What are Open Source Models for Sound Design?
Open source models for sound design are specialized AI systems that create, synthesize, and manipulate audio content from text descriptions or other inputs. Using advanced deep learning architectures like dual autoregressive transformers and large language models, they translate natural language prompts into high-quality speech, sound effects, and audio content. This technology allows sound designers, developers, and creators to generate, modify, and build upon audio ideas with unprecedented freedom. They foster collaboration, accelerate innovation, and democratize access to powerful audio creation tools, enabling a wide range of applications from voice acting and dubbing to interactive media and enterprise audio 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 independent TTS Arena evaluations, it achieved an exceptional ELO score of 1339, with outstanding accuracy rates: 3.5% WER and 1.2% CER for English, and 1.3% CER for Chinese characters.
Fish Speech V1.5: Multilingual Excellence in TTS
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 TTS Arena evaluations, it achieved an exceptional ELO score of 1339, with outstanding accuracy rates: 3.5% WER and 1.2% CER for English, and 1.3% CER for Chinese characters, making it ideal for professional sound design projects requiring multilingual audio content.
Pros
- Innovative DualAR architecture with dual autoregressive design.
- Exceptional multilingual support with extensive training data.
- Top-tier performance with 1339 ELO score in TTS Arena.
Cons
- Higher pricing at $15/M UTF-8 bytes on SiliconFlow.
- May require technical expertise for optimal implementation.
Why We Love It
- It delivers exceptional multilingual TTS performance with innovative architecture, making it perfect for professional sound design projects requiring high-quality, accurate speech synthesis across multiple languages.
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 while maintaining exceptional synthesis quality. Compared to version 1.0, pronunciation error rates are reduced by 30%-50%, MOS score improved from 5.4 to 5.53, with fine-grained control over emotions and dialects. Supports Chinese dialects, English, Japanese, Korean, and cross-lingual scenarios.
CosyVoice2-0.5B: Ultra-Low Latency Streaming TTS
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 while maintaining exceptional synthesis quality. The model enhances speech token codebook utilization through finite scalar quantization (FSQ) and develops chunk-aware causal streaming. Compared to version 1.0, pronunciation error rates are reduced by 30%-50%, MOS score improved from 5.4 to 5.53, with fine-grained control over emotions and dialects. Supports Chinese dialects, English, Japanese, Korean, and cross-lingual scenarios.
Pros
- Ultra-low latency of 150ms with maintained quality.
- 30%-50% reduction in pronunciation error rates.
- Improved MOS score from 5.4 to 5.53.
Cons
- Smaller 0.5B parameter size compared to larger models.
- Streaming focus may not suit all sound design applications.
Why We Love It
- It combines ultra-low latency streaming with exceptional quality and emotional control, perfect for real-time sound design applications and interactive audio experiences.
IndexTTS-2
IndexTTS2 is a breakthrough auto-regressive zero-shot Text-to-Speech model designed for precise duration control, addressing key limitations in applications like video dubbing. It features disentanglement between emotional expression and speaker identity, enabling independent control over timbre and emotion. The model incorporates GPT latent representations and uses a three-stage training paradigm, with soft instruction mechanism for emotional control based on text descriptions.
IndexTTS-2: Precision Control for Professional Audio
IndexTTS2 is a breakthrough auto-regressive zero-shot Text-to-Speech model designed for precise duration control, addressing key limitations in applications like video dubbing. It introduces novel speech duration control methods 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, uses a three-stage training paradigm, and features soft instruction mechanism based on text descriptions for emotional guidance.
Pros
- Breakthrough zero-shot TTS with precise duration control.
- Independent control over timbre and emotional expression.
- Superior performance in word error rate and speaker similarity.
Cons
- Complex architecture may require advanced technical knowledge.
- Both input and output pricing at $7.15/M UTF-8 bytes on SiliconFlow.
Why We Love It
- It revolutionizes professional sound design with precise duration control and independent emotional/timbre manipulation, making it ideal for video dubbing and complex audio production workflows.
AI Sound Design Model Comparison
In this table, we compare 2025's leading open-source sound design models, each with unique strengths. Fish Speech V1.5 excels in multilingual accuracy, CosyVoice2-0.5B offers ultra-low latency streaming, while IndexTTS-2 provides breakthrough duration control. This side-by-side view helps you choose the right tool for your specific sound design or audio production goal.
| Number | Model | Developer | Subtype | SiliconFlow Pricing | Core Strength |
|---|---|---|---|---|---|
| 1 | Fish Speech V1.5 | fishaudio | Text-to-Speech | $15/M UTF-8 bytes | Multilingual excellence & accuracy |
| 2 | CosyVoice2-0.5B | FunAudioLLM | Text-to-Speech | $7.15/M UTF-8 bytes | Ultra-low latency streaming |
| 3 | IndexTTS-2 | IndexTeam | Audio Generation | $7.15/M UTF-8 bytes | Precise duration & emotion control |
Frequently Asked Questions
Our top three picks for sound design in 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, audio generation, and professional sound design applications.
Our analysis shows different leaders for specific needs: Fish Speech V1.5 is ideal for multilingual projects requiring high accuracy, CosyVoice2-0.5B excels in real-time streaming applications with its 150ms latency, and IndexTTS-2 is perfect for video dubbing and professional audio production requiring precise duration and emotional control.