Fader removes height with 3D Object Spatializer

Hi everyone,

I want to make my project Dolby Atmos ready. I modified the 2.01.09 UE4 Integration with the Spatial 7.1.4 settings available (the code is available inside FMOD GitHub repo). With Dolby Access installed and configured, following this tutorial by Dolby (Getting Started in Dolby Atmos with FMOD on Vimeo) when I launch my game, my AVR recognizes the signal and switch into Dolby Atmos mode. After that in FMOD Studio, I simply used a sound with Spatializer Effect and Height set to maximum. Playing in Studio : sound on my roof speakers OK. In UE4 : sound on my roof speaker OK.

The thing is when I switch from channel based approach to dynamic object with 3D Object Spatializer. In Dolby’s tutorial, the guy is putting the effect AFTER the fader effect and when I do that, no matter where up is my sound, it’s rendering in 7.1.

The thing is, if you put 3D Object Spatialzer BEFORE fader effect, now it totally works. I can move my object around my camera and it’s sucessfully panning on all the channels.

Is this an error of Dolby or is the 3D Object Spatializer not working correctly ? And after that, with sound consume before fader, how can I set things like volume or can I even add an effect before 3D Object Spatializer effect ?

Best regards,


When I test here, the position of the object spatializer in the signal chain relative to the fader makes no difference. I must therefore be doing something differently to you.

Tell me, to what output mode is the track that contains the audio content set?

Do the object spatializer meters that represent the four height channels indicate that they’re playing content when the spatializer is to the left of the fader? What about when it’s to the right?

I would rather sending you a copy of my Studio page :

And if I put the object spatializer after the Fader, the “Send” bus is also updating. But if I ask Unreal to play it, I only have my roof speakers playing if I put 3D Object Spatializer before Fader.

I have reproduced the event shown in your screenshot. However, dragging the object spatializer to the right of the fader has no effect on the height channels; they remain empty regardless of the object spatializer’s position in the signal chain.

Given that there appears to be no content in the event that produces an audible signal on the .4 channels, this is the expected behavior.

You didn’t mention the send bus before. What is this bus, and where does it get its input from?

The Send bus is the one inside the 3D Object Spatializer :
Capture d’écran 2021-04-28 085146

And it’s normal because we can’t simuate panning with 3D Object Spatializer inside Studio. The only way to test it is to create an actor with an FMOD AudioComponent inside it. Then you go to Unreal. Put that actor up to the listener (your camera ou controlled pawn) and then when in PIE or in packaged game if the 3D Object Spatializer is after the Fader, we hear nothing on the roof speakers. If the 3D Object Spatializer is before Fader, I’ve got sound on my roof speakers.

That is not a bus. It is a set of meters.

The object spatializer bypasses all FMOD Studio buses by sending its signal directly to hardware.

You are mistaken. There are a number of ways to simulate panning inside FMOD Studio. One of the most common is to use the 3D Preview widget in the event editor window’s overview pane: Dragging the dot in the center of the 3D preview changes the event instance’s Z and X co-ordinates for the purposes of auditioning, and holding down the Ctrl key or toggling the Front button allows you to move the event instance along the Y axis as well.

Got it thanks :slight_smile:

So the problem would come from the UE4 Integration of Fmod ?

I really don’t know about this problem, but as a workaround, if you have to put the spatializer before the volume fader, you could still set your volume (and additional effects) by adding a (sub-master bus) track and routing all your tracks to this sub-master, on which you will set the wanted volume. Or you could set each individual track (or instrument) volume.

I am honestly not sure what the origin of this problem is, as I have not yet been able to reproduce it.

I do doubt that the position of the object spatializer in the event’s signal chain is the cause, as if it was I would have reproduced the issue by now. It’s possible that there are additional conditions that must be met for the issue to be reproduced that we have overlooked, or that the bug is actually caused by something else unrelated to whether the object spatializer is pre- or post-fader. Still, until I can reproduce the issue, it’s hard to be sure.

You could also use a gain effect. Gain is an extremely cheap effect, so if you want to avoid making substantial changes to your event but still need volume automation, a gain effect is probably cheaper and easier than adding a new audio track just for the submix or moving your volume adjustment to multiple other tracks or instruments.