> ## Documentation Index
> Fetch the complete documentation index at: https://blackbox.dasha.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# TTS Providers Reference

> Detailed configuration for ElevenLabs, Cartesia, Inworld, and LMNT text-to-speech providers.

Detailed configuration for each TTS provider. For basic setup, see [Voice & Speech](/docs/create/voice-and-speech).

***

## ElevenLabs

Industry-leading voice quality with extensive customization. [Browse voices →](https://elevenlabs.io/app/voice-library)

**Models:**

* `eleven_multilingual_v2` — Best quality, 29+ languages
* `eleven_turbo_v2_5` — Balanced speed and quality
* `eleven_flash_v2_5` — Fastest inference

**Speed range:** 0.70x to 1.20x

### Configuration options

| Option                       | Range   | Default | Effect                                |
| ---------------------------- | ------- | ------- | ------------------------------------- |
| `similarity_boost`           | 0.0–1.0 | 0.75    | Voice consistency with original       |
| `stability`                  | 0.0–1.0 | 0.5     | Output consistency across generations |
| `style`                      | 0.0–1.0 | 0.3     | Speaker style exaggeration            |
| `use_speaker_boost`          | boolean | true    | Enhanced clarity                      |
| `optimize_streaming_latency` | 0–4     | 4       | Trade quality for speed               |

### Example

<Accordion title="ElevenLabs configuration example">
  ```javascript theme={"theme":{"light":"github-light","dark":"github-dark"}}
  ttsConfig: {
    vendor: "ElevenLabs",
    voiceId: "21m00Tcm4TlvDq8ikWAM",
    model: "eleven_turbo_v2_5",
    speed: 1.0,
    vendorSpecificOptions: {
      similarity_boost: 0.8,
      stability: 0.6,
      style: 0.4,
      use_speaker_boost: true,
      optimize_streaming_latency: 3
    }
  }
  ```
</Accordion>

***

## Cartesia

Granular emotion control with wide speed range. [Browse voices →](https://play.cartesia.ai/)

**Models:**

* `sonic-3.5` — Latest generation (recommended)

**Speed range:** 0x to 2.0x (values below 0.25x sent as 0.25x)

### Emotion system

Combine emotions for nuanced delivery:

| Dimension  | Intensities                |
| ---------- | -------------------------- |
| anger      | lowest, low, high, highest |
| positivity | lowest, low, high, highest |
| surprise   | lowest, low, high, highest |
| sadness    | lowest, low, high, highest |
| curiosity  | lowest, low, high, highest |

<Tip>
  Start with subtle emotions (`low` levels). Combining too many high-intensity emotions sounds unnatural.
</Tip>

### Example

<Accordion title="Cartesia configuration example">
  ```javascript theme={"theme":{"light":"github-light","dark":"github-dark"}}
  ttsConfig: {
    vendor: "Cartesia",
    voiceId: "cartesia-voice-id",
    model: "sonic-3.5",
    speed: 1.2,
    vendorSpecificOptions: {
      emotions: [
        "positivity:high",
        "curiosity:low"
      ]
    }
  }
  ```
</Accordion>

***

## Inworld

Character-focused voices for gaming and interactive media. [Browse voices →](https://platform.inworld.ai/)

**Models:**

* `inworld-tts-1.5-max` — Highest quality
* `inworld-tts-1.5-mini` — Balanced speed and quality (recommended)
* `inworld-tts-1` — Original model

**Speed range:** 0.80x to 1.50x

### Configuration options

| Option        | Default | Effect                 |
| ------------- | ------- | ---------------------- |
| `temperature` | 0.8     | Voice expressiveness   |
| `pitch`       | 0.0     | Pitch adjustment (+/-) |

### Example

<Accordion title="Inworld configuration example">
  ```javascript theme={"theme":{"light":"github-light","dark":"github-dark"}}
  ttsConfig: {
    vendor: "Inworld",
    voiceId: "inworld-voice-id",
    model: "inworld-tts-1.5-mini",
    speed: 1.0,
    vendorSpecificOptions: {
      temperature: 0.9,
      pitch: 0.2
    }
  }
  ```
</Accordion>

***

## LMNT

Consistent, lightweight synthesis. [Browse voices →](https://app.lmnt.com/)

**Models:**

* `blizzard` — Standard model

**Speed range:** Fixed at 1.0x (no adjustment)

### Example

<Accordion title="LMNT configuration example">
  ```javascript theme={"theme":{"light":"github-light","dark":"github-dark"}}
  ttsConfig: {
    vendor: "Lmnt",
    voiceId: "lmnt-voice-id",
    model: "blizzard"
  }
  ```
</Accordion>

<Note>
  LMNT does not support speed adjustment. Voice always plays at 1.0x.
</Note>

***

## Advanced settings

### Responsiveness

Controls how quickly the agent begins speaking after the user finishes.

| Value   | Behavior                                      |
| ------- | --------------------------------------------- |
| **1.0** | Most responsive — minimal delay (recommended) |
| **0.7** | Slight delay added                            |
| **0.5** | Moderate delay                                |
| **0.0** | Maximum delay                                 |

<Accordion title="Responsiveness configuration example">
  ```javascript theme={"theme":{"light":"github-light","dark":"github-dark"}}
  ttsConfig: {
    responsiveness: 1.0
  }
  ```
</Accordion>

### Interruption sensitivity

Controls how easily users can interrupt the agent while it is speaking. Lower values require more user speech before the agent stops; higher values make it easier to cut in.

| Value   | Behavior                                                          |
| ------- | ----------------------------------------------------------------- |
| **1.0** | Easiest to interrupt — agent yields quickly (default)             |
| **0.5** | Moderate — more user speech required before the agent stops       |
| **0.0** | Non-interruptible — the agent is not interrupted by normal speech |

When left unset, the agent uses its default interruptible behavior (equivalent to `1.0`).

<Accordion title="Interruption sensitivity configuration example">
  ```javascript theme={"theme":{"light":"github-light","dark":"github-dark"}}
  ttsConfig: {
    interruptionSensitivity: 1.0
  }
  ```
</Accordion>

### Dynamic speed adjustment

Allow agents to adapt speech pace when users request it ("Can you speak more slowly?").

<Accordion title="Speed adjustment configuration example">
  ```javascript theme={"theme":{"light":"github-light","dark":"github-dark"}}
  ttsConfig: {
    speed: 1.0,
    speedAdjustment: {
      version: "v1",
      strategy: "OnRequest"  // or "Disabled"
    }
  }
  ```
</Accordion>

| Strategy    | Behavior                                         |
| ----------- | ------------------------------------------------ |
| `OnRequest` | Agent adjusts speed when user requests (default) |
| `Disabled`  | Speed remains fixed                              |

***

## Speed ranges by provider

| Provider   | Min                | Max   | Default | Recommended  |
| ---------- | ------------------ | ----- | ------- | ------------ |
| ElevenLabs | 0.70x              | 1.20x | 1.0x    | 0.9x–1.2x    |
| Cartesia   | 0x (sent as 0.25x) | 2.0x  | 1.0x    | 0.8x–1.3x    |
| Inworld    | 0.80x              | 1.50x | 1.0x    | 0.9x–1.1x    |
| LMNT       | 1.0x               | 1.0x  | 1.0x    | 1.0x (fixed) |

***

## Provider decision guide

**Choose ElevenLabs if:**

* You need highest voice quality
* Brand-specific voice cloning is important
* Advanced customization is required

**Choose Cartesia if:**

* Emotional expression is important
* You need wide speed range (0x-2.0x)

**Choose Inworld if:**

* You're building character-driven experiences
* Gaming or interactive media is your use case

**Choose LMNT if:**

* You need consistent, predictable output
* Minimal configuration is desired

***

## Pronunciation dictionary

Customize how your agent pronounces brand names, acronyms, and technical terms.

### Provider support

| Provider   | Alias rules | Phoneme rules |
| ---------- | ----------- | ------------- |
| ElevenLabs | Yes         | No            |
| Cartesia   | Yes         | Yes           |
| Inworld    | No          | No            |
| LMNT       | No          | No            |

**Alias rules** replace one word with another spelling. **Phoneme rules** specify exact pronunciation using IPA notation.

### Create a dictionary

<Accordion title="API example: Create pronunciation dictionary">
  ```javascript theme={"theme":{"light":"github-light","dark":"github-dark"}}
  const response = await fetch('https://blackbox.dasha.ai/api/v1/pronunciation-dictionaries', {
    method: 'POST',
    headers: {
      'Authorization': 'Bearer YOUR_API_KEY',
      'Content-Type': 'application/json'
    },
    body: JSON.stringify({
      name: "Company Terms",
      provider: "Cartesia",
      rules: [
        {
          type: "alias",
          stringToReplace: "API",
          replacement: "A P I"
        },
        {
          type: "alias",
          stringToReplace: "SQL",
          replacement: "sequel"
        },
        {
          type: "phoneme",
          stringToReplace: "Dasha",
          phoneme: "ˈdɑːʃə",
          alphabet: "ipa"
        }
      ]
    })
  });

  const dictionary = await response.json();
  console.log('Dictionary ID:', dictionary.id);
  // Output: pd_abc123def456
  ```
</Accordion>

### Reference in agent config

<Accordion title="Pronunciation dictionary reference example">
  ```javascript theme={"theme":{"light":"github-light","dark":"github-dark"}}
  ttsConfig: {
    vendor: "Cartesia",
    voiceId: "your-voice-id",
    pronunciationDictionary: {
      id: "pd_abc123def456",
      hash: "a1b2c3d4e5f6"
    }
  }
  ```
</Accordion>

<Tip>
  Create a single, comprehensive dictionary for your organization and reference it across all agents.
</Tip>

***

## Multilingual configuration

For agents that switch languages mid-conversation:

<Accordion title="Multilingual configuration example">
  ```javascript theme={"theme":{"light":"github-light","dark":"github-dark"}}
  config: {
    primaryLanguage: "en-US",
    ttsConfig: {
      version: "v1",
      vendor: "ElevenLabs",
      voiceId: "multilingual-voice-id",
      model: "eleven_multilingual_v2",
      speed: 1.0
    },
    features: {
      languageSwitching: {
        isEnabled: true
      }
    }
  }
  ```
</Accordion>

***

## Related

<CardGroup cols={2}>
  <Card title="Voice & Speech" icon="volume-high" href="/docs/create/voice-and-speech">
    Basic voice configuration
  </Card>

  <Card title="Dashboard Testing" icon="play" href="/docs/test/dashboard-testing">
    Test voice quality in the browser
  </Card>
</CardGroup>