Built for streamers, quietly the best free tool for capturing a video call, a stream, or anything else your computer is playing.
OBS Studio is video software, and we are recommending it on an audio site. The reason is simple: browsers and ordinary recorders capture microphones, not the sound your computer is producing. If you need to record a Zoom call, a webinar, a streamed lecture, a YouTube video or game audio, you need something that can tap the system output, and OBS does it for free on Windows, macOS and Linux while everything else in that category charges.
OBS treats audio sources the way a mixing desk does. The mixer panel at the bottom of the window lists everything it can hear: Desktop Audio (what your speakers are playing), Mic/Auxiliary Audio (your microphone), and any extra source you add. Each gets its own fader, its own meter, and its own filter chain.
The important setting is buried in Settings → Output → Recording, in advanced mode: Audio Track checkboxes. Assign the microphone to track 1 and desktop audio to track 2 and OBS writes both into one file as separate tracks. Afterwards you can mute the guest, boost your own voice, or extract each side independently. That capability alone is worth the setup time, and it is exactly what people buy commercial call recorders for.
Right-click any source, choose Filters, and you get a genuinely useful processing chain that runs live while recording:
Because these are applied on the way in, the recording arrives already usable. That is the opposite of the usual workflow and it saves a real amount of editing time for anything conversational.
You can use OBS as a pure audio recorder: add no video sources, set the recording format to a container that suits you, and record. Most people leave it in MKV because MKV survives a crash where MP4 does not, then use OBS's own Remux Recordings tool afterwards. Extracting a WAV or MP3 from the result is a one-line job for ffmpeg, or you can open the file directly in Audacity.
It also writes to disk continuously, encodes with hardware acceleration where available, and happily runs for hours. For long unattended captures it is more dependable than anything running in a browser tab.
OBS is configured, not just opened. Scenes, sources, output modes, encoders, tracks, bitrates: the first session involves reading. The defaults are sensible for streaming and not always for recording, and the audio-track assignment that makes it so useful is hidden behind Advanced output mode.
It is also not an editor. There is no waveform, no trimming, no fades. OBS captures; something else finishes the job. And the desktop-audio capture on macOS remains more fragile than on Windows, varying with the system version.
Not the program to reach for when you want to record your voice, but the moment the sound is coming out of your computer rather than into your microphone, OBS is the free answer and there is not a close second. Set it up once, save the scene, and it takes ten seconds every time after that.