> ## Documentation Index
> Fetch the complete documentation index at: https://docs.snapgen.org/llms.txt
> Use this file to discover all available pages before exploring further.

# Eleven English STS v2

> Re-voice English speech with an ElevenLabs premade voice. $0.18 per minute.

`eleven-english-sts-v2` is the English speech-to-speech voice changer: it re-voices an English recording with one of the premade voices and returns the new audio in the response. Use [`eleven-multilingual-sts-v2`](/api-manual/audio/eleven-multilingual-sts-v2) for other languages.

| Property | Value |
| - | - |
| Model ID | `eleven-english-sts-v2` |
| Endpoint | `POST /v1/audio/voice-changer` (multipart file or JSON `audio_url`) |
| Output | Audio bytes: MP3 (default), Opus, PCM, or WAV |
| Limits | Input up to 300 seconds, up to 50 MB |
| Billed on | Input length measured by SnapGen, in whole seconds |
| Price | \$0.003 per second (\$0.18 per minute, 0.3 credits per second) |

Confirm live rates on the [SnapGen models page](https://snapgen.org/models). Failed requests are not charged.

<ParamField body="model" type="string" required>
  Set to `eleven-english-sts-v2`.
</ParamField>

<ParamField body="file" type="file">
  The audio file, sent as `multipart/form-data`, up to 50 MB. Send `file` or `audio_url`, not both.
</ParamField>

<ParamField body="audio_url" type="string">
  Public `http` or `https` URL of the audio. The gateway downloads it (up to 50 MB). Send `audio_url` or `file`, not both.
</ParamField>

<ParamField body="voice" type="string" required>
  A voice ID or first name from the [voice list](/api-reference/audio-speech#voices), for example `JBFqnCBsd6RMkjVDRZzb` or `George`. Names are case-insensitive.
</ParamField>

<ParamField body="stability" type="number">
  From `0` to `1`. Lower values give a broader emotional range; higher values sound more consistent.
</ParamField>

<ParamField body="similarity_boost" type="number">
  From `0` to `1`. How closely the output follows the original voice.
</ParamField>

<ParamField body="style" type="number">
  From `0` to `1`. Exaggerates the voice's speaking style.
</ParamField>

<ParamField body="use_speaker_boost" type="boolean">
  Boosts similarity to the original speaker.
</ParamField>

<ParamField body="remove_background_noise" type="boolean">
  Removes background noise from the input before changing the voice.
</ParamField>

<ParamField body="seed" type="integer">
  From `0` to `4294967295`. Makes repeated requests more repeatable, without guaranteeing identical audio.
</ParamField>

<ParamField body="response_format" type="string" default="mp3">
  `mp3`, `opus`, `pcm`, or `wav`. See [Output formats](/api-reference/audio-speech#output-formats).
</ParamField>

## Request

Upload a local file as `multipart/form-data`:

```bash theme={null}
curl https://api.snapgen.org/v1/audio/voice-changer \
  -H "Authorization: Bearer $SNAPGEN_API_KEY" \
  -F model=eleven-english-sts-v2 \
  -F file=@performance.mp3 \
  -F voice=EXAVITQu4vr4xnSDxMaL \
  --output changed.mp3
```

Or send JSON with a public `audio_url`:

```bash theme={null}
curl https://api.snapgen.org/v1/audio/voice-changer \
  -H "Authorization: Bearer $SNAPGEN_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "eleven-english-sts-v2",
    "audio_url": "https://example.com/performance.mp3",
    "voice": "EXAVITQu4vr4xnSDxMaL"
  }' \
  --output changed.mp3
```

The response body is the audio file, with a `Content-Type` that matches `response_format`.

## Price examples

| Length | Price |
| - | - |
| 10 seconds | \$0.03 |
| 1 minute | \$0.18 |
| 5 minutes | \$0.90 |

<Note>
  Synchronous audio endpoints reject `Idempotency-Key`. If a request times out, check your Console request logs before you retry.
  See [Voice changer](/api-reference/audio-voice-changer) for every field, the response, and errors.
</Note>