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author Atamanenko, Oleg
Chalova, Anna
Coombes, Joseph
Cope, Nikki
Dang, Phillip
Deng, Zhifeng
Du, Jimmy
Ermolenko, Michael
Fan, Feifan
Feng, Yufei
Fichter, Cheryl
Filimonov, Pavel
Fischer, Louis
Gibbs, Kylan
Gusarova, Valeria
Karpik, Pavel
Kottner, Andreas Assad
Lee, Ian
Louie, Oliver
Mai, Jasmine
Mamontov, Mikhail
Mao, Suri
Morshed, Nurullah
Poletaev, Igor
Radu, Florin
Semernia, Dmytro
Shingarev, Evgenii
Sivaraja, Vikram
Skirko, Peter
Takhautdinov, Rinat
Villahermosa, Robert
Wang, Jean
author_facet Atamanenko, Oleg
Chalova, Anna
Coombes, Joseph
Cope, Nikki
Dang, Phillip
Deng, Zhifeng
Du, Jimmy
Ermolenko, Michael
Fan, Feifan
Feng, Yufei
Fichter, Cheryl
Filimonov, Pavel
Fischer, Louis
Gibbs, Kylan
Gusarova, Valeria
Karpik, Pavel
Kottner, Andreas Assad
Lee, Ian
Louie, Oliver
Mai, Jasmine
Mamontov, Mikhail
Mao, Suri
Morshed, Nurullah
Poletaev, Igor
Radu, Florin
Semernia, Dmytro
Shingarev, Evgenii
Sivaraja, Vikram
Skirko, Peter
Takhautdinov, Rinat
Villahermosa, Robert
Wang, Jean
contents We introduce Inworld TTS-1, a set of two Transformer-based autoregressive text-to-speech (TTS) models. Our largest model, TTS-1-Max, has 8.8B parameters and is designed for utmost quality and expressiveness in demanding applications. TTS-1 is our most efficient model, with 1.6B parameters, built for real-time speech synthesis and on-device use cases. By scaling train-time compute and applying a sequential process of pre-training, fine-tuning, and RL-alignment of the speech-language model (SpeechLM) component, both models achieve state-of-the-art performance on a variety of benchmarks, demonstrating exceptional quality relying purely on in-context learning of the speaker's voice. Inworld TTS-1 and TTS-1-Max can generate high-resolution 48 kHz speech with low latency, and support 11 languages with fine-grained emotional control and non-verbal vocalizations through audio markups. We additionally open-source our training and modeling code under an MIT license.
format Preprint
id arxiv_https___arxiv_org_abs_2507_21138
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle TTS-1 Technical Report
Atamanenko, Oleg
Chalova, Anna
Coombes, Joseph
Cope, Nikki
Dang, Phillip
Deng, Zhifeng
Du, Jimmy
Ermolenko, Michael
Fan, Feifan
Feng, Yufei
Fichter, Cheryl
Filimonov, Pavel
Fischer, Louis
Gibbs, Kylan
Gusarova, Valeria
Karpik, Pavel
Kottner, Andreas Assad
Lee, Ian
Louie, Oliver
Mai, Jasmine
Mamontov, Mikhail
Mao, Suri
Morshed, Nurullah
Poletaev, Igor
Radu, Florin
Semernia, Dmytro
Shingarev, Evgenii
Sivaraja, Vikram
Skirko, Peter
Takhautdinov, Rinat
Villahermosa, Robert
Wang, Jean
Computation and Language
Artificial Intelligence
Machine Learning
Sound
Audio and Speech Processing
We introduce Inworld TTS-1, a set of two Transformer-based autoregressive text-to-speech (TTS) models. Our largest model, TTS-1-Max, has 8.8B parameters and is designed for utmost quality and expressiveness in demanding applications. TTS-1 is our most efficient model, with 1.6B parameters, built for real-time speech synthesis and on-device use cases. By scaling train-time compute and applying a sequential process of pre-training, fine-tuning, and RL-alignment of the speech-language model (SpeechLM) component, both models achieve state-of-the-art performance on a variety of benchmarks, demonstrating exceptional quality relying purely on in-context learning of the speaker's voice. Inworld TTS-1 and TTS-1-Max can generate high-resolution 48 kHz speech with low latency, and support 11 languages with fine-grained emotional control and non-verbal vocalizations through audio markups. We additionally open-source our training and modeling code under an MIT license.
title TTS-1 Technical Report
topic Computation and Language
Artificial Intelligence
Machine Learning
Sound
Audio and Speech Processing
url https://arxiv.org/abs/2507.21138