This paper takes an empirical and processual approach to the study of coordinated group activity through enacted and experimental movement research with responsive media. We focus on the dynamic emergence of what we will refer to as ensemble. Informed by readings from process philosophy and new materialism, we take into account the vitality of matter in investigating a notion of subjectivity unhinged from compartmentalized conceptions of the human. Methodologically we suspend ontological assumptions which occlude, mask, or ignore emergent relations and unprestatable events. These concerns underline the design tactics of an immersive media environment and apparatus for research creation. The Lanterns digital-physical system employs a design ethos of semantically shallow computation towards an experientially responsive environment. We give an overview of the motivating questions for this line of enacted inquiry and describe our experimental process and outcomes with the Lanterns.