Remove Hum (50/60 Hz)
Mains hum sits at 50 or 60 Hz plus whole-number multiples. Notch filters take it out while leaving the rest of the sound alone.
MP3, WAV, M4A, FLAC, OGG, Opus, AIFF, WMA, AMR and the sound of most videos. Files stay on your device.
How it works
- Choose an audio file.
- Choose 50 Hz or 60 Hz and how many harmonics to remove.
- Preview and widen or narrow the notches as needed.
- Export and download.
How hum removal works
Mains hum is a steady tone at 50 Hz (Europe, Asia, Africa) or 60 Hz (North and South America and parts of Asia), plus tones at whole-number multiples of it, called harmonics. This tool puts a very narrow notch filter on the hum frequency and on as many harmonics as you choose, so those frequencies are removed and the rest of the sound is left alone.
Auto mode checks which of 50 and 60 Hz fits the spectrum of the first five minutes of your file better and uses that frequency. The page tells you whether it found hum and how strong it is. If it finds none, choose the frequency yourself; some faults make the hum at double the mains frequency (100 or 120 Hz), which you can enter under Other.
Width and harmonics
Notch width is given as Q: a higher Q is narrower. At Q 30 a notch at 60 Hz is only about 2 Hz wide, so voices and music are almost untouched, but the hum has to sit exactly on the frequency. If a trace of the hum remains or it wanders, lower the Q to widen the notches. The plot shows the filter curve. Harmonics above 45 percent of the sample rate are skipped automatically.
Limits
Notches remove hum that is a steady tone. A buzz with many harmonics, a crackle, or hum that changes pitch needs more notches or a wider Q, and some bass notes at 50 or 60 Hz (or their multiples) will lose a little energy too. For hiss and other broad noise use Noise reduction.
Questions
How do I know if it is 50 Hz or 60 Hz hum?
Leave it on Auto: the page measures the file and tells you. It depends on the electricity supply where the recording was made, not where you are now.
The hum is still there after processing. What now?
Add more harmonics (up to 20), lower the Q so the notches are wider, or check whether the hum is at 100 or 120 Hz and enter that under Other.
Will it damage the bass?
The notches are narrow, so only a thin slice around each hum frequency is affected. Bass notes that sit exactly on 50, 60 or their multiples lose some level; widen the notches less if that matters.
Is this the same as a ground-loop fix?
It cleans the recording after the fact. The fix at the source is a ground-loop isolator or a different cable or outlet, which gives a cleaner recording to begin with.
Is my audio uploaded?
No. Everything runs in your browser and the file never leaves your device.