How to Add an Audio Source to the OBS Mixer

Before you start

This task runs locally in OBS Studio on your computer. You do not need an online service. Have the audio device you want to capture connected and switched on before you open OBS, because the application may not always detect a device that is connected later. Close any other program that may be using the device exclusively, especially another recording app or a voice chat tool. Check your operating system sound settings if the device is already listed in OBS but does not produce a visible input level.

Step-by-step instructions

In OBS, the Audio Mixer section usually sits near the bottom of the main window. If it is not visible, open the View menu and enable Audio Mixer. The mixer shows one row for each audio source that is currently part of the active scene or globally available, depending on the selected source properties.

Add a microphone or other input device

In the Sources list, click the plus button and choose Audio Input Capture. Give the source a recognizable name, then select the input device from the Device list. In newer OBS versions you can also enable the option to use device timestamps; if you are unsure, leave the option in its default state. Click OK to add the source to the scene.

Add desktop or application audio as an output device

To capture sound coming from your computer, add Audio Output Capture. On Windows, select the output device that matches the playback route you want to record. On macOS and Linux, the available choices depend on the audio subsystem and any virtual device drivers installed. For the common desktop sound setup, choose your default output device if it is listed. OBS may also show application-specific capture options on some supported systems.

Adjust the source in the mixer

Find the new row in the Audio Mixer. The fader controls the output level sent to your stream or recording. The volume percentage text next to the fader shows the current gain. Right-click the mixer row or use the gear icon to open Advanced Audio Properties, where you can set the source to monitor only, output only, or both. Set monitoring carefully when using speakers, because it can create an echo loop.

Check the output

Speak or play sound and watch the meter for the new source in the Audio Mixer. The meter should move while the signal is active and stay near the bottom when the source is silent. Keep typical input level peaks out of the red zone to avoid clipping. OBS uses the project sample rate configured in Audio settings; sample rate differences between the device and OBS can sometimes be handled automatically, but the Audio settings page is where you verify the captured audio format.

Make a short test recording with the same output settings you plan to use. Listen back with the recording format and encoding settings you intend for the final file, because audible background noise or distortion may become more obvious after encoding. For a stream, run a short test with the selected bitrate and check downstream audio, not only the local meter.

Common problems and next steps

The source appears but the meter stays flat

Confirm the device is not muted in your operating system sound settings and that its system input level is high enough. Check that the device is not set to a different sample rate than OBS in a way that stops capture. Also confirm another application is not holding the device exclusively. After changing a device connection, remove and re-add the source in OBS if the application has not refreshed the device list.

Background noise or distortion

Lower the source input level before the signal reaches OBS when possible, then use the mixer fader only for the final balance. A tiny movement of the meter at silence is normal for some microphones. For noticeable room noise, place the microphone closer to the speaker. A noise suppression filter can help, but it is not a substitute for a clean input level. If distortion continues, check whether OBS is resampling the capture source and review the project sample rate.

The audio source is missing from the mixer

Make sure the source is added to the currently selected scene. If you record with a source that is in another scene, it will not be in the active mixer. In Advanced Audio Properties, check whether the source is set to output only, because monitor-only sources may still show in the mixer but be inaudible in the recording. For capture devices that disappear after sleep or reconnection, OBS often needs the source to be selected again before audio resumes.