# Remove static, hiss, and hum from audio

Clear the buzz and hiss from behind a voice, keeping the voice as recorded.

## Where static comes from

Hiss is a steady, high shhh. It comes from microphones and their preamps, and grows when the gain is turned up to lift a quiet voice; cheap mics and old cassettes hiss too. Hum is a low tone at the power grid's frequency: 60 times a second in the US and Canada, 50 in the UK and most of Europe. It comes from cables near power lines, ground loops between connected gear, and some lights. Buzz is a harsher hum, often from light dimmers and fluorescent lights.

Next time, get closer to the mic and turn the gain down, keep audio cables away from power cables, and plug connected gear into the same outlet.

Tool: Remove noise (`remove_noise`). The same tool's other pages: https://audo.ai/noise-removal.md, https://audo.ai/remove-noise-from-video.md. Price: 3 credits a minute of input for whole files, charged only when a job succeeds.

## Free API

```bash
curl -F file=@old-interview.wav https://audo.ai/api/try/remove-noise -D response.headers -o response.body
```

Read response.headers and response.body before naming media. Handle 202, 200 JSON and errors with the complete response client at https://audo.ai/docs/api#responses.

Free for the first minute 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"`), omitting free runs the whole file with credits if the balance covers it, otherwise the free portion if quota remains. Set free=true to prohibit spending; for paid whole files use free=false with an approved positive max_credits. Details: https://audo.ai/docs/api.md

## Options

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

- `noise_reduction`: How much of the noise to turn down, as a percentage. 100 turns down all it can; lower values keep some of the background. Default 100.
- `auto_volume`: Sets the whole file to -16 LUFS with one gain, and limits peaks to -1 dBTP. It doesn't balance loud and quiet speakers. Default true.
- `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 `remove_noise`:

> Turns down background noise, hiss, hum, and room noise behind speech, keeping the speaker's real voice: it filters the recording and adds no sound of its own. Then sets the file to -16 LUFS. Made for voices: music and other sounds are turned down too. Works on video. Use it when the voice is fine but there's noise behind it. Not for echo, phone, or damaged audio (enhance_voice). Set free to true to do the first minute at no cost, up to 3 times a day; otherwise it costs 3 credits a minute, charged only if the job succeeds. Returns job_id; then call get_job.

Example: "Use Audo to remove the hiss and hum from old-interview.wav."

## More

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