STAGE: Stemmed Accompaniment Generation through Prefix-Based Conditioning

Abstract

Recent advances in generative models have made it possible to create high-quality, coherent music, with some systems delivering production-level output. Yet, most existing models focus solely on generating music from scratch, limiting their usefulness for musicians who want to integrate such models into a human, iterative composition workflow. In this paper we introduce STAGE, our STemmed Accompaniment GEneration model, fine-tuned from the state-of-the-art MusicGen to generate single-stem instrumental accompaniments conditioned on a given mixture. Inspired by instruction-tuning methods for language models, we extend the transformer’s embedding matrix with a context token, enabling the model to attend to a musical context through prefix-based conditioning. Compared to the baselines, STAGE yields accompaniments that exhibit stronger coherence with the input mixture, higher audio quality, and closer alignment with textual prompts. Moreover, by conditioning on a metronome-like track, our framework naturally supports tempo-constrained generation, achieving state-of-the-art alignment with the target rhythmic structure–all without requiring any additional tempo-specific module. As a result, STAGE offers a practical, versatile tool for interactive music creation that can be readily adopted by musicians in real-world workflows.

Publication
International Society for Music Information Retrieval Conference
Giorgio Strano
Giorgio Strano
PhD Student
Donato Crisostomi
Donato Crisostomi
PostDoctoral Researcher

My research interests revolve around artificial intelligence, in particular mechanistic interpretability, model merging and representational alignment.

Michele Mancusi
Michele Mancusi
PostDoctoral Researcher

PhD Student @SapienzaRoma CS | Intern @Musixmatch | Intern @Microsoft | Research Scientist @Sony | Senior Research Scientist @Moises

Luca Cosmo
Luca Cosmo
Associate Professor, Ca’ Foscari University of Venice
Emanuele Rodolà
Emanuele Rodolà
Full Professor