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

EVI configuration options affect the behavior and capabilities of the interface, and include the following 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:

Create a configuration

See instructions below for creating an EVI configuration through the Portal. In the Portal, navigate to the EVI Configurations page. Click the Create configuration button to begin.

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Choose EVI version

To learn more about the differences between EVI versions 1 and 2, please see the feature comparison guide.

2

Choose voice

Select a voice from Hume’s 8 presets, or create your own custom voice. To learn more about voice customization options on the Hume Platform, please visit the Voices page.

3

Set up the LLM

Select a supported language model and specify a system prompt.

4

Add tools

Equip EVI with built-in tools, like web search, or custom user-defined tools. Click the + Add button to select an existing tool or create a new one.

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Name config

Name your EVI configuration and add an optional description.

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Test the configuration

The newly created configuration can now be tested. From the EVI Config details page, click Run in playground to test it out.

Once in the EVI Playground, click Start call to connect to EVI with your configuration.

The event message and timeout configuration options are not part of the initial config creation flow. However, you can set these options at any time in the playground or from the configuration’s edit page after your configuration has been created.

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Apply the configuration

After creating an EVI configuration, you can use it in your conversations with EVI by including the config_id in the query parameters of your connection request. You can find the config_id on the configuration’s edit page. To access this page, first navigate to the configurations page and then click the Edit button for the desired configuration.

See the sample code below which showcases how to apply your configuration:

TypeScriptPython

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import { Hume, HumeClient } from 'hume';
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// instantiate the HumeClient with credentials
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// avoid hard coding your API key, retrieve from environment variables
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const client = new HumeClient({
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  apiKey: <YOUR_API_KEY>,
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  secretKey: <YOUR_SECRET_KEY>,
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});
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// instantiate WebSocket connection with specified EVI config
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const socket = await client.empathicVoice.chat.connect({
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  configId: <YOUR_CONFIG_ID> // specify config ID here
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});

Session settings

EVI configurations are persistent and version-controlled. In contrast, session settings are temporary and apply only to the current session, such as microphone settings. These parameters can be adjusted dynamically based on the requirements of each session to ensure optimal performance and user experience.

Updating the session settings is only a requirement when the audio input is encoded in PCM Linear 16. If this is the case, be sure to send the following Session Settings message prior to sending an audio input:

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{
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  "type": "session_settings",
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  "audio": {
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    "channels": 1,
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    "encoding": "linear16",
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    "sample_rate": 48000
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  }
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}