Empathic Voice Interface 2 (EVI 2)

The Empathic Voice Interface 2 (EVI 2) introduces a new architecture that seamlessly integrates voice and language processing. This multimodal approach allows EVI 2 to understand and generate both language and voice, dramatically enhancing key features over EVI 1 while also enabling new capabilities.

EVI 2 can converse rapidly and fluently with users, understand a user’s tone of voice, generate any tone of voice, and can even handle niche requests like rapping, changing its style, or speeding up its speech. The model specifically excels at emulating a wide range of personalities, including their accents and speaking styles. It is exceptional at maintaining personalities that are fun and interesting to interact with. Ultimately, EVI 2 is capable of emulating the ideal personality for every application and user.

In addition, EVI 2 allows developers to create custom voices by using a new voice modulation method. Developers can adjust EVI 2’s base voices along a number of continuous scales, including gender, nasality, and pitch. This first-of-its-kind feature enables creating voices that are unique to an application or even a single user. Further, this feature does not rely on voice cloning, which currently invokes more risks than any other capability of this technology.

Key improvements

1. Improved voice quality: EVI 2 uses an advanced voice generation model connected to our eLLM, which can process and generate both text and audio. This results in more natural-sounding speech with better word emphasis, higher expressiveness, and more consistent vocal output.

2. Faster responses: The integrated architecture of EVI 2 reduces end-to-end latency by 40% vs EVI 1, now averaging around 500ms. This significant speed improvement enables more responsive and human-like conversations.

3. Enhanced emotional intelligence: By processing voice and language in the same model, EVI 2 can better understand the emotional context of user inputs and generate more empathic responses, both in terms of content and vocal tone.

4. Custom voices and personality: EVI 2 offers new control over the AI’s voice characteristics. Developers can adjust various parameters to tailor EVI 2’s voice to their specific application needs. EVI 2 also supports in-conversation voice prompting, allowing users to dynamically modify EVI’s speaking style (e.g., “speak faster”, “sound excited”) during interactions.

5. Cost-effectiveness: Despite its advanced capabilities, EVI 2 is 30% more cost-effective than its predecessor, with pricing reduced from $0.102 to $0.0714 per minute.

Beyond these improvements, EVI 2 also exhibits promising emerging capabilities including speech output in multiple languages. We will make these improvements available to developers as we scale up and improve the model.

We provide the same suite of tools to integrate and customize EVI 2 for your application as we do for EVI 1, and existing EVI developers can easily switch to the new system.

Building with EVI 2

Developers can start testing EVI 2 by simply creating an EVI config on the Hume platform. Just select EVI 2 as the version when creating your config.

To use EVI 2, simply create a configuration using the /v0/evi/configs endpoint and specify "evi_version": "2". Then, use this config in a conversation with EVI using the /v0/evi/chat endpoint. Most aspects of using EVI, including authentication strategies, remain the same as described in the EVI documentation.

1. In your configuration JSON, set the evi_version parameter to "2". Here’s an example of an EVI 2 config:

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{
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  "evi_version": "2",
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  "name": "EVI 2 config",
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  "voice": {
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    "provider": "HUME_AI",
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    "name": "DACHER"
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  }
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}

2. Using a config like the above, make a POST request to the /v0/evi/configs endpoint to save the config.
3. Specify any other custom settings you need.

EVI 2 timeline

EVI 2 is available now, with full feature parity with EVI 1, including support for supplemental LLMs, custom language models, tool use, built-in tools like web search, and all configuration options.

From September to December 2024, the Hume team will focus on improving the reliability and quality of EVI 2. The team will ensure that all the features of the EVI 1 API work consistently in EVI 2.

In late December 2024, the EVI 1 API will be sunsetted and deprecated. Developers will need to migrate from EVI 1 to EVI 2 for ongoing support and new features.

Feature comparison: EVI 1 vs EVI 2

This table provides a comprehensive comparison of features between EVI 1 and EVI 2, highlighting the new capabilities introduced in the latest version.

Frequently Asked Questions