FMOMA and online via the Walker Art Center, and in Sept. 2004 at Parc de la Villette, Paris. A second collaboration, "Oxygen Flute," was created for the San Jose Museum of Art. A CD of
music from both installations is available, entitled "Extrasensory Perceptions."

Host: Prof. Curtis Roads, Media Arts and Technology