M3-TTS: Native Two-Stream Multi-Modal Diffusion Transformer for Zero-Shot Speech Synthesis

Xiaopeng Wang, Chunyu Qiang, Ruibo Fu, Zhengqi Wen, Yuxin Guo, Xuefei Liu, Yukun Liu, Yuzhe Liang, Kang Yin, Teng Ma, Yushen Chen, Yuankun Xie, Chenxing Li, Changsheng Li


Abstract
Zero-shot text-to-speech (TTS) aims to synthesize high-quality speech for unseen speakers using only a short reference utterance. Existing non-autoregressive TTS models typically convert text tokens into speech-length representations through filler-token padding, explicit duration prediction, or text upsampling. However, these approaches either introduce redundant computation or rely on explicit alignment assumptions. We propose M3-TTS, a native two-stream multi-modal diffusion Transformer that preserves the original lengths of text and speech representations and enables direct text–speech interaction through packed joint self-attention. M3-TTS employs a dual-stage architecture consisting of Joint-DiT layers for learning text–speech correspondence and audio-only DiT layers for acoustic refinement. Reference acoustic information is injected through AdaLN-style conditioning. Experiments on the Seed-TTS benchmark demonstrate strong intelligibility and competitive speaker similarity and perceptual quality. The Mel-VAE variant further improves inference efficiency while maintaining high synthesis quality. Code and demos will be available at https://github.com/WWWWxp/M3-TTS.
Anthology ID:
2026.findings-emnlp.240
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:
5061–5071
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URL:
https://aclanthology.org/2026.findings-emnlp.240/
DOI:
Bibkey:
Cite (ACL):
Xiaopeng Wang, Chunyu Qiang, Ruibo Fu, Zhengqi Wen, Yuxin Guo, Xuefei Liu, Yukun Liu, Yuzhe Liang, Kang Yin, Teng Ma, Yushen Chen, Yuankun Xie, Chenxing Li, and Changsheng Li. 2026. M3-TTS: Native Two-Stream Multi-Modal Diffusion Transformer for Zero-Shot Speech Synthesis. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 5061–5071, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
M3-TTS: Native Two-Stream Multi-Modal Diffusion Transformer for Zero-Shot Speech Synthesis (Wang et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.240.pdf