How to remove background noise from video on a Mac

What kind of background noise do you have?

Listen to a few seconds where nobody speaks, then match what you hear:

The cheapest fix is always the first column. Every clean-up takes something from the voice with the noise, so the less noise you record, the less the voice pays.

Can I remove background noise in iMovie?

Yes. In iMovie on a Mac, select the clips in the timeline, click the Noise Reduction and Equalizer button in the adjustments bar, tick Reduce background noise and drag the slider, which runs from 0% to 100% of the original sound. Apple suggests playing the clip back and adjusting from there. The same controls have an Equalizer menu to lift the voice or boost bass or treble. It is one slider for the whole clip, which suits a light, steady hiss better than a noisy room.

How can I remove background noise from a video for free?

Use what came with your Mac or a free editor: iMovie's slider, or Audacity's Noise Reduction, which learns the noise from a stretch with no speech and then takes that profile out. Audacity's own manual advises the lowest settings that work, because higher values damage the sound you keep, and its Residue option lets you hear what is being removed. Either way, export the cleaned sound and listen on headphones for the watery, underwater sound of a clean-up pushed too far.

How do I remove background noise but keep the voice?

Use a clean-up that separates the voice from the noise, and whatever background noise remover you use, check the words afterwards, not just the noise. A gate or an EQ cuts everything at a level or a frequency, voice included; a voice clean-up model keeps what is voice. But pushed hard, any of them can swallow a quiet last word.

Sharpy's voice clean-up is built around that risk. It tries several strengths, checks each result's words against the original recording and accepts a setting only if it keeps them. If every strength loses words, it writes nothing rather than hand back a damaged track; if you name a preset yourself, it is applied as asked and you are told how many words it cost. On recordings by Sharpy's maker, the settings chosen kept between 97.2% and 98.5% of his words.

The clean-up panel opens on two presets. Open the fold and there are seven settings:

1. How much of the room to take out.
2. The high pass under the rumble.
3. The cut that takes the box out of a small room.
4. The presence lift, for consonants rather than brightness.
5. The compressor's threshold.
6. Its ratio.
7. The limiter's ceiling.

The edit records all seven, so "why does this clip sound different?" is answered with numbers. The default clean-up runs at eight to ten times real time on the base Mac mini M4, and memory stays flat on long recordings: 121 MB for 32.7 minutes of sound.

How do you remove echo from a video?

Stop it at the source where you can, then take the room down with a clean-up, at a strength that still sounds natural. By the time it reaches the microphone, a long echo is mixed into every word, so no tool removes it completely. The blanket in the picture above does more than any slider.

In Sharpy, the first clean-up setting is how much of the room to take out, and the third takes the boxy sound of a small room out of the voice. When you re-record a line in a drier place, Sharpy works the other way: it measures how long the original room rings after each word and gives the new take the same room, so the line does not sound pasted in. A known 0.45-second room read 0.37, and the fitted line's tail matched the original within half a decibel.

What else does Sharpy fix in a noisy clip?

• Hum and clicks. Each clip carries a sound chain, and you can ask Sharpy to find the hum and the clicks instead of typing frequencies. In one test it found no hum and two plosives, and repaired both.
• EQ and dynamics. The chain also takes EQ bands, a compressor, a gate and a de-esser, given in plain units: an 80 Hz high-pass with a +6 dB lift at 3 kHz measured within 0.24 dB of its design at every third-octave from 125 Hz to 8 kHz.
• Room tone under every gap. A cut leaves a hole in the background. Sharpy fills it with the room itself, lifted from the recording's quietest stretches and never repeated within 20 seconds, so a cleaned voice never drops into digital silence between sentences.
• How far the voice sits above the room. Sharpy measures it, for example speech at −17.4 dBFS over a −25.8 dBFS floor, 8 dB apart, so you know before you start how much there is to gain.

All of it runs on your Mac, with no upload and no limit on hours. Once the voice is clean, audio mixing for video sets it against music and effects, and removing filler words and dead air tightens the delivery.

Sources

Checked on 18 October 2026.

• Apple: correct and enhance audio in iMovie on Mac
• Audacity manual: Noise Reduction