JAM: A Tiny Flow-based Song Generator with Fine-grained Controllability and Aesthetic Alignment

Liu Renhang, Chia-Yu Hung, Navonil Majumder, Dorien Herremans, Soujanya Poria


Abstract
Diffusion and flow-matching models have revolutionized automatic text-to-audio generation, increasingly capable of generating high-quality audio outputs for speech and acoustic events. However, creative audio generation involving music and songs still has room for improvement. Recent open lyrics-to-song models like DiffRhythm, ACE-Step, and LeVo have set an acceptable standard for recreational use but lack the fine-grained word-level controllability desired by musicians. To our knowledge, our flow-matching-based JAM is the first to provide word-level timing and duration control in song generation, enabling fine-grained vocal control. To better align generated songs with human preferences, we implement aesthetic alignment through Direct Preference Optimization, iteratively refining the model using a synthetic dataset without manual annotations. Additionally, we aim to standardize evaluation of lyrics-to-song models through our public evaluation dataset JAME. We demonstrate that JAM outperforms open models on music-specific attributes.
Anthology ID:
2026.findings-emnlp.48
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
966–981
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.48/
DOI:
Bibkey:
Cite (ACL):
Liu Renhang, Chia-Yu Hung, Navonil Majumder, Dorien Herremans, and Soujanya Poria. 2026. JAM: A Tiny Flow-based Song Generator with Fine-grained Controllability and Aesthetic Alignment. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 966–981, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
JAM: A Tiny Flow-based Song Generator with Fine-grained Controllability and Aesthetic Alignment (Renhang et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.48.pdf