Empathic Voice Interface (EVI)

Vendor.com's Empathic Voice Interface (EVI) is the world's first emotionally intelligent voice AI.

Vendor.com's Empathic Voice Interface (EVI) is the world's first emotionally intelligent voice AI. It accepts live audio input and returns both generated audio and transcripts augmented with measures of vocal expression. By processing the tune, rhythm, and timbre of speech, EVI unlocks a variety of new capabilities, like knowing when to speak and generating more empathic language with the right tone of voice. These features enable smoother and more satisfying voice-based interactions between humans and AI, opening new possibilities for personal AI, customer service, accessibility, robotics, immersive gaming, VR experiences, and much more.

We provide a suite of tools to integrate and customize EVI for your organization.

Overview of EVI features

Empathic Voice Interface 2 (EVI 2)

Introducing EVI 2, our new voice-language foundation model, enabling human-like conversations with enhanced naturalness, emotional responsiveness, adaptability, and rich customization options for the voice and personality.

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 $0.1020 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.

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.

Configuring EVI

The Empathic Voice Interface (EVI) is designed to be highly configurable, allowing developers to customize the interface to align with their specific requirements. Configuration of EVI can be managed through two primary methods: an EVI configuration and session settings.

Configuration options

Default configuration options

EVI is pre-configured with a set of default values, which are automatically applied if you do not specify a configuration. The default configuration includes a preset voice and language model, but does not include a system prompt or tools. To customize these options, you will need to create and specify your own EVI configuration.

The default configuration settings are as follows:

Tool use

EVI simplifies the integration of external APIs through function calling. Developers can integrate custom functions that are invoked dynamically based on the user's input, enabling more useful conversations. There are two key concepts for using function calling with EVI: Tools and Configurations (Configs):

• Tools are resources that EVI uses to do things, like search the web or call external APIs. For example, tools can check the weather, update databases, schedule appointments, or take actions based on what occurs in the conversation. While the tools can be user-defined, Hume also offers natively implemented tools, like web search, which are labeled as “built-in” tools.
• Configurations enable developers to customize an EVI's behavior and incorporate these custom tools. Setting up an EVI configuration allows developers to seamlessly integrate their tools into the voice interface. A configuration includes prompts, user-defined tools, and other settings.

The focus of this guide is on creating a Tool and a Configuration that allows EVI to use the Tool. Additionally, this guide details the message flow of function calls within a session, and outlines the expected responses when function calls fail. Refer to our Configuration Guide for detailed, step-by-step instructions on how to create and use an EVI Configuration.

Voices

The Empathic Voice Interface (EVI) can be configured with any of our 8 base voices. You can also customize these voices by adjusting specific attributes. This guide explains each attribute and provides a tutorial for creating a custom voice. Visit the Playground to test the base voices.

Voice attributes

The following attributes can be modified to personalize any of the base voices:

Each voice attribute can be adjusted relative to the base voice's characteristics. Values range from -100 to 100, with 0 as the default. Setting all attributes to their default values will keep the base voice unchanged.