Can music emerge from a swarm of robots each playing a single note and coordinating its behaviour with the others? We explore this idea by proposing a modular framework for the emergent generation of music, representing a novel intersection between robotics and artistic creation. We move beyond the works that link sound to robot movements or that allocate robots to musical roles. In our system, despite being limited to playing the atomic musical element, i.e., a single note, robots self-organise to play musical creations collectively. We illustrate the modular architecture of our framework by presenting three independent modules that run in parallel to enable the swarm to reach (i) temporal coordination so that robots play in synchrony, (ii) harmonic consensus so that notes are harmonically coherent, and (iii) beat distribution so that notes are distributed throughout time. We implement algorithms for the three modules building upon and extending existing swarm robotics solutions. Our bottom-up and modular approach also enables the use of cheap and accessible robots, hence fostering applicability, scalability, and robustness. Finally, combining the robot’s physical embodiment with the swarm’s plurality brings a unique dimension to the musical performance. We showcase our collaborative music creation framework with simulations and a real robot performance comprising 12 robots. This study shows the potential of combining music with swarm robotics to create musical complexity from simple robotic actions.