Open the editor
Before the editor

How to record a reaction video
with OBS, a clean voice and no echo

Record two separate files: the video you react to, and yourself on a webcam and microphone while you watch it on headphones. In OBS that is one scene with your camera and your microphone, the computer’s sound muted, recorded as MKV. Both files then go straight into the editor.

Open the editor, free The whole process
  • Headphonesthe video stays out of your voice
  • Desktop Audio mutedthe recording carries you and nothing else
  • MKVsurvives a crash, opens directly in the editor
The kit

What you need

Nothing here costs money except the microphone, and a laptop one is fine to start.

The video, as a file

The original file is sharper than any screen recording and smaller too. Where to get it, and what the copyright rules mean for it.

A webcam

The one built into a laptop works. Light matters more than the camera: a cheap webcam in good light beats an expensive one in the dark.

A microphone

Any USB microphone sounds better than a laptop’s. The automatic cut listens to it, so a clear voice is worth more than a sharp picture.

Headphones

Not optional. Through speakers the microphone records the video too: an echo you cannot remove, and cuts that fire on the video instead of on you.

OBS Studio

Free, for Windows, macOS and Linux, from obsproject.com. Any other recorder that saves a video file works too.

A light in front of you

A window or a lamp behind the screen, facing you. A light behind you turns your face into a silhouette.

Set up once

One scene in OBS

The recording should carry your picture and your voice, and nothing else.

  1. 1
    Your cameraSources → + → Video Capture Device, pick your webcam. In its properties choose 1920x1080 if the camera offers it.
  2. 2
    Your microphoneSources → + → Audio Input Capture, pick your microphone.
  3. 3
    Mute the computerIn the Audio Mixer, mute Desktop Audio. The video’s sound already lives in its own file; recording it again only puts it under your voice.
  4. 4
    Picture settingsSettings → Video: set the base and output resolution to your camera’s, and 30 frames per second.
  5. 5
    Recording formatSettings → Output → Recording: MKV, and note the recording path so you can find the file later.
What the cut listens to

Audio the automatic cut can read

The editor finds where you talk from how loud your microphone is. A voice that stands clearly above the room gives clean cuts; here is how it decides.

Level

Talk the way you will during the reaction. Your voice should peak in the yellow part of the OBS meter and never reach the red.

Noise Suppression

Right-click the microphone in the Audio Mixer → Filters → + → Noise Suppression. It takes out fans and hum, which lowers the room under your voice.

Go easy on a noise gate

A hard gate cuts the start of soft words. The editor already measures your room, so a gate is rarely needed.

Think about the finished frame

Framing for the layout you want

Where you sit in the camera decides which of the two layouts will look right. You can use both in one project, so frame for the one you will use most.

Video-first

The video fills the frame, you sit in a shape

Your camera ends up small, in a circle or another of nineteen shapes. Frame head and shoulders, centred, with a little space above your head, so the shape crops to your face and not to your chin.

You-first

You fill the frame, the video sits beside you

The video plays in a window on your camera’s picture. Sit a little to one side and leave the other side empty, so the window has somewhere to go that is not your face.

The Files step with the demo project: your camera, with the person centred, and the video you react to, both ready and each with its own separate audio file
The demo project’s camera: head and shoulders, centred, so any shape crops to the face. For You-first, sit a little to one side instead.

A busy room is fine: the editor can remove the background behind you, so you stand in front of the video instead. See the template sets for both layouts on real frames.

Two minutes that save an evening

A twenty-second test

  1. 1
    Record twenty secondsSay a sentence, stay quiet for five seconds, say another. Play something through your headphones while you do.
  2. 2
    Play it backYou should hear yourself clearly and not hear the video at all. Your face should be lit and sharp.
  3. 3
    Drop it into the editorOn the Files step, your waveform should show the two sentences as clear bumps with a flat line between them. That flat line is what the automatic cut needs.
The real take

Recording the reaction

  • Start recording in OBS first, then start the video
  • Clap or say something on the video’s first frame: it makes syncing a two-second job
  • Let the camera run to the end. Trimming later is one drag; a missing minute is a re-shoot
  • React out loud: the cut follows your voice, and a silent reaction is a quiet clip

Next: line the two recordings up, then let the automatic cut do the first pass.

Learned the hard way

Mistakes that cost a re-shoot

Speakers instead of headphones

The video ends up inside your voice, and it cannot be taken out afterwards.

Desktop Audio left on

Same result by a different route: the computer’s sound is recorded under you.

A window behind you

The camera exposes for the bright window and your face goes dark.

No free disk space

An hour of 1080p camera is several gigabytes. Check before a long watch; MKV at least keeps what was recorded.

Questions about recording

Do I need OBS?

No. Anything that saves a video file works: a phone, the camera app on your computer, a camera with a card. OBS Studio is free and lets you choose the microphone, mute the computer’s sound and clean up noise, which is why it is the one we describe.

Should I record my screen and my camera into one file?

Not for this editor. One file with both bakes a layout in, and then there is nothing left to switch when you talk. Keep two files, your camera and the video you watched, and the editor builds the layout and the cuts for you.

MKV or MP4?

MKV. If the recording stops early, from a crash or a full disk, an MKV keeps everything up to that point and an MP4 can be lost whole. ReactionCut opens MKV directly, so there is nothing to convert.

What resolution should my camera record?

1080p at 30 frames per second is plenty for a face. The finished video follows the resolution of whichever recording fills the screen, up to 4K, so the video you react to decides the sharpness of most of the frame.

Can I record on my phone?

Yes. Record yourself on the phone, move the file to your computer, and add it as your camera. Watch the video on headphones connected to whatever is playing it, so its sound stays out of the phone’s microphone.

Recorded? Put it together.

Add your two files to the editor, or try the demo project first. Nothing is uploaded.

Open ReactionCut, free