Open-Source TTS Model Selection Guide

Introduction

With the rapid advancement of AI speech synthesis technology, the open-source TTS community has produced a number of excellent models and tools that are narrowing the gap with commercial services—and in some specific scenarios even demonstrating unique advantages. This article provides a side-by-side comparison of the most prominent open-source TTS projects to help developers make informed choices based on their specific needs.

ChatTTS: Conversational Speech Synthesis

ChatTTS was one of the hottest TTS open-source projects on GitHub in 2024, focused on conversational speech synthesis. Its biggest strength lies in its ability to generate speech with natural prosody and colloquial expression that feels very close to real human conversation. ChatTTS performs exceptionally well in Chinese and supports paralinguistic features like laughter and pauses, making it ideal for chatbots, virtual streamers, and other conversational scenarios. The project has an active community and is relatively easy to deploy, though it does require decent hardware.

Key Point: ChatTTS excels in Chinese with natural prosody, supports laughter and pauses, ideal for chatbots and virtual streamers.

Fish Speech: Zero-Shot Voice Cloning

Fish Speech is another noteworthy Chinese TTS open-source project, specializing in zero-shot voice cloning and efficient inference speed. Fish Speech supports multiple languages including Chinese, Japanese, English, and Korean, and can clone a target voice using just a few seconds of reference audio, delivering excellent voice similarity and naturalness. The project’s inference code is optimized to achieve fast synthesis speeds even on consumer-grade GPUs, making it a strong choice for developers needing voice cloning capabilities.

Key Point: Fish Speech supports multilingual zero-shot cloning with fast inference on consumer-grade GPUs.

CosyVoice: Chinese Prosody and Emotion Control

CosyVoice was developed by Alibaba’s Tongyi Lab and employs a streaming autoregressive Transformer architecture, achieving industry-leading performance in Chinese speech synthesis. Its highlights include fine-grained emotion control, zero-shot voice cloning, and prosodic optimization specifically tuned for Chinese. CosyVoice provides complete training and inference code, but the model is large and demands significant GPU memory, making it better suited for teams with solid technical foundations and the willingness to invest in tuning.

Key Point: CosyVoice offers fine-grained emotion control with industry-leading Chinese prosody, but requires significant GPU memory.

GPT-SoVITS: Few-Shot Voice Cloning and Cross-Lingual Transfer

GPT-SoVITS is an innovative project that combines GPT and SoVITS, excelling particularly in few-shot voice cloning and cross-lingual voice transfer. The project offers a user-friendly WebUI interface that lowers the barrier to entry, allowing even non-technical users to quickly experience voice cloning. GPT-SoVITS performs exceptionally well in Chinese and Japanese, and is considered one of the best open-source projects for voice cloning results.

Key Point: GPT-SoVITS provides a user-friendly WebUI for few-shot and cross-lingual voice cloning with exceptional results in Chinese and Japanese.

Summary

In summary: if you prioritize conversational naturalness, ChatTTS is the top choice; if you need voice cloning, Fish Speech or GPT-SoVITS are recommended; and if Chinese prosody and emotional expression are critical, CosyVoice is worth a deep look.