How to Add StreamElements Alerts to OBS Without Duplicates

An alert looks right in the browser, but in OBS it appears behind the game, plays twice, or is too loud. Divide setup into three tasks: create one AlertBox, add it to the scene, and check both picture and sound. Elaborate styling can wait until the basics work.

This approach uses a separate alert overlay. It is convenient when the same events need to appear in several scenes.

Create one AlertBox

Open My Overlays in StreamElements and choose New overlay. Set dimensions to match your scene. In the editor, add Alerts → AlertBox, enable the event types you need, and save.

Choose a clear name, such as “Alerts—Main Stream.” For the first pass, keep one simple event style so you know which version you are testing. Note its image, sound, and duration separately rather than trying to remember changes.

Event settings let you change the image, sound, text, position, and duration. Check enabled variations: changing the main alert does not automatically change every variation. Configure them or disable the ones you do not need.

Connect the overlay to OBS

Choose Copy URL from the overlay menu. In the selected OBS scene, add a Browser source and paste the link. Its width and height should match the overlay dimensions—for example, 1920 × 1080 for an overlay of that size. Put the source above elements that might cover the alert.

Keep the overlay link private. Hide the URL field before taking a settings screenshot you intend to share publicly.

For other scenes, copy the existing alert source. Do not leave another AlertBox inside a decorative overlay in the same scene: the same event may play again.

Work out who hears the sound

The official instructions suggest enabling Control audio via OBS in the browser-source properties. Its volume can then be adjusted in the mixer. To hear it yourself, use Monitor and Output in Advanced Audio Properties.

Check routing: if monitored audio is captured again by desktop audio, it may create a duplicate. Do not enable local monitoring merely so viewers hear the alert; first identify where sound is needed in your setup.

Check one symptom at a time

Make a short test recording and note whether the image appears in the right place, the name is readable, the sound does not overpower your voice, and the event plays once. Repeat while switching between main scenes. This is an editorial checking sequence you can adapt to your broadcast.

If you hear an event but cannot see it, check source order first. If nothing happens, confirm that the link came from the correct overlay, the dimensions match, and alerts are not paused in Activity Feed.

For doubled audio, temporarily leave only one alert source in the scene being tested and trace the audio path. Change one setting at a time and repeat the same test. You can then confirm the cause is fixed before restoring the other visual elements.