Called “James Tenney and Milton Babbitt : American Iconoclasts,” the mini-festival begins on Saturday with a work by Mr. Tenney, who died in 2006, on a program including pieces by Larry Polansky, Michael Byron and Henry Cowell (the 1925 “Ensemble” for string quartet and thundersticks). Mr. Babbitt is honored on Sunday with a program that includes, among other works, a premiere by Christopher Buchenholz.