Diagnose, Then Refine: A Closed-Loop TTS System with AudioLLM-guided Correction

Zeyang Song, Tianchi Liu, Tianrui Wang, Chenglin Xu, Steven Y. Guo, Haizhou Li


Abstract
Current TTS systems typically rely on open-loop, single-pass generation and can produce sporadic local prosodic defects, such as misplaced stress, unnatural pauses, or flattened intonation, that utterance-level metrics often fail to expose. We present LoopTTS, a judge-guided Filter-Judge-Refiner framework for recovering low-quality TTS outputs diagnosed by an AudioLLM. Given an initial utterance from a base TTS model, an AudioLLM Judge identifies salient prosodic issues and generates structured refine instructions; a Refiner, our fine-grained instruction-following TTS model, then performs guided expressive re-synthesis conditioned on the initial utterance, target text, and instruction. To train the Refiner, we construct Refiner-DB, a 42K-example AudioLLM-annotated dataset with word-level prosodic weak supervision. Human evaluation on diagnosed low-quality utterances shows that LoopTTS can detect perceptually salient errors and correct them with the Refiner, outperforming raw generated audio and practical open-loop re-generation baselines in recovery quality. The Refiner also demonstrates stronger instruction-following ability for stress and pause control in targeted prosody modification. LoopTTS is available at https://github.com/Pooookeman/LoopTTS.
Anthology ID:
2026.emnlp-main.1229
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
28041–28059
Language:
URL:
https://aclanthology.org/2026.emnlp-main.1229/
DOI:
Bibkey:
Cite (ACL):
Zeyang Song, Tianchi Liu, Tianrui Wang, Chenglin Xu, Steven Y. Guo, and Haizhou Li. 2026. Diagnose, Then Refine: A Closed-Loop TTS System with AudioLLM-guided Correction. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 28041–28059, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Diagnose, Then Refine: A Closed-Loop TTS System with AudioLLM-guided Correction (Song et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.1229.pdf