Remove hum from audio
A low electrical buzz under the voice? fix.fm finds the 50 or 60 Hz hum and removes it without touching the voice. Free, nothing uploaded.
Never uploaded. Everything runs in your browser.
What's happening
Hum is a low, steady buzz under the voice, like a fridge or an old fluorescent light. It comes from mains electricity leaking into the audio: a ground loop between two devices, a cable running past a power lead, or a charger plugged into the same setup as the mic. It sits at exactly 50 Hz in most countries, or 60 Hz in North America and a few others, with a row of higher tones stacked on top.
fix.fm looks for sharp, steady peaks at those frequencies and measures how loud they are next to the voice. Hum 40 dB under the voice is faint, 30 dB under is easy to hear, and at 20 dB under it gets in the way.
How it works here
- 01
Pins down the hum
It finds the exact pitch of the buzz, 50 or 60 Hz, down to a thousandth of a Hz, plus the higher tones stacked on top.
- 02
Cuts just those tones
Very narrow notches, a fraction of a Hz wide, take out the hum and leave the voice around them alone.
- 03
Stays on your computer
Your file is never uploaded. The fix runs in this browser tab.
Questions
What causes hum in audio?
Mains electricity getting into the signal. The usual cause is a ground loop, when two pieces of gear are plugged into different sockets and connected by an audio cable. Unshielded cables running past power leads and phone chargers can do it too.
Is my audio uploaded anywhere?
No. The file is read and fixed inside this browser tab and never sent anywhere.
Does it matter if my hum is 50 Hz or 60 Hz?
No. fix.fm checks for both and finds the one in your file. 50 Hz is used in most of the world, 60 Hz in North America and parts of South America and Asia.
Will it affect a deep voice?
Very little. The notches are so narrow they only catch the steady hum tone. A voice moves around in pitch, so almost all of it passes through.
How do I stop hum next time?
Plug all your audio gear into the same power strip, keep audio cables away from power leads, and try running a laptop on battery. A ground loop isolator fixes most stubborn cases.