Making noise for silent films

Not many bands would tour as accompaniment to classic silent films. But then, the Alloy Orchestra isn't your normal band. The three-man orchestra scored "Metropolis" in 1991 and has since written for dozens of movies. Tonight, outside at Brandeis's Chapels Field, the musicians will use a mix of found instruments, keyboards, and clarinet to create an aural backdrop for "Chang: A Drama of the Wilderness," a 1927 silent film about a struggling farmer in Thailand. It will be shown on an inflatable screen. 8 p.m. Free. Chapels Field at Brandeis University, 415 South St., Waltham.