# Mixer/Reverb Snapshot UE4 Integration not working. **URL:** \ **Category:** Unreal Engine\ **Created:** [July 3, 2016, 11:15am UTC](https://qa.fmod.com/t/mixer-reverb-snapshot-ue4-integration-not-working/12558 "2016-07-03T11:15:34Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![MikePatterson](https://avatars.discourse-cdn.com/v4/letter/m/ec9cab/32.png) [@MikePatterson](https://qa.fmod.com/u/MikePatterson)\ **Post date:** [July 3, 2016, 11:15am UTC](https://qa.fmod.com/t/mixer-reverb-snapshot-ue4-integration-not-working/12558/1 "2016-07-03T11:15:34Z")
Hello, and thank you for taking the time to read this! I really do appreciate it šŸ™‚ **TL;DR** : I canā€™t get Fmod Studioā€™s reverb snapshots to work correctly in Unreal Engine 4; the reverb tail is consistently cut off when Fmod Event is done playing. Current documentation on how to implement Mixer Snapshots into Unreal Engine 4 is outdated and not very helpful for troubleshooting. This might be a bug, so Iā€™m going to write this up as a bug. Sorry for the length and specificity of the Repro Steps, I just want to be as crystal clear as possible with my set up and what Iā€™m experiencing. Referenced **capture\_** images are linked at the bottom of this question. **STEPS TO REPRO:** 1. Extract the FMOD Studio UE4 Engine Integration for Windows/Android in Unreal Engineā€™s system Plug-In directory (in my case, this path is _C:\Program Files (x86)\Epic Games\4.12\Engine\Plugins_) (see **capture\_1.png** ) 2. Launch Unreal Engine 4 and create New Project using the First Person template. 3. Launch FMOD Studio and create a new project. 4. In Windows Explorer create a new folder named ā€œFMODā€ in your Unreal projectā€™s _Content_ folder. In my case, this path is _C:\UE4\_Projects\audio\_test\_02\Content\FMOD_. (see **capture\_2.png** ) 5. In FMOD Studio, open _Edit \> Preferences_ and navigate to the _Build_ tab. 6. Set the _Built banks output directory_ to the newly created folder named ā€œFMODā€ in your Unreal projectā€™s Content directory. (see **capture\_3.png** ) 7. Create a new single sound Event and remove the Reverb Send on the eventā€™s Master track. In my case, Iā€™m using a recording of a walkie talkie being clicked off. (see **capture\_4.png** ) 8. Assign Event to Master Bank. 9. In the Mixer window (Ctrl+2) create a Mixer Group and assign the Event mixer input to the new Group. Iā€™ve labeled my group SFX. 10. Add the following effects to the Mixer Group: Compressor, 3-EQ, and Send to Reverb. (see **capture\_5.png** ) 11. In the _Snapshots_ tab of the Mixer window, create a new overriding snapshot; Iā€™ve labeled mine _fmod\_long\_reverb_. 12. Select the Mixer Snapshot, right-click the Reverb Return track and select _Scope In._ 13. Change the _Reverb Time_ value of the Reverb effect to 10 (or some other noticeably large number). 14. On the Mixer Group (SFX in my case) Scope In the Reverb Send and the Fader Volume. 15. Make sure the Mixer Group and Reverb Return volumes are both set to 0 dB and set the Mixer Groupā€™s Reverb Send to -12 dB. 16. Make sure Reverb effectā€™s _Wet Level_ is set to 0 dB and _Dry Level_ is turned down to negative infinity. 17. Right click the _Intensity_ Snapshot Macro and Expose as Parameter. (see **capture\_6.png** ) 18. Save project and Build the Master Bank. 19. In your Unreal project, Create an **Audio Volume**. Iā€™ve labeled mine ā€œreverb\_volumeā€. 20. In the **Details** panel, under **Reverb \> Settings** , assign your Mixer Snapshot to the **Reverb Effect** parameter and make sure **Apply Reverb** box is checked. (see **capture\_7.png** ) 21. Switch to **Geometry Editing** mode (Shift+F5) and edit the size of the Audio Volume so that it encompasses the play area of the map. (see **capture\_8.png** ) 22. In Content Browser, open the **FirstPersonCharacter** Blueprint Class, located in _Content/FirstPersonBP/Blueprints_. 23. In the top right corner of the ā€œSpawn projectileā€ comment box in the bottom portion of the blueprint, replace the **Play Sound at Location** and **GetActorLocation** nodes with **Play Event at Location** and **GetActorTransform** nodes, wiring up the logic as the other nodes were wired up. Make sure the FMOD Event is selected under the Event pin of the **Play Event at Location** node. (see **capture\_9.png** ) 24. Save the Blueprint and the Unreal Map. The Blueprint might need to be recompiled. 25. In the map, press **Play** (Alt+P) to test the map. 26. Observe the reverb on the FMOD Event as you fire your weapon. **EXPECTED RESULTS:** When the gun is fired, the FMOD Event plays with a reverb tail of at least a couple full seconds. Since my _Reverb Time_ parameter in the mixer snapshot is set to 10, and the mixer groupā€™s reverb send is set to -12 dB in the mixer snapshot, I would expect to hear a reverb tail that lasts close to 10 seconds. **ACTUAL RESULTS:** When the gun is fired, the FMOD Event plays with hardly any reverb at all. If you spam the fire button you can kind of start to hear the reverb between the gun shots, but the reverb tail is abruptly cut off as soon as the Event is finished playing. It sounds like the reverb time was set to less than 1 second long. ā˜¹ **IMAGES:** - [capture\_1.png](http://i.imgur.com/0d9Qs7T.png) - [capture\_2.png](http://i.imgur.com/aWhRyIO.png) - [capture\_3.png](http://i.imgur.com/U0gtIsE.png) - [capture\_4.png](http://i.imgur.com/MLCp94r.png) - [capture\_5.png](http://i.imgur.com/HBi7fxK.png) - [capture\_6.png](http://i.imgur.com/QlIwkGa.png) - [capture\_7.png](http://i.imgur.com/JoNqwPq.png) - [capture\_8.png](http://i.imgur.com/p8x4ooI.jpg) - [capture\_9.png](http://i.imgur.com/ydbHhhk.png) **SOFTWARE VERSIONS:** Windows 7 Professional Service Pack 1 Unreal Engine 4.12.4 FMOD Studio 1.08.07, 64-bit, Build #77241 **HARDWARE:** Intel Core i7-4790 CPU @ 3.60 GHz 32 GB of RAM 64-bit Operating System ---
**Author:** ![geoff](https://avatars.discourse-cdn.com/v4/letter/g/a3d4f5/32.png) [@geoff](https://qa.fmod.com/u/geoff)\ **Post date:** [July 4, 2016, 4:15am UTC](https://qa.fmod.com/t/mixer-reverb-snapshot-ue4-integration-not-working/12558/2 "2016-07-04T04:15:19Z")
Firstly thanks for the very clear and thorough repro steps. The problem is the same one mentioned here: [http://www.fmod.org/questions/question/fmod-convolution-reverb-cutting-off-tail/](http://www.fmod.org/questions/question/fmod-convolution-reverb-cutting-off-tail/) That is, the event is finishing early and when it is destroyed, it is tearing down the mixer buses that are no longer referenced. The workaround mentioned in that case is to lock the mixer buses so their lifetime is guaranteed. To make that easy in the UE4 integration, the next patch release adds an option bLockAllBuses that can be used to keep them alive for the duration of the play session. ---
**Author:** ![MikePatterson](https://avatars.discourse-cdn.com/v4/letter/m/ec9cab/32.png) [@MikePatterson](https://qa.fmod.com/u/MikePatterson)\ **Post date:** [July 5, 2016, 4:15pm UTC](https://qa.fmod.com/t/mixer-reverb-snapshot-ue4-integration-not-working/12558/3 "2016-07-05T16:15:18Z")
> [@](#): > > Firstly thanks for the very clear and thorough repro steps. The problem is the same one mentioned here: > > [Fmod Convolution Reverb cutting off tail - FMOD Studio - FMOD Forums](http://www.fmod.org/questions/question/fmod-convolution-reverb-cutting-off-tail/) > > That is, the event is finishing early and when it is destroyed, it is tearing down the mixer buses that are no longer referenced. > > The workaround mentioned in that case is to lock the mixer buses so their lifetime is guaranteed. To make that easy in the UE4 integration, the next patch release adds an option bLockAllBuses that can be used to keep them alive for the duration of the play session. Hey thanks for the answer! Do you happen to know if Studio:šŸšŒ:lockChannelGroup can be called using Blueprints in UE4 or can it only be accessed using C++? ---
**Author:** ![geoff](https://avatars.discourse-cdn.com/v4/letter/g/a3d4f5/32.png) [@geoff](https://qa.fmod.com/u/geoff)\ **Post date:** [July 6, 2016, 12:12am UTC](https://qa.fmod.com/t/mixer-reverb-snapshot-ue4-integration-not-working/12558/4 "2016-07-06T00:12:24Z")
I havenā€™t added that one to Blueprints. ---
**Author:** ![MikePatterson](https://avatars.discourse-cdn.com/v4/letter/m/ec9cab/32.png) [@MikePatterson](https://qa.fmod.com/u/MikePatterson)\ **Post date:** [July 7, 2016, 6:46am UTC](https://qa.fmod.com/t/mixer-reverb-snapshot-ue4-integration-not-working/12558/5 "2016-07-07T06:46:38Z")
Geoff, thanks again for answering my questions, I really really appreciate it. Iā€™ve downloaded the FMOD Studio API for Windows and Iā€™m currently pouring over the Compiled HTML Help File to figure out exactly how to call Studio:šŸšŒ:lockChannelGroup on my reverb buses, as user Graeme Webb suggests. After reading through the help file, I feel like I have a fairly solid grasp on what the concept of the Channel Group even is, and the fact that it is a low level layer that routes regular Studio buses, including for example the Return bus Iā€™m using for my Reverb, but I have to come clean: Iā€™m really a very novice C++ user who just coincidentally happens to be in the process going through a beginning intro C++ programming manual before I even asked this question on here. Iā€™ve used FMOD Studio for a while now but I have yet to seriously use it with Unreal. Since the FMOD System is clearly being initialized somewhere from Step 1 of my Repro Steps listed above, (and the ā€œFMOD UE4 Integration.chmā€ Compiled HTML Help File currently doesnā€™t show any content on any of its pages, for some reason?), and Iā€™ve been handling FMOD Studio calls via Blueprints thus far, I am unclear as to how to call this very specific C++ function in conjunction with Blueprints. I havenā€™t needed to dig into any C++ code on my project so far, and according to the documentation for Studio:šŸšŒ:lockChannelGroup ([http://www.fmod.org/docs/content/generated/FMOD\_Studio\_Bus\_LockChannelGroup.html](http://www.fmod.org/docs/content/generated/FMOD_Studio_Bus_LockChannelGroup.html)), this function needs to be called in the ā€œasync threadā€ since by default FMOD Studio starts in asynchronous mode. Given that Iā€™ve implemented the FMOD Studio UE4 Integration packages in my Unreal Engine Plugins folder (as opposed to implementing it on a project-by-project basis), Iā€™m very unclear as to where this async thread is, or which file in my project is initializing the FMOD System. Ideally, from the documentation it seems like Iā€™m supposed to be able to call this function once after the system initializes and not have to worry about it, just set it and forget it. If this is the only reason I would need to write C++ directly, would you recommend creating a C++ source file specifically for this purpose? And if so, would I also need to initialize the FMOD System in this same source file? Or by contrast, is there an existing source file in my project that I can just edit directly and add a callback to this function? Thanks again for your fast responses! ---
**Author:** ![MikePatterson](https://avatars.discourse-cdn.com/v4/letter/m/ec9cab/32.png) [@MikePatterson](https://qa.fmod.com/u/MikePatterson)\ **Post date:** [July 7, 2016, 6:52am UTC](https://qa.fmod.com/t/mixer-reverb-snapshot-ue4-integration-not-working/12558/6 "2016-07-07T06:52:57Z")
Also, given what Iā€™ve stated above about my own C++ experience (or lack thereof), would you recommend that I use a previous version of FMOD Studio that doesnā€™t have this known bug? ---
**Author:** ![geoff](https://avatars.discourse-cdn.com/v4/letter/g/a3d4f5/32.png) [@geoff](https://qa.fmod.com/u/geoff)\ **Post date:** [July 12, 2016, 5:25am UTC](https://qa.fmod.com/t/mixer-reverb-snapshot-ue4-integration-not-working/12558/7 "2016-07-12T05:25:14Z")
Best thing to do is to wait until our next patch release, which will have the ā€œLock All Busesā€ setting to do it for you. Weā€™re hoping to get a build out by the end of this week. ---
**Author:** ![geoff](https://avatars.discourse-cdn.com/v4/letter/g/a3d4f5/32.png) [@geoff](https://qa.fmod.com/u/geoff)\ **Post date:** [July 27, 2016, 7:02am UTC](https://qa.fmod.com/t/mixer-reverb-snapshot-ue4-integration-not-working/12558/8 "2016-07-27T07:02:23Z")
The latest FMOD release has a setting to lock all buses.