# Volume booster: make audio louder

Make quiet recordings louder, at the right level for where they're going.

Tool: Set loudness (`adjust_loudness`). Price: 1 credit a minute of input for whole files, charged only when a job succeeds.

## Free API

```bash
curl -F file=@episode.wav -F target=podcast https://audo.ai/api/try/loudness -o episode-loud.wav
```

Free for the first 3 minutes of each file, 3 times a day per person, with no key or account. Uploads up to 100 MB, 2 at once from one address. The response is the result itself; a job that runs longer than about 30 seconds returns 202 with a link to check on it. With an API key (`-H "Authorization: Bearer $AUDO_API_KEY"`), the same request processes the whole file with credits. Details: https://audo.ai/docs/api.md

## Options

Form fields with the same names as the MCP tool's inputs:

- `target`: Where it's going: podcast (-16 LUFS), streaming (-14 LUFS), broadcast (-23 LUFS), audiobook (ACX checks), or custom (set custom_lufs). Default podcast.
- `custom_lufs`: The loudness for target custom, in LUFS (-30 to -5), such as -18.
- `output_format`: The result's format: same (as the input; a video stays a video), wav, mp3, m4a, or flac. Default same.

## Languages

Any language: it works on the sound, not the words.

## From an assistant (MCP)

Add https://audo.ai/mcp and sign in (setup for each assistant: https://audo.ai/setup.md). The tool is `adjust_loudness`:

> Sets how loud a recording is for where it's going, with peaks limited. Use it before publishing, as the last step: it can save as MP3 or another format, so earlier steps stay lossless. Not for removing noise (remove_noise). Set free to true to do the first 3 minutes at no cost, up to 3 times a day; otherwise it costs 1 credit a minute. Returns job_id; the result has loudness before and after.

Example: "Use Audo to set episode.wav to podcast loudness, −16 LUFS."

## More

- Every tool: https://audo.ai/llms.txt
- OpenAPI: https://audo.ai/api/openapi.json
- This page for people: https://audo.ai/volume-booster