---
title: Voice Selection Guide [TTS]
slug: voice-selection-guide-tts
docTags: 
createdAt: 2026-01-23T11:07:51.675Z
---

## Overview

The UNITH interFace supports multiple text-to-speech (TTS) providers to give your Digital Human a natural, engaging voice. You can select voices from ElevenLabs or Microsoft Azure directly through the interface, or integrate custom voice providers using our connector framework. 

:::hint{type="info"}
Please check our [documentation](https://docs.unith.ai/voice-connectors) on Voice connectors that we support.

Need a different voice provider? You have full flexibility to create custom voice connectors. Please check out the following [repository.](https://github.com/unith-ai/voice-connector-template)
:::

***

## How Voice Selection Impacts Performance

Digital Human responses require audio generation before video synthesis can begin. The audio generation speed directly affects the overall response time of your Digital Human.

**Response Pipeline:**

1. User query processed
2. **Audio generated** ← Voice model speed matters here
3. Video synthesized from audio
4. Complete response delivered

:::hint{type="success"}
Faster audio generation means quicker responses and a more natural, engaging user experience.
:::

## Recommended Voices by Provider

### ElevenLabs

ElevenLabs offers a wide variety of voices powered by different models, each optimized for specific use cases. For Digital Human applications, we recommend using voices powered by their **speed-optimized models**.

**Recommended Models**

| **Model**    | **Characteristics**                  | **Use Case**                                  |
| ------------ | ------------------------------------ | --------------------------------------------- |
| `flash_v2`   | Fastest generation, balanced quality | Real-time conversations                       |
| `flash_v2_5` | Enhanced flash model                 | Real-time conversations with improved quality |
| `turbo_v2`   | High-speed generation                | Low-latency interactions                      |
| `turbo_v2_5` | Latest turbo generation              | Optimal balance of speed and quality          |



**Best Practice:** Select ElevenLabs voices that use `flash_v2, flash_v2_5, turbo_v2, or turbo_v2_5` models for the fastest Digital Human response times.

**Important Notes**

- All ElevenLabs models will function correctly with Digital Humans
- Non-optimized models may result in longer response delays
- Speed-optimized models are specifically designed for real-time conversational applications

:::hint{type="info"}
For a complete list of available voices and their associated models, [visit the ElevenLabs Voice Library.](https://elevenlabs.io/docs/overview/capabilities/voices)
:::

***

### Microsoft Azure

Microsoft Azure offers an extensive voice catalog across multiple performance tiers. For optimal Digital Human performance, we recommend selecting voices from their **speed-optimized tiers**.

**Recommended Voice Types**

Select voices that include one of these identifiers in their name:

| **Voice Type**         | **Identifier**    | **Language Support**             | **Performance**                              |
| ---------------------- | ----------------- | -------------------------------- | -------------------------------------------- |
| **Turbo Multilingual** | TurboMultilingual | 40+ languages                    | Fastest generation across multiple languages |
| **HD Flash**           | HDFlash           | English (US), Chinese (Mandarin) | Very fast with high-definition quality       |

**Voices to Avoid**

Avoid voices containing `HDNeural` in their name, as these prioritize audio quality over generation speed and will result in longer response times.

**Azure Voice Performance Tiers**

The table below provides an overview of Microsoft Azure's voice catalog organized by performance characteristics:

| **Performance Tier** | **Language Coverage**          | **Available Voices** | **Recommended **                      |
| -------------------- | ------------------------------ | -------------------- | ------------------------------------------ |
| **Turbo**            | English (US) only              | 7                    | ✅ Yes - Fastest option                     |
| **HD Flash**         | English (US), Mandarin Chinese | 10                   | ✅ Yes - Fast with HD quality               |
| **Multilingual**     | 40+ languages                  | 52                   | ✅ Yes - Best for multilingual applications |
| **HD Neural**        | Limited (10-15 languages)      | 54                   | ⚠️ Not recommended - Slower generation     |
| **Standard Neural**  | 150+ locales                   | 500+                 | ⚠️ Mixed performance                       |

:::hint{type="success"}
For multilingual Digital Humans, prioritize voices with `TurboMultilingual` in their name to maintain fast response times across all supported languages.
:::

:::hint{type="info"}
For the complete Azure voice catalog and detailed specifications, visit the [Microsoft Azure TTS Documentation.](https://learn.microsoft.com/en-us/azure/ai-services/speech-service/index-text-to-speech)
:::

***

## Voice Selection Best Practices

1. **Prioritize Speed-Optimized Models:** Choose voices specifically designed for low-latency applications
2. **Test Before Deploying:** Always test selected voices with your Digital Human to ensure they meet your quality and performance requirements
3. **Consider Your Audience:** Balance response speed with voice quality based on your use case
4. **Language Requirements:** If you need multilingual support, select voices that cover all required languages while maintaining performance