Adventurous New York vocal group Choral Chameleon return to Middlebury College’s Mahaney Arts Center for the first time since their highly regarded sold-out shows in 2022. The boundary-breaking singers bring two unique new performances to Vermont audiences: The first, a program titled “Control,” features the group’s distinct, rich harmonies and delves into the complexity of parent-child relationships. The second, four days later, is less concert and more vocal installation, with singers (including voices from the college’s community) stationed all around the building for attendees to discover at their own pace — a kind of musical “choose your own adventure.”