Cut everything below (high-pass) or above (low-pass) a cutoff frequency using real Butterworth-style biquad filters — the standard fix for rumble, mic-stand thump, or harsh hiss.
The Audio Filter removes unwanted parts of the frequency spectrum: rumble and wind with a high-pass, hiss with a low-pass, a narrow band for telephone-style sound, or mains hum (50/60 Hz and harmonics) with a notch filter.
Filters are true Butterworth designs — the flattest possible passband, −3 dB exactly at the cutoff — with selectable slopes from 12 to 48 dB per octave.
Higher-order Butterworth filters are built by cascading biquad sections whose Q values are fixed by the order: 0.7071 for order 2; 0.5412 and 1.3066 for order 4; 0.5176, 0.7071 and 1.9319 for order 6. Each pair adds 12 dB/octave. The hum remover places narrow notches (Q 30) at 50 or 60 Hz and optionally its 2nd–4th harmonics, since mains hum is rich in harmonics.
The live preview and the exported file use identical filter chains.
High-pass at 80–120 Hz.
Notch at 50/60 Hz plus harmonics.
Low-pass at 10–14 kHz.
Band-pass 300 Hz–3.4 kHz.
| Types | High-pass, low-pass, band-pass, notch hum remover |
|---|---|
| Slopes | 12, 24, 36, 48 dB/octave |
| Design | Butterworth cascade |
A filter with maximally flat response in the passband and −3 dB at the cutoff.
How quickly the signal is reduced per doubling of frequency beyond the cutoff.
How sharply the filter cuts past the cutoff: 12 dB/octave is gentle, 24 is the usual studio default, 36 is very steep. Steeper filters remove unwanted frequencies more completely but can sound more 'processed' near the cutoff.
A high-pass at roughly 80–120Hz clears rumble without thinning most voices. Go higher only if the voice is naturally light or the rumble is severe.
This tool runs entirely in your browser using the Web Audio API. Nothing is uploaded, stored or shared — there is no server to send your file to, so it works offline once the page has loaded.
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