What are Open Source Audio Enhancement Models?
Open source audio enhancement models are specialized AI systems designed to improve, generate, and synthesize high-quality audio content from text descriptions. Using advanced deep learning architectures like dual autoregressive transformers and large language models, they translate natural language into realistic speech with precise control over emotions, duration, and multilingual capabilities. These models democratize access to professional-grade audio synthesis tools, enabling developers and creators to build innovative applications ranging from voice assistants to video dubbing with unprecedented quality and flexibility.
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. Supporting multiple languages with over 300,000 hours of training data for English and Chinese, and over 100,000 hours for Japanese, it achieved an exceptional ELO score of 1339 in TTS Arena evaluations. The model delivers outstanding accuracy with a 3.5% word error rate for English and 1.2% character error rate.
Fish Speech V1.5: Multilingual Excellence in Audio 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. Supporting multiple languages with over 300,000 hours of training data for English and Chinese, and over 100,000 hours for Japanese, it achieved an exceptional ELO score of 1339 in TTS Arena evaluations. The model delivers outstanding accuracy with a 3.5% word error rate for English and 1.2% character error rate, making it ideal for professional audio enhancement applications requiring high-quality multilingual speech synthesis.
Pros
- Innovative DualAR architecture for superior audio quality.
- Extensive multilingual support with 300,000+ hours training data.
- Exceptional TTS Arena performance with 1339 ELO score.
Cons
- Higher SiliconFlow pricing at $15/M UTF-8 bytes.
- May require technical expertise for optimal implementation.
Why We Love It
- It delivers industry-leading multilingual TTS performance with innovative architecture, making it the gold standard for professional audio enhancement applications.
CosyVoice2-0.5B
CosyVoice 2 is a streaming speech synthesis model based on large language models, featuring a unified streaming/non-streaming framework. It achieves ultra-low latency of 150ms in streaming mode while maintaining synthesis quality identical to non-streaming mode. Compared to version 1.0, pronunciation error rates are reduced by 30%-50%, MOS scores improved from 5.4 to 5.53, with fine-grained control over emotions and dialects across Chinese, English, Japanese, and Korean.
CosyVoice2-0.5B: Ultra-Low Latency Streaming Audio Enhancement
CosyVoice 2 is a streaming speech synthesis model based on large language models, featuring a unified streaming/non-streaming framework design. The model enhances speech token codebook utilization through finite scalar quantization (FSQ) and develops chunk-aware causal streaming. It achieves ultra-low latency of 150ms in streaming mode while maintaining synthesis quality identical to non-streaming mode. Compared to version 1.0, pronunciation error rates are reduced by 30%-50%, MOS scores improved from 5.4 to 5.53, with fine-grained control over emotions and dialects across Chinese (including Cantonese, Sichuan, Shanghainese, Tianjin dialects), English, Japanese, and Korean, supporting cross-lingual scenarios.
Pros
- Ultra-low latency of 150ms for real-time applications.
- 30%-50% reduction in pronunciation error rates.
- Improved MOS score from 5.4 to 5.53.
Cons
- Smaller 0.5B parameter model compared to larger alternatives.
- Primarily optimized for streaming use cases.
Why We Love It
- It perfectly balances ultra-low latency with exceptional quality, making it ideal for real-time audio enhancement applications requiring instant response.
IndexTTS-2
IndexTTS2 is a breakthrough auto-regressive zero-shot Text-to-Speech model addressing precise duration control challenges in large-scale TTS systems. It features novel 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, with enhanced speech clarity through GPT latent representations and three-stage training.
IndexTTS-2: Advanced Zero-Shot Audio Control
IndexTTS2 is a breakthrough auto-regressive zero-shot Text-to-Speech model designed to address precise duration control challenges in large-scale TTS systems, particularly for video dubbing applications. It introduces novel speech duration control supporting 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. Enhanced speech clarity is achieved through GPT latent representations and a three-stage training paradigm. Features include soft instruction mechanism based on text descriptions using fine-tuned Qwen3, outperforming state-of-the-art zero-shot TTS models in word error rate, speaker similarity, and emotional fidelity.
Pros
- Precise duration control for video dubbing applications.
- Independent control over timbre and emotional expression.
- Zero-shot capabilities with superior performance metrics.
Cons
- More complex setup due to advanced control features.
- Both input and output pricing at $7.15/M UTF-8 bytes on SiliconFlow.
Why We Love It
- It revolutionizes audio enhancement with precise duration control and emotional disentanglement, perfect for professional video dubbing and advanced audio production workflows.
Audio Enhancement Model Comparison
In this table, we compare 2025's leading open source audio enhancement models, each with unique strengths. For multilingual excellence, Fish Speech V1.5 provides industry-leading performance. For real-time applications, CosyVoice2-0.5B offers unmatched ultra-low latency, while IndexTTS-2 prioritizes advanced emotional control and duration precision. This side-by-side view helps you choose the right tool for your specific audio enhancement goals.
| Number | Model | Developer | Subtype | SiliconFlow Pricing | Core Strength |
|---|---|---|---|---|---|
| 1 | Fish Speech V1.5 | fishaudio | Text-to-Speech | $15/M UTF-8 bytes | Multilingual TTS excellence |
| 2 | CosyVoice2-0.5B | FunAudioLLM | Text-to-Speech | $7.15/M UTF-8 bytes | Ultra-low latency streaming |
| 3 | IndexTTS-2 | IndexTeam | Audio | $7.15/M UTF-8 bytes | Zero-shot 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, streaming audio generation, and advanced emotional control in audio enhancement.
Our analysis shows different leaders for various needs. Fish Speech V1.5 excels for multilingual professional audio synthesis with its 1339 ELO score. CosyVoice2-0.5B is ideal for real-time applications requiring 150ms ultra-low latency. IndexTTS-2 is perfect for advanced use cases like video dubbing where precise duration control and emotional expression are crucial.