You can configure how your persona’s voice sounds — speed, volume, and emotion — via voiceGenerationOptions in the persona config. The available options depend on the provider and model of the configured voice.
const personaConfig = {
name: "Cara",
avatarId: "30fa96d0-26c4-4e55-94a0-517025942e18",
voiceId: "6bfbe25a-979d-40f3-a92b-5394170af54b",
llmId: "0934d97d-0c3a-4f33-91b0-5e136a0ef466",
systemPrompt: "You are Cara, a helpful customer service representative.",
voiceGenerationOptions: {
speed: 1.2,
volume: 0.8,
emotion: "content"
}
};
Cartesia voices
The following options are valid for Cartesia sonic-3 voices:
| Option | Range | Description |
|---|
volume | 0.5 – 2.0 | Multiplier to decrease or increase the volume of the original voice |
speed | 0.6 – 1.5 | Multiplier to decrease or increase the speed of the original voice |
emotion | string | Emotion to apply: neutral, calm, angry, content, sad, scared |
ElevenLabs voices
The following options are valid for ElevenLabs v1 and v2 voices:
| Option | Range | Description |
|---|
stability | 0 – 1 | How much the voice varies between generations. Lower values introduce more emotional variation |
similarityBoost | 0 – 1 | How closely the generated voice matches the original reference audio |
speed | 0.7 – 1.2 | Multiplier to decrease or increase the speed of the original voice |
v2 voices, these additional options are also available:
| Option | Type | Description |
|---|
useSpeakerBoost | boolean | Boost similarity to the original speaker. May increase latency |
style | 0 – 1 | How much the original speaker’s style is amplified. Values other than 0 may increase latency |
Changing voices
The voiceGenerationOptions are specific to the provider, model, and voice being used. When you change the voiceId for a persona, these options reset. Use the copy persona feature in Lab when experimenting with different voices to avoid losing your existing config. Last modified on April 14, 2026
