What are Open Source Voice Cloning Models?
Open source voice cloning models are specialized AI systems that create synthetic speech from text input while mimicking specific voice characteristics. Using deep learning architectures like autoregressive transformers and neural vocoders, they can generate natural-sounding speech that replicates target voices with remarkable accuracy. This technology allows developers and creators to build voice synthesis applications, dubbing tools, and personalized speech systems with unprecedented freedom. They foster collaboration, accelerate innovation, and democratize access to powerful voice cloning tools, enabling a wide range of applications from content creation to enterprise voice solutions.
Fish Speech V1.5
Fish Speech V1.5 is a leading open-source text-to-speech (TTS) model that employs an innovative DualAR architecture with dual autoregressive transformer design. It supports multiple languages with over 300,000 hours of training data for English and Chinese, and over 100,000 hours for Japanese. With an exceptional ELO score of 1339 in TTS Arena evaluations, it achieves remarkable accuracy with 3.5% WER for English and 1.2-1.3% CER for both English and Chinese.
Fish Speech V1.5: Leading Multilingual Voice Synthesis
Fish Speech V1.5 is a leading open-source text-to-speech (TTS) model that employs an innovative DualAR architecture with dual autoregressive transformer design. It supports multiple languages with over 300,000 hours of training data for English and Chinese, and over 100,000 hours for Japanese. In independent evaluations by TTS Arena, the model performed exceptionally well, with an ELO score of 1339. The model achieved a word error rate (WER) of 3.5% and a character error rate (CER) of 1.2% for English, and a CER of 1.3% for Chinese characters, making it ideal for professional voice cloning applications.
Pros
- Innovative DualAR architecture with dual autoregressive transformers.
- Massive training dataset with 300k+ hours for major languages.
- Top-tier ELO score of 1339 in TTS Arena evaluations.
Cons
- Higher pricing at $15/M UTF-8 bytes on SiliconFlow.
- May require significant computational resources for optimal performance.
Why We Love It
- It delivers industry-leading multilingual voice synthesis with proven performance metrics, making it perfect for professional voice cloning applications.
CosyVoice2-0.5B
CosyVoice 2 is a streaming speech synthesis model based on a large language model with unified streaming/non-streaming framework design. It achieves ultra-low latency of 150ms in streaming mode while maintaining exceptional quality. Compared to version 1.0, it reduces pronunciation errors by 30-50% and improves MOS score from 5.4 to 5.53, with fine-grained control over emotions and dialects.
CosyVoice2-0.5B: Ultra-Low Latency Streaming Voice Synthesis
CosyVoice 2 is a streaming speech synthesis model based on a large language model, employing a unified streaming/non-streaming framework design. The model enhances speech token codebook utilization through finite scalar quantization (FSQ) and develops a chunk-aware causal streaming model. In streaming mode, it achieves ultra-low latency of 150ms while maintaining synthesis quality nearly identical to non-streaming mode. Compared to version 1.0, pronunciation error rates have been reduced by 30-50%, MOS score improved from 5.4 to 5.53, and it supports fine-grained control over emotions and dialects across Chinese (including Cantonese, Sichuan, Shanghainese, Tianjin), English, Japanese, and Korean.
Pros
- Ultra-low latency of 150ms in streaming mode.
- 30-50% reduction in pronunciation errors vs. v1.0.
- Improved MOS score from 5.4 to 5.53.
Cons
- Smaller model size may limit some advanced capabilities.
- Streaming quality, while excellent, may not match non-streaming in all cases.
Why We Love It
- It offers the perfect balance of speed and quality for real-time voice cloning applications with exceptional emotional and dialect control.
IndexTTS-2
IndexTTS2 is a breakthrough auto-regressive zero-shot Text-to-Speech model designed for precise duration control, crucial for applications like video dubbing. It achieves disentanglement between emotional expression and speaker identity, enabling independent control over timbre and emotion. The model incorporates GPT latent representations and features soft instruction mechanisms based on text descriptions for enhanced emotional control.
IndexTTS-2: Zero-Shot Voice Cloning with Precise Control
IndexTTS2 is a breakthrough auto-regressive zero-shot Text-to-Speech (TTS) model designed to address precise duration control challenges in large-scale TTS systems. It introduces a novel method for speech duration control with two modes: explicit token specification for precise duration and free auto-regressive generation. The model achieves disentanglement between emotional expression and speaker identity, enabling independent control over timbre and emotion via separate prompts. It incorporates GPT latent representations and utilizes a three-stage training paradigm to enhance speech clarity in emotional expressions. A soft instruction mechanism based on text descriptions, developed by fine-tuning Qwen3, effectively guides emotional tone generation. Experimental results show IndexTTS2 outperforms state-of-the-art zero-shot TTS models in word error rate, speaker similarity, and emotional fidelity.
Pros
- Breakthrough zero-shot voice cloning capabilities.
- Precise duration control for video dubbing applications.
- Independent control over timbre and emotional expression.
Cons
- Complex architecture may require advanced technical expertise.
- Both input and output pricing at $7.15/M UTF-8 bytes on SiliconFlow.
Why We Love It
- It revolutionizes voice cloning with zero-shot capabilities and unprecedented control over duration, emotion, and speaker characteristics for professional applications.
Voice Cloning Model Comparison
In this table, we compare 2025's leading open source voice cloning models, each with unique strengths. Fish Speech V1.5 offers industry-leading multilingual performance, CosyVoice2-0.5B excels in real-time streaming with emotional control, while IndexTTS-2 provides breakthrough zero-shot capabilities with precise duration control. This side-by-side view helps you choose the right tool for your specific voice cloning needs.
| Number | Model | Developer | Subtype | Pricing (SiliconFlow) | Core Strength |
|---|---|---|---|---|---|
| 1 | Fish Speech V1.5 | fishaudio | Text-to-Speech | $15/M UTF-8 bytes | Multilingual excellence with DualAR |
| 2 | CosyVoice2-0.5B | FunAudioLLM | Text-to-Speech | $7.15/M UTF-8 bytes | Ultra-low latency streaming |
| 3 | IndexTTS-2 | IndexTeam | Text-to-Speech | $7.15/M UTF-8 bytes | Zero-shot with duration control |
Frequently Asked Questions
Our top three picks for 2025 are Fish Speech V1.5, CosyVoice2-0.5B, and IndexTTS-2. Each of these models stood out for their innovation, performance, and unique approach to solving challenges in voice cloning, text-to-speech synthesis, and real-time voice generation.
Our analysis shows different leaders for specific needs: Fish Speech V1.5 is ideal for high-quality multilingual voice cloning with proven accuracy metrics. CosyVoice2-0.5B excels in real-time applications requiring ultra-low latency and emotional control. IndexTTS-2 is perfect for professional applications like video dubbing that need precise duration control and zero-shot voice cloning capabilities.