Remove static from audio: hiss, hum and crackle

Last updated: November 3, 2026

Choose a file

or drop audio or video here

MP3, WAV, M4A, FLAC, OGG, MP4, MOV, WebM · up to 60 minutes

Upload the recording above and play the free preview. In our tests, Enhanced removed tape hiss far better, both modes removed ground-loop hum, and Standard removed more cable crackle. Standard runs in your browser and is free for files up to 5 minutes, so start there unless your static is a steady hiss.

Which kind of static do you have?

“Static” covers three different sounds with different causes. Listen to a quiet moment between words and match it below.

Three kinds of static, what usually causes them, and which mode did better in our test
What you hear	Usual cause	Better in our test
Steady “shhh” hiss	Input gain set too high, a cheap preamp, old tape	Enhanced
Low “mmm” or “bzzz” hum	Ground loop, a charger or power supply, an unbalanced cable near power	Both, Enhanced slightly quieter
Pops, clicks and crackle	A loose or broken cable, a dirty jack	Standard

Hiss: Enhanced removes far more

Hiss covers the same high frequencies as s and t sounds, which makes it hard for a small model. In the pauses between words, Standard lowered the hiss from −23 dB to −52 dB, a 29 dB drop. Enhanced took it to −93 dB, which is digital silence, and the voice stayed as bright as the clean recording.

If your recording has hiss, use the Enhanced preview on your own file before cleaning the whole thing.

Sample: a narrator with tape hiss mixed in (Freesound #443339, CC0).

Electrical hum: both modes remove it

Ground-loop hum is a steady tone at 50 or 60 Hz and its harmonics, well below most of the voice. Both modes removed it: the pauses dropped from −23 dB to −69 dB with Standard and −82 dB with Enhanced. Standard left the voice’s high frequencies unchanged; Enhanced made it slightly brighter than the clean recording.

Standard is enough for most hum, and it is free for files up to 5 minutes.

Sample: a narrator with ground-loop hum mixed in (Freesound #454037, CC0).

Crackle from a bad cable: Standard removed more

Crackle is short bursts rather than a steady sound. Here Standard did better: the loudest crackles in the pauses fell from −9.5 dB to −36 dB, against −29 dB with Enhanced, and the background between them was quieter too. The trade-off is that Standard took a little brightness out of the voice (2.6 dB less energy above 4 kHz than the clean recording), while Enhanced kept it.

Crackle that lands on top of a word is harder to remove than crackle in a pause. If a cable is crackling, replacing it will help more than any software.

Sample: a narrator with crackle from a broken cable mixed in (Freesound #568818, CC0).

Full results

Each sample is 12 seconds of a narrator from a public-domain LibriVox recording, mixed with a real static recording released under CC0 on Freesound. The static was set about 6 LU quieter than the speech, which is louder than in most recordings. Both modes got the same file, and the outputs are time-aligned with it. We measured the pauses between words (10-millisecond slices where the clean voice is at least 40 dB below its loudest point) and, in the louder half of the speech, how much energy sits above 4 kHz, where consonants live. See how we test for the rules we follow.

Measurements on each 12-second sample, tested 3 November 2026 (dB; lower is better for noise, closer to the clean voice is better for energy above 4 kHz)
Static	Version	Noise in pauses	Loudest noise in pauses	Voice energy above 4 kHz
Tape hiss	Clean voice	—	—	−18.6
Tape hiss	Original	−23.4	−14.3	−17.0
Tape hiss	Standard	−52.3	−29.8	−19.0
Tape hiss	Enhanced	−93.2	−42.3	−15.2
Ground hum	Clean voice	—	—	−32.4
Ground hum	Original	−22.8	−17.8	−33.6
Ground hum	Standard	−69.2	−48.6	−33.0
Ground hum	Enhanced	−82.0	−40.3	−28.4
Cable crackle	Clean voice	—	—	−28.5
Cable crackle	Original	−37.5	−9.5	−22.9
Cable crackle	Standard	−72.6	−35.7	−31.1
Cable crackle	Enhanced	−63.4	−28.6	−26.5

Stop static before you record

Hiss usually means the input gain is too high on a quiet microphone. Move the mic closer and turn the gain down, rather than boosting a weak signal.

Hum often comes from a ground loop: two devices plugged into different outlets, or a laptop charging while it records. Run the laptop on battery, plug everything into one power strip, and keep audio cables away from power cables.

Crackle that changes when you touch a cable means the cable or the jack is failing. Swap the cable before the next session.

What this test doesn’t show

This is a small test: three 12-second samples, one narrator each, with static mixed in rather than recorded together with the voice. The Freesound files are compressed previews, and static in a real recording may sit lower or change over time. We measured noise and brightness, not overall quality, and used Standard at its strongest setting. We did not test buzz from a phone near the mic, digital clicks from dropped samples, or distortion from a clipped input, which noise removal can’t undo.

Hear the difference in 30 seconds