Audio Low Pass Filter
Remove high-frequency hiss and harshness above a chosen cutoff.
Fill in the form and press “Apply filter” to see the result here.
How to use it
- 1Choose your file, or drag it onto the upload area.
- 2Set the options. Every setting is a fixed choice, which is what keeps the conversion safe to run.
- 3Press the button. The job is queued and the page shows it move through waiting, processing and ready.
- 4Download the result. Both your upload and the result are deleted once you have it.
About the Audio Low Pass Filter
Everything above the cutoff is attenuated. A cutoff around 8 kHz reduces tape hiss and sibilance; below about 4 kHz the result starts to sound like a telephone.
A filter cannot separate hiss from wanted detail at the same frequency. It reduces both, so use the highest cutoff that fixes the problem.
Questions people ask
What actually does the work?
FFmpeg, the same open-source toolchain most video software is built on. It runs as a separate process with a fixed argument list, a time limit and no network access. Nothing from your filename or your settings is ever passed to a shell.
Why does this one take longer than the other tools?
Media work is genuinely expensive: a re-encode reads and writes every frame. The job is queued so that a busy moment slows things down rather than taking the site out, and the page shows where your job is in that queue.
What happens to the file I upload?
It is stored under a random name that is not guessable, processed by an isolated worker, and deleted as soon as you download the result - and in any case automatically after 60 minutes. Uploads are never indexed, shared or used for anything besides producing your result.
Is it free, and do I need an account?
Yes, it is free, and there is no account, no sign-up and no watermark on the result. The project is funded by optional donations.