DT1 is an interactive installation that employs flocking algorithms to produce music and visuals. The user's motions are captured by a video camera and influence the flocks behaviour. Each agent moving in a virtual 3D space controls a MIDI instrument whose playing style depends on the agent's state. In this system, the user acts as a conductor influencing the flock's musical activity. In addition to gestural interaction, the acoustic properties of the system can be modified on the fly by using an intuitive GUI.