# How to create illusion of source occlusion with reverb

**URL:** <https://qa.fmod.com/t/how-to-create-illusion-of-source-occlusion-with-reverb/23753>\
**Category:** Unreal Engine\
**Created:** [December 3, 2025, 9:14am UTC](https://qa.fmod.com/t/how-to-create-illusion-of-source-occlusion-with-reverb/23753 "2025-12-03T09:14:46Z")\
**Posts on this page:** 1\
**Showing post:** 2

<div class="post-metadata">

**Author:** ![jeff\_fmod](https://yyz2.discourse-cdn.com/flex036/user_avatar/qa.fmod.com/jeff_fmod/32/1766_2.png) [@jeff\_fmod](https://qa.fmod.com/u/jeff_fmod)\
**Post date:** [December 8, 2025, 11:36pm UTC](https://qa.fmod.com/t/how-to-create-illusion-of-source-occlusion-with-reverb/23753/2 "2025-12-08T23:36:23Z")

</div>

I think what you’ve done is generally the recommended starting point for occlusion. From here you can extend your system with:

- Transmission- by adding an LPF after the gain and ducking the highs when occluded, which matches real-world occlusion a little more.
- Diffraction- by dynamically adding transceivers to your cave entrances. There’s a discussion on this [here](https://qa.fmod.com/t/duplicate-mirror-event-in-unity/20795) in the context of Unity, but the same principles apply to Unreal.
- Reflection- by automating reverb and delay based on the dimensions of the room that the player is in. There’s a great example of this technique [here](https://www.youtube.com/watch?v=e33BYpZWaRo&t=280s).

If you are designing for narrow interiors, such as corridors and rooms, combining Unreal [Audio Volumes](https://dev.epicgames.com/documentation/en-us/unreal-engine/audio-volumes-in-unreal-engine) with FMOD [Snapshots](https://fmod.com/docs/2.02/studio/glossary.html#snapshot) (thus creating [reverb zones](https://fmod.com/docs/2.02/unreal/user-guide.html#reverb-zones)) can give you more control over occlusion and reverb characteristics for a given space- i.e walking past a window puts the mixer into one state, walking past a concrete wall puts it into another. It’s computationally cheaper without all the ray tracing, but it’s less generic since it’s harder to execute with exteriors.

Hopefully that gives you some inspiration on where to go next, and other possible implementations if you want to attempt them. Let me know if you have any more questions!

---

_[View the full topic](https://qa.fmod.com/t/how-to-create-illusion-of-source-occlusion-with-reverb/23753)._