Remove Hum
Reduce steady 50 or 60 Hz electrical hum and its first three harmonics.
Up to 200 MB. Decoded at 48 kHz on this device. Long recordings may exceed the browser memory limit.
Narrow notch filters can also reduce musical notes at those frequencies. This does not remove broadband noise.
How the hum remover works
What it does
Electrical hum sits at the mains frequency of the power supply, 50 Hz in Europe, Africa and most of Asia, and 60 Hz in North America and parts of South America, plus whole-number multiples of it. The tool places four very narrow notch filters on the fundamental and its first three harmonics: 50, 100, 150 and 200 Hz, or 60, 120, 180 and 240 Hz.
Each notch has a Q of 30, so it cuts a band only a few hertz wide and leaves the frequencies around it alone. Both channels get the same filters.
Settings
- Mains frequency: 50 Hz or 60 Hz. Pick the one that matches where the recording was made. If you are unsure, try both and listen.
- Hum reduction: 0 to 100 percent. This blends the filtered signal with the original. At 100 percent you hear only the filtered signal, at 50 percent half of each.
Files and output
- Mono or stereo files up to 200 MB. Files with more than two channels are refused.
- Audio is decoded at 48 kHz on your device, so about 11 minutes of mono or 5.5 minutes of stereo fit in the memory limit.
- The result is a 24-bit WAV at 48 kHz with the same number of channels. If the processed audio would go over full scale, the whole file is turned down by a fixed amount, and that amount is shown.
Good to know
- Hum with harmonics above the fourth (a buzz rather than a hum) is only partly reduced.
- Bass notes that land on the notch frequencies, such as G near 98 Hz or a low B near 61.7 Hz, can lose a little level.
- Hiss, fan noise and room noise are broadband and are not removed.
Preview the result before exporting a WAV.
How it works.
- 1Choose a recordingOpen a mono or stereo audio file. Nothing is uploaded.
- 2Adjust and listenSet the controls, process, and compare with the original. Keep only changes that help your recording.
- 3Save a new WAVDownload a 24-bit WAV with your plan access. Your original file is unchanged.
Questions.
What are the limits?
Narrow notch filters can also reduce musical notes at those frequencies. This does not remove broadband noise.
Does it master my song?
No. This is a focused repair step, not loudness mastering. Only output that would clip is attenuated, and that amount is shown.
Should I choose 50 Hz or 60 Hz?
Use 50 Hz for recordings made in Europe, Africa, most of Asia and Australia, and 60 Hz for North America and parts of South America. If the hum is still there after processing, switch to the other setting and process again.
Why is a buzz still audible?
The tool only cuts the fundamental and its first three harmonics. A buzz has energy far above that, which these filters do not reach.