One part of a recording is too quiet, or has noise: how to fix it

You play back a meeting recording andthe first few seconds are a chair being dragged. Orone person is too quiet to make out, and only their turns. You do not want to change the whole recording — just that part.

AudioMass does exactly that, for free. No install, no account: open it in a browser, drag across the part you want to change, pick something from a menu.We used it and measured it — the network traffic and the processing time (checked 2026-09-25).

1. When you need this

• A thump or a cough in the first and last few seconds
• One participant is quiet, and only their turns are unintelligible
• Someone knocked the microphone, once, halfway through
• Two minutes of small talk in the middle that you want gone

2. What AudioMass is

• Free, with no account.
• Written by Pantelis Kalogiros. The source is public, and the project's own code is MIT-licensed (bundled third-party libraries keep their own licences).
• Processing happens inside your browser. Your audio is not sent anywhere — we check that in section 4.
• It covers a lot of ground: 19 effects, including gain, fades, noise reduction, EQ, compressor, reverb, reverse and silence removal.

3. How to use it (4 steps)

1. Open audiomass.co. A welcome panel appears first — press Esc or click outside it to dismiss it.
2. File → Load from Computer, or drag a file onto the window. A waveform means it loaded.
3. Drag across the waveform to select the stretch you want to change. The length of the selection appears as Duration at the top right. Shift + A selects everything.
4. Pick something from Effects — Gain for volume, Fade Out to taper the end, Noise Reduction (Voice) for background noise. Then File → Export to save.

Shortcuts here use Shift, not Ctrl: Shift+Z to undo, Shift+C to copy, Shift+X to cut. Worth knowing before you conclude that undo is missing.

4. Checking that nothing is sent

"Runs in your browser" is a claim, not a fact, until you look. We loaded a 28.5-second recording, applied noise reduction and exported it, logging every request.

• Opening the page made 5 requests, all to audiomass.co itself, all for the page
• Between loading the file and exporting it, there wereno POST or PUT requests at all — nothing was sent outward

You can check it yourself without any tools: open the page, then disconnect from the internet. Loading, editing and saving all still work.

5. The numbers we measured

A 28.5-second, 48kHz, mono meeting recording, in Chrome on a desktop, on 2026-09-25.

We measured the noise reduction too. On a recording with air-conditioning noise mixed in, thespeech-quality figure improved by 4.2 dB. There are no settings to adjust: you select and click. It is built for speed rather than control.

6. Where people trip up

• WAV export is 44.1kHz. The export panel says so — "wav (44100hz)". A 48kHz file comes back at 44.1kHz, which can matter when you are matching audio to video.
• Undo is Shift+Z. Ctrl+Z does nothing, which reads as "there is no undo".
• Long recordings get heavy. The whole waveform is held at once, so it is not built for multi-hour files.
• Close the tab and your work is gone. That is the flip side of running purely in the browser. File → Save Draft Locally keeps a draft on your own machine; use it for long sessions.

7. When it fits, and when it does not

It fits

• Fixing one part of a recording
• Editing something you would rather not hand to a stranger, without installing anything
• A work computer where you cannot install software
• A one-off job that does not justify finding and learning an application

It does not

• Multi-hour recordings
• Layering several sources into a piece of music — the multitrack feature is still in beta
• Applying one change to a whole file. There are quicker ways to do that

8. If you want to fix the whole file

AudioMass for one part; our own tools when the whole file needs the same treatment. There is nothing to select, so it is open, drop, press.

• Remove background noise → Remove noise
• Even out the volume → Fix the volume
• Cut the head and tail → Trim audio
• Change the format → Convert audio
• Pull audio out of a video → Extract audio

Questions