Use the Audio Mixer device to adjust the volume for groups of sounds with dynamic and automatic control of a game’s volume mix, much like a professional mixing console would.
With the Audio Mixer, you can adjust the level of sounds that are already in Fortnite (such as weapons, character footsteps, and vehicles) as well as custom sound waves and sound cues by using control buses and control bus mixes.
The Audio Mixer is also available directly in Fortnite Creative. Check out the Audio Mixer Device for more info.
Jump to Activate Mix for a Duration for a step-by-step guide on activating a mix for a short duration on your island.
Control Buses
When a sound is set to use a control bus, all the sounds on that bus can be modulated together in a Control Bus Mix.
The following control buses are available to control the volume of the sounds that occur in Fortnite by default:
Control Bus Name | Description |
---|---|
CB FortAmbient | Used to set the volume of FN ambient sounds. |
CB FortExplosions | Used to set the volume of FN explosion sounds. |
CB FortFootstep | Used to set the volume of character footsteps. |
CB FortGadgets | Used to set the volume of sounds associated with FN Creative gadgets and devices. |
CB FortGlobal | Used to set the volume of all FN sounds. |
CB FortHitNotify | Used to set the volume of sounds associated with the Player getting impacted. |
CB FortImpacts | Used to set the volume of impact sounds. |
CB FortMusic | Used to set the volume of music (includes emote music). |
CB FortVehicles | Used to set the volume of vehicle sounds (not including engine sounds). |
CB FortVehicles Engine | Used to set the volume of vehicle engines. |
CB FortWeapon | Used to set the volume of weapons. |
You can also create your own control buses. To create a control bus:
- In the Content Browser, with the project content folder selected, click the +Add button or right-click in an empty space in the Content Browser to bring up a context menu.
- Under the Create Advanced Assets section, click Audio > Modulation, then click Control Bus.
- Enter a name for your new control bus.
- Open the Control Bus asset and set the Parameter to Volume
To use a control bus on custom audio assets, the control bus must be set on the sound wave asset. The sound wave can still be used on a sound cue and the effect will be applied.
To add a control bus to your sound wave:
- In the Content Browser, open the sound wave you want to add to a control bus to.
- Under Modulation, set Volume Routing to Override.
- Click the Modulate checkbox.
- Add one or more control buses to the Volume Modulators array.
Control Bus Mixes
Control bus mixes take a group of control buses and allow you to define the volume level for each control bus.
To create a control bus mix:
- In the Content Browser, with the project content folder selected, click the + Add button or right-click in an empty space in the Content Browser to bring up a context menu.
- Under the Create Advanced Assets section, click Audio > Modulation, then click Control Bus Mix.
- Enter a name for your new control bus mix.
Control bus mixes can also be created directly from the Mixer device.
Control bus mixes take an array of mix stages. Each mix stage has the following parameters:
Parameter | Description |
---|---|
Bus | A control bus. Can be a Fortnite-defined bus or a user-created one. |
Value | The volume of the sounds routed to this control bus should be scaled when a mix is activated. |
Attack Time (sec) | Attack is the time in sections for the mix to be applied when the mix is activated. |
Release Time (sec) | Release is the time in sections for the mix to be applied when the mix is deactivated. |
Finding and Placing the Device
- Open the Content Browser.
- Open the Fortnite folder index list.
- Open the Devices folder.
- Select the Audio Mixer device and click-and-drag the device into the viewport.
- Select the Audio Mixer device in the Outliner panel.
- Configure the User Options for the Audio Mixer device in the Details panel
User Options
This device applies a control bus mix when activated, and you can configure this device to set the value:
Option | Value | Description |
---|---|---|
Mix | None, Select a Control Bus Mix | The control bus mix to apply when the device is activated. |
Direct Event Binding
Devices in UEFN use Event Binding to communicate. To set direct event binding for your device in UEFN:
- Select the device in the Outliner panel.
- Open the Details panel.
- Navigate to User Options-Functions.
- Add an element to a function.
- Select a device to interact with.
- Set the function the device performs to send a trigger to the Audio Mixer.
Functions
A function tells the selected device what it needs to do when the triggering device performs an action.
Option | Value | Description |
---|---|---|
Activate Mix | Click the Add icon to select a device, then select an event. | Activates the control bus Mix when the selected device and event triggers the Audio Mixer device. |
Deactivate Mix | Click the Add icon to select a device, then select an event. | Deactivates the control bus Mix when the selected device and event triggers the Audio Mixer device. |
Register Player When Receiving From | Click the Add icon to select a device, then select an event. | When an event occurs, this function registers the triggering player to this device. |
Unregister Player When Receiving From | Click the Add icon to select a device, then select an event. | When an event occurs, this function unregisters the triggering player to this device. |
Unregister All Players When Receiving From | Click the Add icon to select a device, then select an event. | When an event occurs, this function unregisters all players from this device. |
Using the Audio Mixer Device in Verse
All Audio Mixer functions are exposed in Verse. You can now activate mixes, deactivate mixes and register/unregister players to a mix or bus using Verse.
# Copyright Epic Games, Inc. All Rights Reserved.
using { /Fortnite.com/Devices }
using { /Verse.org/Simulation }
using { /UnrealEngine.com/Temporary/Diagnostics }
# A creative device that allows an audio mixer to be toggled on and off via a button device
on_off_audio_mixer_device := class(creative_device):
@editable
AudioMixerDevice:audio_mixer_device = audio_mixer_device{}
@editable
Button:button_device = button_device{}
var MixActive:logic = false
# Runs when the device is started in a running game
OnBegin<override>()<suspends>:void=
Button.InteractedWithEvent.Subscribe(OnButtonInteractedWith)
OnButtonInteractedWith(InPlayer:agent):void=
if(MixActive?):
AudioMixerDevice.DeactivateMix()
set MixActive = false
else:
AudioMixerDevice.ActivateMix()
set MixActive = true
To use this code in your UEFN experience, follow these steps.
- Drag an Audio Mixer device onto your island.
- Create a new Verse device named audio_mixer_device_example. To learn how to create a new device in Verse, see Create Your Own Device Using Verse.
- Open Verse Explorer and double-click audio_mixer_device_example.verse to open the script in Visual Studio Code.
- Paste in the code above, compile, and drag the Verse-authored device onto your island.
- Select your Verse device in the Outliner.
- In the device’s Details panel, assign the object reference for the AudioMixerDevice to the Audio Mixer device on your island. You can use the eyedropper to pick the device in the viewport, or use the dropdown and search for the device.
- Save your project and click Launch Session.
Audio Mixer API
See the audio_mixer_device
API Reference for more information on using the Audio Mixer device in Verse.
Activate a Mix for a Duration
For this example, let's prototype a Hide and Seek game. Footsteps are muted while players look for a hiding spot, and once the timer runs out, everything is fair game! These four devices are required to test this example:
- Player Spawner
- Audio Mixer
- Timer
- Round Settings

-
Select and drag the Audio Mixer device into the viewport.
-
In the Details panel, assign CBFortFootstep in the Bus field.
-
Set Fader Value to 0.0.
-
Check Activate on Game Start.
-
Select a Timer device and drag it into your scene.
-
Customize the device settings as you see fit for your island. In this example, Duration is set to 30.0.
-
Select and drag the Round Settings device into the viewport. This example uses the default options.
-
Select the Audio Mixer device again and go to the User Options - Functions section.
-
Click + to add an Array element to Activate Mix
-
Select the Round Settings device and choose the On Round Start option.
-
Click + to add an Array element to Deactivate Mix
-
Select the Timer device and choose the On Success option.
-
Press on Launch Session and test your game! When a round starts, you should not be able to hear footsteps until the 30-second timer has run out.