The Ghost in the Keys: A Disklavier Demo for Human-AI Musical Co-Creativity

While generative models for music composition are increasingly capable, their adoption by musicians is often hindered by the iterative paradigm of text-prompting. This workflow is disconnected from the embodied, responsive nature of instrumental performance. To address this, we introduce Aria-Duet, an interactive system facilitating a real-time musical duet between a human pianist and Aria, a generative model, using a Yamaha Disklavier as a shared physical interface. The framework enables a turn-taking collaboration: the user performs, signals a handover, and the model generates a coherent continuation performed acoustically on the piano. After first describing the technical architecture enabling this low-latency interaction on consumer hardware, we analyze the resulting system through sessions with pianists, giving insights into the real-time auto-complete paradigm it presents. Overall, we find that this interactive framework works naturally with trained pianists, and that further post-training to the model could further improve the co-creative experience.