@mastra/core/dist/docs/references/reference-voice-composite-voice.md

Mastra is a framework for building AI-powered applications and agents with a modern TypeScript stack.

# CompositeVoice

The CompositeVoice class allows you to combine different voice providers for text-to-speech and speech-to-text operations. This is particularly useful when you want to use the best provider for each operation - for example, using OpenAI for speech-to-text and PlayAI for text-to-speech.

CompositeVoice supports both Mastra voice providers and AI SDK model providers

## Constructor parameters

**config** (`object`): Configuration object for the composite voice service

**config.input** (`MastraVoice | TranscriptionModel`): Voice provider or AI SDK transcription model to use for speech-to-text operations. AI SDK models are automatically wrapped.

**config.output** (`MastraVoice | SpeechModel`): Voice provider or AI SDK speech model to use for text-to-speech operations. AI SDK models are automatically wrapped.

**config.realtime** (`MastraVoice`): Voice provider to use for real-time speech-to-speech operations

## Methods

### `speak()`

Converts text to speech using the configured speaking provider.

**input** (`string | NodeJS.ReadableStream`): Text to convert to speech

**options** (`object`): Provider-specific options passed to the speaking provider

Notes:

- If no speaking provider is configured, this method will throw an error
- Options are passed through to the configured speaking provider
- Returns a stream of audio data

### `listen()`

Converts speech to text using the configured listening provider.

**audioStream** (`NodeJS.ReadableStream`): Audio stream to convert to text

**options** (`object`): Provider-specific options passed to the listening provider

Notes:

- If no listening provider is configured, this method will throw an error
- Options are passed through to the configured listening provider
- Returns either a string or a stream of transcribed text, depending on the provider

### `getSpeakers()`

Returns a list of available voices from the speaking provider, where each node contains:

**voiceId** (`string`): Unique identifier for the voice

**key** (`value`): Additional voice properties that vary by provider (e.g., name, language)

Notes:

- Returns voices from the speaking provider only
- If no speaking provider is configured, returns an empty array
- Each voice object will have at least a voiceId property
- Additional voice properties depend on the speaking provider

## Usage examples

### Using Mastra Voice Providers

```typescript
import { CompositeVoice } from '@mastra/core/voice'
import { OpenAIVoice } from '@mastra/voice-openai'
import { PlayAIVoice } from '@mastra/voice-playai'

// Create voice providers
const openai = new OpenAIVoice()
const playai = new PlayAIVoice()

// Use OpenAI for listening (speech-to-text) and PlayAI for speaking (text-to-speech)
const voice = new CompositeVoice({
  input: openai,
  output: playai,
})

// Convert speech to text using OpenAI
const text = await voice.listen(audioStream)

// Convert text to speech using PlayAI
const audio = await voice.speak('Hello, world!')
```

### Using AI SDK Model Providers

You can pass AI SDK transcription and speech models directly to CompositeVoice:

```typescript
import { CompositeVoice } from '@mastra/core/voice'
import { openai } from '@ai-sdk/openai'
import { elevenlabs } from '@ai-sdk/elevenlabs'

// Use AI SDK models directly - they will be auto-wrapped
const voice = new CompositeVoice({
  input: openai.transcription('whisper-1'), // AI SDK transcription
  output: elevenlabs.speech('eleven_turbo_v2'), // AI SDK speech
})

// Works the same way as with Mastra providers
const text = await voice.listen(audioStream)
const audio = await voice.speak('Hello from AI SDK!')
```

### Mix and Match

You can combine Mastra providers with AI SDK models:

```typescript
import { CompositeVoice } from '@mastra/core/voice'
import { PlayAIVoice } from '@mastra/voice-playai'
import { groq } from '@ai-sdk/groq'

const voice = new CompositeVoice({
  input: groq.transcription('whisper-large-v3'), // AI SDK for STT
  output: new PlayAIVoice(), // Mastra for TTS
})
```