Remove Background Noise From Audio

Remove hiss, fan noise and background noise from a recording

Steady background noise easily ruins a recording: hiss from a cheap mic, a computer fan, air conditioning, a fridge, an engine, rain, the hum of a room. The tool analyzes the quietest moments of the file (the pauses between sentences, the start before you speak) to measure that noise, frequency by frequency, then reduces it everywhere, including while you speak, letting through whatever stands clearly above the noise, meaning the voice. This is spectral noise reduction, the same family as Audacity's "Noise Reduction" effect, without having to select a noise sample by hand. It works on voice as well as music. It's most effective on continuous noise; sudden, irregular sounds (a car horn, people talking nearby, a slamming door) are much harder to remove and stay partly audible.

Light, medium or strong: choosing the right strength

The more noise you remove, the more you risk damaging the voice: push it too far and it can sound slightly metallic or "underwater", with little warbling artifacts in the background. The light setting reduces noise by about 10 dB and leaves the voice untouched: perfect for a little hiss. The medium setting, the default, removes about 20 dB, which makes most fans and air conditioners almost inaudible. The strong setting goes up to nearly 30 dB for very noisy recordings, at the cost of a slightly less natural voice. The easiest way is to try: start the cleanup, listen while switching between "Before" and "After" on the same passage, then change the strength and run it again; you don't need to re-add the file. Tip: a few seconds of silence at the start of a recording give a more reliable noise measurement.

Remove 60 Hz or 50 Hz electrical hum

Hum, that low, steady buzz, almost always comes from the power supply: a poorly shielded cable, a guitar plugged into an amp, a ground loop between two devices, fluorescent lights or a dimmer. It has a precise frequency, that of the mains: 60 Hz in the United States, Canada, Mexico and part of South America, 50 Hz in the UK, Europe, Australia, Africa and most of Asia, with harmonics at 120, 180, 240 Hz (or 100, 150, 200 Hz). When you check "Reduce electrical hum", the tool detects which of the two is present, then cuts the fundamental and its first five harmonics with very narrow filters that remove almost nothing else. If it doesn't find a clear one, it applies both sets as a precaution. The rest of the background noise is then reduced according to the strength you chose.

Remove noise from a video without re-encoding it

For a video shot on a phone in the wind, in a car or near a road, only the soundtrack needs cleaning. The tool extracts the sound, removes the noise, then puts it back into the video while copying the picture as is: no quality loss, and a fast save, even for a 4K video. The result is an MP4 that plays on every phone and computer, ready to post on YouTube, TikTok or Instagram. Everything happens in your browser with FFmpeg and a noise reduction filter computed on your device: the video isn't sent to anyone. If the sound is still too quiet after cleanup, boost it with "Increase Video Volume"; to record your voice directly, use the "Online Voice Recorder".