Remove electrical hum
Notch out 50/60 Hz electrical hum and its harmonics without dulling the rest.
Runs locally in your browser. Enable JavaScript to use the interactive tool. The practical details remain available below.
What Remove electrical hum actually does
Mains hum sits at one frequency and its multiples, which makes it the one noise problem with an exact answer: notch the fundamental and the harmonics and leave everything else alone. The difficulty is that a notch deep enough to kill the hum can also hollow out the low end of a voice, and a downloaded file is a slow way to discover that. This page keeps the source and the result on one transport so the trade is audible in the same screen where the frequency and the harmonic count are chosen.
How to use it
- Choose an audio file. The waveform is drawn locally.
- Pick the mains frequency for the region the recording was made in, 50 Hz or 60 Hz.
- Choose how many harmonics to notch and how deep the notches go.
- Run, then switch the player between source and result to hear what the notches took with them.
Useful for
- Cleaning a buzz picked up from unbalanced cabling or a ground loop.
- Rescuing an interview recorded next to a fluorescent light or a dimmer.
- Removing hum from a digitised tape without touching the rest of the spectrum.
Limits worth knowing
- Only hum at the mains fundamental and its harmonics is addressed. Broadband hiss needs the noise reducer instead.
- Deep notches on the fundamental remove real low-frequency content along with the hum, which is why the comparison is on the page.
- Hum that drifts in frequency is only partly caught by fixed notches.
Questions people ask
Is the file uploaded?
No. Everything runs in this tab.
Which frequency should I choose?
It follows the electricity supply where the recording was made, not where it is being edited.
Why is there still a low rumble?
Rumble is not hum. It is broadband low-frequency energy and is not at a single frequency, so notches do not remove it.