Low Pass Filter — Cut High Frequencies in Audio, Online Free
Sweep the cutoff from 20 kHz down to 300 Hz and keep only the frequencies you want.
Drop an audio file, or click to browse
MP3, WAV, M4A, OGG, FLAC, and more
Processed locally — your file never leaves this tab
00:00.00 / 00:00.00
Adjust — fades, volume, speed, reverse
Precise times
A low-pass filter keeps the low end and rolls off everything above the cutoff — the honest way to remove hiss, sharp sibilance, squeaks and harsh digital edge. Unlike a noise remover, it never guesses what is noise: everything above your cutoff simply goes. Drop a file, sweep the cutoff down until the annoyance disappears, export. Everything runs in your browser: the file is never uploaded.
When to low-pass audio
- Remove constant hiss and air conditioning whine from voice recordings.
- Soften harsh, spitty cymbals or sibilance in a rough mix.
- Make audio sound muffled on purpose — behind a wall, phone-voice, lo-fi or meme.
How to use the Low Pass Filter
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Drop your audio
Any MP3, WAV, M4A, OGG or FLAC file. Processing stays on your device.
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Lower the cutoff
Sweep from 20 kHz down until the noise disappears — 8–12 kHz is a common resting point for voice.
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Preview and export
Check that voices still sound natural, then export as MP3 or lossless WAV.
Everything above the cutoff goes
A low-pass filter rolls off what is above the cutoff. It is not a noise remover. It does not separate hiss from the signal. It turns down every frequency past the point you set, including consonants and cymbals if you set it too low.
There is no resampling and no pitch change. The export still encodes once: MP3, or WAV if you want the filtered audio without another lossy generation.
Cutoffs that match the job
The number is a starting point. Listen, because the same cutoff muffles one file and only softens another:
- Voice: try 8–12 kHz first. Below about 5 kHz speech sounds muffled. Below 2 kHz it sounds like a telephone.
- A soft lo-fi music effect: 4–8 kHz.
- Sharp cymbals you only want tamed: 12–16 kHz. Below 3 kHz music sounds distinctly dull.
The high-pass is the other direction
The high-pass filter removes rumble and low-end boom below its cutoff. This page removes hiss and harshness above its cutoff. Using both leaves a band in the middle.
A few decibels of treble, rather than removing the top outright, is the treble booster or the equalizer. Those shelves do not sweep a hard cutoff.
Low Pass Filter FAQ
Is my audio uploaded?
No. The filter is a Web Audio low-pass biquad inside your browser tab — there is no upload step. You can go offline after the page loads and the tool keeps working.
Is a low-pass filter the same as noise removal?
No — and that is its strength. A noise remover separates noise from signal intelligently; a low pass blindly cuts everything above the cutoff. For constant, wideband hiss it is more reliable than any algorithm.
Why do voices sound muffled at low cutoffs?
Consonant clarity lives between 3 and 8 kHz. Below about 5 kHz speech starts to sound muffled; below 2 kHz it sounds like a telephone. For voice, try 8–12 kHz first.
How is this different from the high-pass filter?
Opposite directions: the high pass removes rumble, hum and low-end boom below your cutoff; the low pass removes hiss and harshness above it. Using both leaves only a chosen band.
What cutoff should I use for music?
For a soft lo-fi effect try 4–8 kHz. To clean sharp cymbals, 12–16 kHz usually suffices. Below 3 kHz music sounds distinctly muffled — trust your ears over numbers.
Does it work on a phone?
Yes. The editor is built for touch — drag to select, sweep the cutoff, export. Works in current Chrome, Edge, Firefox and Safari, on desktop and mobile.
Related tools
High Pass Filter
Sweep the cutoff from 20 Hz up to 5 kHz and strip everything below it.
Open High Pass Filter
Audio Equalizer
Low, mid and high shelves with ±15 dB per band — the honest three-knob EQ.
Voice Recorder
Record your microphone, trim the take, save it as MP3 — nothing leaves your device.