“Unsilent Night” is caroling for the new millennium — even though the piece was written 20 years ago. An experimental sound installation by composer Phil Kline, “Unsilent Night” consists of four different tracks of music featuring sounds reminiscent of the holidays, like bells and voices singing hymn-like melodies. A group of people with boomboxes or iPods gathers, and each is given one of the four tracks. Then they all press play at the same time and wander the streets, creating what Kline called “a city-block-long stereo system.” It’s been performed all over the world since its debut in 1992 in New York, and Charleston’s New Music Collective has organized performances downtown for the past six years. “People are often confused by what they see and hear in a moving sound installation, and it makes for great people watching,” says the Collective’s Ron Wiltrout. “Most of the time we get smiles, but sometimes we just get confused looks, which I think is great. Experimental art should create a sense of wonder.” And don’t be afraid of the “experimental” part, Wiltrout says. “The music is a challenging listen, but it’s also easy to accept it as beautiful.” We’ve listened, and we agree. To sign up as a participant, RSVP to firstname.lastname@example.org.