5 min read
OBS Studio is free recording and streaming software, and its audio filters can turn a noisy room into a clean recording. The filters remove hum, cut background noise, and even out the volume, all while you record. No extra software is needed.
This guide walks through the filters that matter, in the order to apply them. It covers what each filter does, where to set it, and the mistakes that make audio sound worse instead of better.
Set Levels Before Any Filter
Filters cannot fix a clipped recording, so set the level first. Speak at your normal volume and watch the OBS audio meter. The peaks should reach the yellow zone, not the red zone. A level that clips is damaged forever, while a slightly quiet level is easy to raise.
Set the microphone gain on the interface or in the system settings before you touch OBS. The OBS volume slider should sit near the top for a healthy signal, not at the bottom. If the slider sits low, raise the gain at the source instead.
Record a ten-second test and listen back on headphones. The test shows hiss, echo, and hum that the live meter hides. A test clip costs ten seconds and saves an hour of recording that cannot be fixed.
Keep the room as quiet as you can before you filter. Close the door, move the microphone away from the computer fan, and silence the phone. A filter removes a little noise well, but no filter removes a lot of noise without damaging the voice.
Noise Suppression for Background Hiss
Noise suppression removes steady background noise, such as fan hum and room hiss. OBS offers two methods, and the newer neural method sounds better on voices while the older method uses less CPU. Try the newer method first on a modern computer.
Apply noise suppression to the microphone source, not to the whole mix. A filter on the mix can distort game audio and music, while a filter on the microphone touches only your voice. Right-click the microphone source to add the filter.
Set the suppression strength to the lowest value that removes the noise. Too much suppression makes the voice sound watery and robotic, with words that fade in and out. A light touch that leaves a faint hiss sounds more natural than a heavy touch that distorts the voice.
Test suppression with a real sentence, not with silence. Silence tests hide the distortion that appears when you speak. Record a sentence with pauses, and listen for words that cut off or sound thin at the start and end.
Noise Gate for Silence Between Words
A noise gate mutes the microphone when the sound falls below a threshold. Between sentences, the gate closes and the background noise vanishes. When you speak, the gate opens and your voice passes through.
Set the close threshold just above the room noise level, and the open threshold a little higher. A gate that flutters is more distracting than no gate at all.
Set the attack and release times to smooth values. A fast attack cuts the start of a word, while a fast release cuts the tail. An attack of a few milliseconds and a release of a few hundred milliseconds sounds natural for speech.
A noise gate cannot remove noise that is louder than your voice. If the keyboard clatter or the fan is as loud as your speech, the gate opens for the noise too.
Compressor for Even Volume
A compressor evens out the volume by turning down loud peaks and letting quiet parts stay. It keeps a loud laugh from clipping and a quiet aside from vanishing. The result is a recording that is easy to listen to at one volume.
Set the ratio to a gentle value for speech, such as three to one. A high ratio squashes the voice and makes it sound flat. A gentle ratio tames the peaks without killing the natural rise and fall of speech.
Set the threshold so the compressor works only on the loud parts. If the compressor works all the time, the voice sounds squeezed. The gain reduction meter should move on loud words and rest on normal speech.
Add a small makeup gain after the compressor to bring the overall level back up. The compressor turns loud parts down, so the recording gets quieter overall. Makeup gain restores the level without bringing back the peaks.
Limiter, EQ, and the Final Chain
A limiter is the last guard against clipping. Set it just below the clipping point, so any peak that escapes the compressor is caught. A limiter should rarely act, and if it acts often, the earlier stages need fixing.
A gentle EQ can remove low rumble. A small cut below 80 Hz cleans the recording without changing the voice.
Order the filters as follows: noise suppression, noise gate, compressor, EQ, limiter. Each filter works on the output of the one before it, so the order matters. A gate before suppression can chop the noise in a way that confuses the suppressor.
Save the filter chain as a preset once it sounds right. A saved chain applies the same settings to every recording, which keeps your audio consistent. Re-check the chain when you change the microphone, the room, or the interface, because the settings follow the setup, not the software.
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