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Dia 2

Default

Standard English Neutral Dia 2

Default is a neutral AI voice powered by the Dia 2 text-to-speech model. This standard-tier voice speaks English and delivers high-quality speech synthesis. With near-instant generation speed and a quality rating of 4/5, Default is well-suited for real-time voice agents, dialogue generation, streaming applications. The Dia 2 engine is developed by Nari Labs under the Apache 2.0 license, making it safe for commercial use. Key capabilities include: streaming output, multi-speaker, low latency, paralinguistic cues, up to 2 min output.

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Dia 2Model Information

Model Dia 2
Developer Nari Labs
Quality
Speed Fast
License Apache 2.0
Cloning Not available
Tier Standard (2x characters)
Parameters 2B
Architecture Streaming Transformer
Year 2025

Best Use Cases for Default

Recommended applications based on this voice's characteristics

Audiobooks & Narration

Use Default to narrate long-form content with natural prosody and expression.

Video Voiceovers

Add professional narration to YouTube videos, ads, and social media content.

Apps & Accessibility

Fast generation makes this voice ideal for real-time apps, screen readers, and accessibility tools.

E-Learning & Training

Create engaging training materials, courses, and educational content with clear AI narration.

Frequently Asked Questions

Dia2 by Nari Labs is a streaming-first upgrade to Dia, available in 1B and 2B parameter variants. It begins synthesizing audio from the first few tokens, making it ideal for real-time voice agents and speech-to-speech pipelines. Supports multi-speaker dialogue with [S1]/[S2] tags and paralinguistic cues like (laughs), (coughs).

Dia 2 was developed by Nari Labs and is released under the Apache 2.0 license, which permits commercial use of generated audio.

Dia 2 supports 1 language: English.

Dia 2 is in the Standard tier — 2 credits per 1,000 characters. You can preview any Dia 2 voice for free before generating full audio.

Dia 2 has very fast generation speed. It runs in near real-time, making it suitable for streaming and interactive applications.

Dia 2 is rated 4/5 for audio quality on TTS.ai. It produces high-quality, natural-sounding speech.

No, Dia 2 uses a fixed set of built-in voices. For voice cloning, try models like CosyVoice 2, GPT-SoVITS, or Chatterbox.

Yes, Dia 2 is specifically recommended for real-time voice agents, dialogue generation, streaming applications. Its streaming output, multi-speaker, low latency capabilities make it an excellent choice for this use case.

Yes, Dia 2 is licensed under Apache 2.0, which allows commercial use. Audio generated with Dia 2 voices can be used in videos, podcasts, apps, games, and any other commercial project.

Yes, all voices on TTS.ai use commercially-licensed open-source models (MIT, Apache 2.0). The generated audio is yours to use in videos, podcasts, apps, games, and any other commercial application.

Send a POST request to /api/v1/tts/ with the model name and voice ID. See our API Documentation page for code examples in Python, JavaScript, Go, and cURL.

Yes, click the play button on this page to hear a sample. You can also type custom text on the Text to Speech page and generate a free preview with any voice.

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Type any text and hear it spoken by Default. Free to use.

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