# Voice Changer
Source: https://docs.simpleserve.ai/docs/voice/voice-changer
Summary: Convert a recording into another voice, preset or cloned. ElevenLabs speech-to-speech shape. Billed per second of input audio.
Availability: available
Last reviewed: 2026-08-25

## Convert audio

`POST /elevenlabs/v1/speech-to-speech/{voice_id}` takes audio and returns the same speech in the target voice. `/stream` streams the result. `output_format` is a query parameter.

**Python**

```python
from elevenlabs.client import ElevenLabs

client = ElevenLabs(base_url="https://api.simpleserve.ai/elevenlabs", api_key="ss_live_your_key")

with open("me.wav", "rb") as f:
    audio = client.speech_to_speech.convert(voice_id="21m00Tcm4TlvDq8ikWAM", audio=f, model_id="eleven_english_sts_v2", output_format="mp3_44100_128")
with open("converted.mp3", "wb") as out:
    for chunk in audio:
        out.write(chunk)
```

**cURL**

```bash
curl "https://api.simpleserve.ai/elevenlabs/v1/speech-to-speech/21m00Tcm4TlvDq8ikWAM/stream?output_format=mp3_44100_128" \
  -H "Authorization: Bearer $SIMPLESERVE_API_KEY" \
  -F "audio=@me.wav" \
  -F "model_id=eleven_english_sts_v2" \
  --output converted.mp3
```

| Prop | Type | Required | Default | Description |
| --- | --- | --- | --- | --- |
| `audio` | `file` | yes |  | The source recording. |
| `model_id` | `string` | no | `"eleven_english_sts_v2"` | eleven_english_sts_v2 and eleven_multilingual_sts_v2 resolve to chatterbox-vc. |
| `voice_settings` | `string` | no |  | JSON object as a string. |
| `seed` | `integer` | no |  | Best-effort determinism. |
| `remove_background_noise` | `boolean` | no | `false` | Accepted for compatibility. Audio is used as uploaded. |

The target `voice_id` can be a preset voice or a [cloned voice](/docs/voice/voice-cloning).

## Pricing

Billed per second of input audio at the `chatterbox-vc` rate.

| Model | Model id | Price | Unit |
| --- | --- | --- | --- |
| Kokoro 82M | `kokoro-82m` | $3.00 per 1M characters | Input characters |
| Chatterbox | `chatterbox` | $6.00 per 1M characters | Input characters |
| Chatterbox Voice Conversion | `chatterbox-vc` | $0.060 per minute | Input audio, billed per second |