Monday, July 30, 2007

Choir hopes for a good time on the web

Anyone who sings in a large choir will be familiar with the problem of acoustic lag - the 1/50th of a second it takes sound to travel from one end of a large stage to another. Although barely perceptible, this lag can interfere with the singers' timing, and it is the bane of choir directors everywhere.

But Barry Cheetham has a far bigger problem. He wants to direct an "internet choir", with singers separated by a up to a thousand miles performing simultaneously. It'll be more challenging than even the roomiest stage, but that doesn't deter Cheetham.

"It is a passion. I can't pretend otherwise. I do love singing. But I'm primarily a computer scientist," says Cheetham, a senior lecturer at the University of Manchester, and a bass in the university chorus.

The big issue is latency - the lag from the time a signal is sent to the time an answer is received. For a telephone conversation, latency of up to 300 milliseconds is considered acceptable. For musicians trying to perform together, even 50 ms is a problem. Unfortunately, 50 ms is also a pretty typical latency on a commercial broadband connection.

So Cheetham is trying to get funding to build an experimental network than can reduce the lag to acceptable levels. If he succeeds, the same research could mean better internet telephony and improved remote robotics.

Ultimately, he dreams of amateur choruses from around Europe teaming up to sing Bach or Handel together - with everyone starting and ending at the same time.

Kurt Kleiner, New Scientist contributor

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