"It's a Christmas event that isn't corny or naff," says Daz Chandler, the organiser of Unsilent Night.
"This is for people who want to do something different around the silly season, who aren't into the whole Christian carolling side of things."
Unsilent Night is a composition by New York composer Phil Kline designed to be performed as a street parade by whoever turns up with a boombox.
It was first staged in 1992; last year's New York parade attracted 1500 participants. This Saturday night it will be performed in New York, San Diego and, thanks to Chandler, Sydney.
Chandler was given a recording of the New York parade for her 2SER-FM show last year and decided to organise the inaugural Australian parade in 2005.
"We asked Phil and he was stoked, so we bought a heap of cassette tapes - you can't do it on CDs because they skip - and stayed up all hours duplicating," she says. "It was great fun so we decided we'd definitely to do it again."
The symphony is arranged in four layers and distributed on cassettes to participants, along with a map of the route through the CBD, St James, Hyde Park and Oxford Street.
"It's timed so you get to Taylor Square and you're standing there [for] five minutes and it finishes and everyone goes, 'Wow, that was insane.' It attracts a lot of attention from normal people. They're having dinner and they look up and there's all these people carrying stereos on their heads."
It draws a wide range of participants.
"I was expecting the usual suspects: art students, people into weird stuff, musicians, but there were also families," Chandler says. "We had a women who was in her 80s.
"It feels magical, it also feels a trifle naughty. It's really great to do stuff with people you've never met before and feel like you're all united in something."