What are Open Source Singing Voice Synthesis Models?
Open source singing voice synthesis models are specialized AI systems that convert text into natural-sounding speech and singing voices. Using advanced deep learning architectures like autoregressive transformers and neural vocoders, they generate high-quality vocal output from text descriptions. This technology allows developers and creators to build voice applications, create multilingual content, and develop singing voice synthesis systems with unprecedented freedom. They foster collaboration, accelerate innovation, and democratize access to powerful voice generation tools, enabling a wide range of applications from virtual assistants to musical production and enterprise voice solutions.
Fish Speech V1.5
Fish Speech V1.5 is a leading open-source text-to-speech (TTS) model employing 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 TTS Arena evaluations, it achieved an exceptional ELO score of 1339, with impressive accuracy rates: 3.5% WER and 1.2% CER for English, and 1.3% CER for Chinese characters.
Fish Speech V1.5: Premium Multilingual Voice Synthesis
Fish Speech V1.5 is a leading open-source text-to-speech (TTS) model employing 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.
Pros
- Innovative DualAR architecture with dual autoregressive transformers.
- Massive training dataset with 300,000+ hours for major languages.
- Top-tier TTS Arena performance with 1339 ELO score.
Cons
- Higher pricing compared to other TTS models.
- May require technical expertise for optimal implementation.
Why We Love It
- It delivers industry-leading multilingual voice synthesis with proven performance metrics and innovative dual transformer architecture for professional applications.
CosyVoice2-0.5B
CosyVoice 2 is a streaming speech synthesis model based on large language model architecture, featuring unified streaming/non-streaming framework design. It achieves ultra-low latency of 150ms in streaming mode while maintaining high synthesis quality. Compared to v1.0, it reduces pronunciation errors by 30%-50% and improves MOS score from 5.4 to 5.53, supporting Chinese dialects, English, Japanese, Korean with cross-lingual capabilities.
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 the utilization of the speech token codebook through finite scalar quantization (FSQ), simplifies the text-to-speech language model architecture, and develops a chunk-aware causal streaming matching model that supports different synthesis scenarios. In streaming mode, the model achieves ultra-low latency of 150ms while maintaining synthesis quality almost identical to that of non-streaming mode. Compared to version 1.0, the pronunciation error rate has been reduced by 30%-50%, the MOS score has improved from 5.4 to 5.53, and fine-grained control over emotions and dialects is supported.
Pros
- Ultra-low streaming latency of just 150ms.
- 30%-50% reduction in pronunciation errors vs v1.0.
- Improved MOS score from 5.4 to 5.53.
Cons
- Smaller parameter count (0.5B) compared to larger models.
- Limited to text-to-speech without advanced emotion control.
Why We Love It
- It combines real-time streaming capability with high-quality synthesis, making it perfect for live applications and interactive voice systems.
IndexTTS-2
IndexTTS2 is a breakthrough auto-regressive zero-shot Text-to-Speech model addressing precise duration control challenges. It features disentanglement between emotional expression and speaker identity, enabling independent control over timbre and emotion. The model incorporates GPT latent representations and a three-stage training paradigm, with soft instruction mechanism based on text descriptions for emotional control, outperforming state-of-the-art models in word error rate, speaker similarity, and emotional fidelity.
IndexTTS-2: Advanced Emotional Voice Control
IndexTTS2 is a breakthrough auto-regressive zero-shot Text-to-Speech (TTS) model designed to address the challenge of precise duration control in large-scale TTS systems, which is a significant limitation in applications like video dubbing. It introduces a novel, general method for speech duration control, supporting two modes: one that explicitly specifies the number of generated tokens for precise duration, and another that generates speech freely in an auto-regressive manner. Furthermore, IndexTTS2 achieves disentanglement between emotional expression and speaker identity, enabling independent control over timbre and emotion via separate prompts. The model incorporates GPT latent representations and utilizes a novel three-stage training paradigm.
Pros
- Breakthrough zero-shot TTS with precise duration control.
- Independent control over timbre and emotional expression.
- GPT latent representations for enhanced speech clarity.
Cons
- Complex architecture may require advanced technical knowledge.
- Higher computational requirements for optimal performance.
Why We Love It
- It revolutionizes voice synthesis with independent emotional and speaker control, perfect for advanced applications like video dubbing and expressive voice generation.
Voice Synthesis Model Comparison
In this table, we compare 2025's leading open source voice synthesis models, each with unique strengths. For premium multilingual synthesis, Fish Speech V1.5 provides industry-leading performance. For real-time streaming applications, CosyVoice2-0.5B offers ultra-low latency. For advanced emotional control and zero-shot capabilities, IndexTTS-2 delivers breakthrough innovation. This side-by-side view helps you choose the right tool for your specific voice synthesis needs.
| Number | Model | Developer | Subtype | SiliconFlow Pricing | Core Strength |
|---|---|---|---|---|---|
| 1 | Fish Speech V1.5 | fishaudio | Text-to-Speech | $15/M UTF-8 bytes | Premium multilingual performance |
| 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 | Advanced emotional 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 text-to-speech synthesis, multilingual support, and advanced voice control capabilities.
Our analysis shows different leaders for specific needs. Fish Speech V1.5 is the top choice for premium multilingual applications requiring high accuracy. CosyVoice2-0.5B excels in real-time streaming scenarios with its 150ms latency. IndexTTS-2 is best for applications requiring precise emotional control and zero-shot voice cloning capabilities.