Models / Cartesia
Audio

Cartesia Sonic

Low-latency text-to-speech from Cartesia

About model

On Together AI, Cartesia Sonic costs $65.00 per 1M characters.

Sonic is Cartesia's original text-to-speech model, built on state space models to deliver natural, expressive speech with low latency for real-time applications. It converts text to high-quality audio for voice agents, conversational AI, and content narration. Available on Together AI.

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Latency

Low

Built on state space models for real-time speech

Voice Quality

Natural

Expressive, natural-sounding synthesis

Real-Time Output

Streaming

Suited to live voice applications

Model key capabilities
  • Low-Latency Speech: State space model architecture built for real-time voice generation
  • Natural Voices: Expressive, natural-sounding speech synthesis
  • Real-Time Applications: Designed for voice agents and conversational interfaces
  • Available on Together AI: Serverless access through the Together AI API
  • API usage

    • cURL
    • Python
    • Typescript

    Endpoint:

    cartesia/sonic

    curl --location 'https://api.together.ai/v1/audio/generations' \
      --header 'Content-Type: application/json' \
      --header 'Authorization: Bearer $TOGETHER_API_KEY' \
      --output speech.mp3 \
      --data '{
        "input": "Today is a wonderful day to build something people love!",
        "voice": "helpful woman",
        "response_format": "mp3",
        "sample_rate": 44100,
        "stream": false,
        "model": "cartesia/sonic"
      }'
    
    from together import Together
    
    client = Together()
    
    speech_file_path = "speech.mp3"
    
    response = client.audio.speech.create(
      model="cartesia/sonic",
      input="Today is a wonderful day to build something people love!",
      voice="helpful woman",
    )
        
    response.stream_to_file(speech_file_path)
    
    
    import Together from 'together-ai';
    
    const together = new Together();
    
    async function generateAudio() {
       const res = await together.audio.create({
        input: 'Today is a wonderful day to build something people love!',
        voice: 'helpful woman',
        response_format: 'mp3',
        sample_rate: 44100,
        stream: false,
        model: 'cartesia/sonic',
      });
    
      if (res.body) {
        console.log(res.body);
        const nodeStream = Readable.from(res.body as ReadableStream);
        const fileStream = createWriteStream('./speech.mp3');
    
        nodeStream.pipe(fileStream);
      }
    }
    
    generateAudio();
    
    
  • Model card

    Architecture Overview:
    • Text-to-speech model from Cartesia built on state space models
    • Text input with audio output

    Training Methodology:
    • Cartesia's first-generation Sonic model, predecessor to Sonic-2 and later releases

    Performance Characteristics:
    • Low-latency speech generation suited to real-time voice applications

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  • Prompting

    Together AI API Access:
    • Access Cartesia Sonic via Together AI APIs using the endpoint cartesia/sonic
    • Authenticate using your Together AI API key in request headers
    • Send text input to generate speech audio
    • Available on Together AI with serverless access

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  • Applications & use cases

    Voice Agents:
    • Power real-time conversational agents with low-latency speech
    • Voice customer service and support assistants
    • Add spoken responses to interactive apps

    Content Narration:
    • Narrate articles, documents, and audiobooks
    • Generate voiceover for video content
    • Produce spoken versions of written material

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  • Model provider
    Cartesia
  • Type
    Audio
  • Main use cases
    Text-to-Speech
  • Deployment
  • Price

    $65.00 / 1M characters

  • Input modalities
    Text
  • Output modalities
    Audio
  • Category
    Audio