AAA Game Audio Hacks: Ducking

How do AAA Studios think about audio?

Indie dev: "I can't hear the sound effect... Crank the volume!"
AAA dev: "I can't hear the sound effect... Let's make space for it."

When we think AAA audio, we probably conjure up thoughts of 15-person audio teams working in multi-million dollar audio facilities. We also think about the games that made our childhood and the lasting memories they made in our minds. Undoubtedly, audio was key to this experience.

Our goal in this guide is give you the tools to be able to create without limits and compete with the likes of your favorite mainstream titles.

Audio Ducking will make your game sound awesome.

One of the most underutilized sound design techniques is something called audio ducking. The best way to describe audio ducking is momentarily turning down the volume of certain sounds to make room for others. This is something you'll find in AAA titles like God of War Ragnarök, The Legend of Zelda: Tears of the Kingdom, and Marvel's Spider-Man 2 - but very rarely will you find it used in an indie title.

But going along with our ethos, we believe this is something every game developer should know about! 

Let's get started.

Simple Audio Ducking in Unity

First, you’ll need to set up some AudioMixers.
Right Click in your Project Files,
Click Create >  Audio Mixer.

Once your Mixer is Created, Double click on it to open the Audio Mixer Window.

 → 

(Double click!)

Create a New Group via the Groups “+” Button, and name it  “Ducking”.

Once you’ve got both a “Master” and “Ducking” group, Configure each of your Audio Sources to use one of these two groups.

You can do this by selecting your Audio Source, Pressing this “Selector” button on the Output setting,

And Choosing whichever Group corresponds with this Audio Source.

Once you’ve assigned all related Audio Sources to the Correct Group, Open your mixer again and add a New Snapshot – Name this one “Ducked”.

 The changes you make to your groups are saved to the currently selected Snapshot.

When ducking audio, we want to lower the volume of the Master Group, and raise the volume of the ducked group.

Do this while the Ducked snapshot is selected – Lower Master and Raise Ducking.

Now, all we’ll need to do is trigger Ducking.

You can do this manually by writing your own AudioMixer Interaction script, but here’s a component that manages that for you: 

DuckController.cs

Once you’ve assigned your Mixer, toggle “Ducking” on or off to transition between the two states. You can even animate it, perfect for cutscenes.

Simple Audio Ducking in Godot

First, you’ll open the Audio Panel and add a new bus.  Name this bus “Ducking” and save. 

Find all your Ducked AudioStreams and change their bus from Master to Ducking. 

Now all we need to do is transition our busses based on the desired ducking effect!

Add our script, DuckUtil.gd to your project, and you’ll be able to use 2 simple functions:

DuckUtil.StartDucking(time),

And

DuckUtil.StopDucking(time).

Simple Audio Ducking in Unreal

First, Create a “Master” and “Ducked” Sound Class within your project files,
via Right Click > Audio > Classes > Sound Class

Additionally, Create a Sound Class Mix Specifically for dubbing.

Open Up your Ducked Sound Class Mix,
and add two items to its “Sound Class Effects” List.

Set the first Effect’s Sound class to Master, and half its volume;
Set the second Effect’s Sound class to Ducking, and double its volume.

Additionally, Adjust the ducking SoundMix’s fade in & fade out time at the bottom:

Save and Close your Sound Mix. Find each and every ducked and non-ducked audiosource in your Level, and assign the appropriate Sound Class into “Sound Class Override”

Either “Master” or “Ducked”.

Now, Simply use the “Push/Pop Sound Mix Modifier” nodes to Enable/Disable Ducking:

Audio should accordingly adjust volume depending on when and how you toggle ducking.

Anyways

We hope this guide has sparked some new ideas (and maybe made the world of game audio feel a little less intimidating). Having tools like this in your back pocket makes a world of difference. The truth is, AAA audio isn’t about having a massive team - it's about approaching situations with creativity and simplicity. 

And we’re here to keep showing you how. We've got more on the way. 

Keep creating. We’ve got your back.

-Neptune and Mars

P.S. I kept reading it as duckling. 🦆