In Part II of an extended profile of the new-music powerhouse (see Part I here), Allan Kozinn gives an overview of the now-renowned composers and ensembles that Bang on a Can spawned and/or nurtured – not to mention a record label, a summer festival (popularly referred to as “Banglewood”), an educational program, and an avant-garde marching band – and considers the changes that the Bangers wrought in the entire U.S. musical ecosystem.