OBS audio echoes or plays twice: find the duplicate capture path

Isolate one sound before changing filters

This is a documentation-based diagnosis, not a tested fix for every audio interface. Keep the original scene and device settings available so you can restore a missing source after a comparison.

Check global devices against scene sources

In Settings → Audio, note the devices selected globally. Then inspect the audio input and output sources in the active scene. A microphone selected globally and also added as a scene source can supply two copies of the same sound. OBS explicitly warns about this in its Audio Sources guide.

Choose one intended route for that device. For example, if the microphone should exist only in selected scenes, keep the scene source and disable its duplicate global entry. If every scene needs the same microphone, the global route may be simpler. Check the next scene before going live: removing a duplicate from one scene should not silently remove the only microphone in another.

On Windows, check application audio overlap

If you capture a game's audio individually, a global Desktop Audio source may also capture it. OBS's Application Audio Capture Guide advises disabling global Desktop Audio when using individual application sources to avoid echo.

Do not make that switch until you have accounted for every sound the audience needs. An alert, call participant, or music application that depended on Desktop Audio needs an intentional route too.

Windows application capture was introduced in OBS 28 for Windows 10 version 2004 or later and Windows 11. OBS 30.1 added audio capture alongside Game/Window Capture. Those source options are not a universal macOS setup instruction.

Distinguish monitoring from output

Hearing your microphone in headphones does not establish that the recording contains an echo. Monitoring is a listening path, while the saved or streamed output is the result to evaluate.

OBS developer Lain explains how monitored audio can be captured again by Desktop Audio in the official forum explanation of audio monitoring. The practical question is whether OBS is listening to the device that plays its own monitored sound.

Review Edit → Advanced Audio Properties and the configured monitoring device. Change one monitoring route for the trial and listen to the saved recording. Do not select a mute-output monitoring mode merely because its name sounds like an echo fix; that can change what the audience receives.

Use a small routing checklist

After the duplicate is resolved, balance levels using the OBS Audio Mixer Guide. A louder or quieter copy is still a duplicate; fader changes can conceal the symptom without simplifying the routing.

When to ask for help

If a single isolated input still sounds doubled, include the interface, operating system, OBS version, monitoring device, and routing diagram in a request through the OBS Help Portal. Note whether the problem is audible only in headphones or also in the recorded file. External mixer and driver routing need their own documentation.