What Is An Ambience?

Ambiences are the environmental and background sounds that underpin the overall soundscape of a game. They provide context for all the other sounds in a game, helping to create the impression of a living, believable world. Importantly, ambiences are more than just a continuous loop to fill the silence; they can be made up of multiple sounds and controlled dynamically to reflect the events of the game.

Consider a game like Ghost of Tsushima, which has lush ambiences full of diverse plants and wildlife - the developers can change the volume of different ambient sounds in response to the player’s location. For example, they may add more sounds to create a denser and more detailed ambience when the player is in a forest environment, but remove sounds and raise the volume of the wind when the player is in more open areas. The developers can also change the ambience as the player enters combat, removing certain elements (like for example songbirds) until combat is finished to create a contrast between the exploration and combat, as well as make room for other sound effects.

Ambiences can also be used to influence the player’s emotions and control the mood of a scene, using non-diegetic or wholly abstract sounds such as synth drones to create unnatural atmospheres or instil a sense of imminent danger. Horror games in particular make frequent use of these techniques to unnerve the player and build tension during quieter moments.

In short, creating effective ambiences is a mixture of both sound design and implementation, and mastering these techniques is key to creating immersive soundscapes.

What Is An Ambience Made Of?

The ambience of a game is comprised of multiple different elements that are combined and adjusted in real time to create a dynamic and believable world. These elements include:

Ambience Beds

These are the foundation that the rest of the soundscape is built upon. Ambience beds are usually made up of a variety of stereo loops like room tones, wind, the hum of a city, distant traffic, etc. They provide a background for all the other sound effects and help them sit nicely in the mix.

Spot Effects

These are sounds that are spatialised, **meaning that their volume and stereo pan change depending on where they are in relation to the audio listener. They are often part of specific game objects like a clock, a refrigerator or windchimes. However, they can also be spawned into the world to cover clusters of game objects like a crowd of people or a bunch of leaves rustling in the wind.

Dynamic Changes

In AAA games, ambiences are often dynamic, changing over time based on factors such as a day/night cycle, weather, or through the players’ actions. In less complex games, or ones with smaller budgets, the ambience systems are simpler yet still effective.

Try It For Yourself!

This awesome website allows you to create your own ambience by blending various sound elements and layers. I highly recommend spending a few minutes experimenting with it and seeing what kinds of different environments you can create: https://mynoise.net/NoiseMachines/primevalEuropeanForestSoundscapeGenerator.php

Environmental Vs Abstract

The two main elements of an ambience are environmental sounds and abstract sounds.

Environmental sounds - as the name suggests - come from the environment, for example cars, birds or wind. They are the ‘real’ sounds that help make the world believable and bring it to life.

Abstract sounds, on the other hand, are non-diegetic sounds that are not connected to the game’s environment. They are often added on top of the environmental sounds to accentuate and influence the player’s emotions, creating tension or reinforcing the narrative.

I highly recommend checking out this 20-minute GDC talk from Joanna Orland, who does an amazing job at breaking down how ambiences work: https://www.gdcvault.com/play/1388/Bringing-Ambience-To-The-Foreground

How To Make An Ambience

Research & Explore

The first step in creating great ambiences is to familiarise yourself with the various environments of the game. If the game doesn’t have finalised art in it yet, then use concept art as your starting point, to get you a feel for the mood of the location.

Once you’ve done that it’s time to research - find some references from various real-world and game locations and go explore, writing down what you hear. Make a list of assets that you’ll need for each location, being sure to listen out for the small details, as they make all the difference in creating effective ambiences.

Find & Record Source Material

With our asset list compiled, the next step is to find and record source material. Make sure to take the weather and time of day into consideration when you’re recording, as they will have a huge impact on the soundscape you’re trying to capture.

For the ambience beds, you’ll want to capture lots of long stereo loops with very few detailed sounds, such as dogs barking or a door being slammed shut. It’s important to avoid having these kinds of detailed sounds in your ambience beds where possible, because they will become familiar and recognisable to the player as the ambience bed repeats, giving away the fact that your ambience is just a stereo loop and breaking the immersion.

Where necessary, detailed sounds are usually edited out of ambient loops and recorded separately, to be added later as spot effects. Adding these sounds as independent audio events allows us to randomise their timing and avoid creating obvious repetition in our ambiences.

When recording sounds for the spot effects, it’s important to consider the distance at which they will be heard. Sometimes, it might be worth recording the same sound from different distances (e.g. a recording done up close, a middle-distance recording, and a far-away recording); you can then switch between these recordings in response to the player’s location, creating a more natural and authentic sound than would be possible using just filters and attenuation.

These short behind-the-scenes videos from Dr Rev. Bradley Cooper (Audio Director on Ghost of Tsushima) offer some great insight into the recording process, as well as a super-creative method for sourcing bird sounds.

Recording the ambiences of Ghost Of Tsushima: https://vimeo.com/572705594

Creating fake birds for Ghost Of Tsushima: https://vimeo.com/549154902

Edit, Layer & Process

After we’ve recorded and gathered our source material, we can begin editing, layering and processing to create our sounds. The main goal of editing is to remove any unwanted noise, resonant frequencies, or sounds from our recordings. This is typically done using subtractive EQ and noise reduction plugins such as iZotope RX, as well as the standard editing tools in our DAW.

Layering sounds helps us create better and more unique soundscapes, but it can be important to avoid layering too many sounds with very similar frequency content. For example, if you layer 3 wind sounds on top of one another, which all mainly sit in the low-frequency range, the resulting sound will be muddy and indistinct. This can be avoided by using EQ to remove any excess frequency content from sounds, but also through choice of layers, combining sounds that have different frequency content and are less likely to clash.

Processing is all about experimentation. The goal is to make it sound good in the context of the game, and there are no rules. Remember: “If it sounds good, it is good.”

Here is a great tutorial from Tyler of Aftertouch Audio on how to design ambiences in your DAW: https://youtu.be/8KqTkXQRnbs

For more information about editing, layering and processing, check out the Sound Design Techniques chapter of the Learning Roadmap, under Sound Design Basics.

Summary

Ronny Mraz from Avalanche Studios illustrates the process of building an ambience in this excellent article for Splice, including some implementation advice for those of you interested in technical sound design: https://splice.com/blog/audio-soundscape-for-video-games/

How You Can Make Better Ambiences

Practice makes perfect, and so naturally a great way to get better at creating amazing ambient soundscapes is to make lots of them within your DAW. However, there is another way to improve which you can do anywhere, and only requires you to be able to take notes on paper or a device of your choice. I call this method S.L.A.B.

S.L.A.B.

SLAB stands for Stop, Listen, Analyse and Breakdown. The idea behind it is that at any given point, whether you’re on a walk in nature, in a coffee shop or on a train, you can stop and listen to your environment carefully.

Close your eyes and analyse what you hear. Take in all of the small details, like leaves scraping along a street in the wind, a fence gate rattling, dogs barking in the distance, etc. Now write down a list of all the things you can hear, and consider how you would play them back in a game ambience - are there continuous droning sounds like an ambience bed? What kinds of sounds would you add as spot effects, and how frequently do you hear them?

If you want to go a step further you can think about how the soundscape will change with the day and night cycle, as well as the changing weather.

Ambience Implementation (Technical Sound Designer)

There are a lot of different ways we can implement sounds to create ambiences. We’ll be focusing on some of the most common ones to provide you with a basic toolset.

Ambient Zones

We can change the ambience by setting up “ambient volumes” or “ambient zones”. They are essentially three-dimensional boxes that we can adjust and sculpt to fit within a game’s environment. We can then set these ambient zones to play different sound files, creating unique mixes for different parts of the game as the player (or the audio listener attached to the camera) enters them, for example a forest ambient zone with trees rustling, birds, wind and animal calls.

Scripted Events

We can use scripted events like a boss encounter, a cutscene, or other hard-coded gameplay moments like a state change (going from exploration to combat) to change our ambience.

For example, if you wanted to bring down the ambience during a boss fight to make space for the music and combat sounds you could do this with a scripted event. It would tell the ambience to play back at a reduced volume change for as long as we are in that combat encounter, before returning to its original volume when the encounter ends.

Parameters

Parameters are values based on game data which we can make use of to change our ambience on the fly. These include things such as camera height, time of day, weather type, whether or not the player is in combat, or a health or stamina bar.

For example, think about how you would change the ambience based on the camera’s zoom level in a game like Sim City - as the camera zooms out we’d want to lower the volume of birds, cars and city noise and raise the volume of the wind, maybe also bringing in a more abstract, diffuse ambient layer. We can do this by using the distance of the camera or audio listener to the ground to control the volumes of the individual birds/cars/city noise/wind elements, either increasing or decreasing in volume as the camera gets further from the ground.

Emitters

Audio emitters are placed in the world and often bound to game objects, so that when environmental artists and level designers build and decorate the levels they automatically populate them with sounds. For example, an in-game asset of an air conditioning unit may have an emitter attached that plays a humming sound as the player gets close to it.

Emitters are often used for spatialised sounds like a tap dripping, a radiator humming or the sound of a TV. However, a common trick is to gradually reduce the intensity of any spatial effects as the player gets closer to the emitter, until you are left with a ‘2D’ stereo sound with no spatial information when the player is right next to it. This is useful for large objects that make a lot of noise such as heavy machinery or a waterfall, where you want the sound to envelop the player when they are near the source.

Splines

A spline is essentially a line made by connecting multiple points. This can be very useful to us when we have game objects that are irregular shapes.

Take for example a winding river, that you want to implement the sound of. Instead of placing multiple audio emitters or ambient zones along the river, you can instead draw a spline through the middle of the river and attach a single emitter to it. Then, as the player walks alongside the river, the emitter travels along the spline to follow them, playing back the river’s sound effects whenever the player is nearby. This is great for saving time, memory and processing, as we only have to use a single asset as opposed to lots of emitters.

Creating An Immersive Acoustic Environment

To help make environments more believable, games model the acoustics of the real world in slightly simplified ways. This allows us to simulate and adjust the characteristics of the sounds in real time while the game is running. We’ve largely covered all of these effects but here is a quick refresher of the tools that are available to us:

• Reverb & Delay

  Infuses the characteristics of the space into the sounds.

• Attenuation

  Creates the illusion of a sound being closer or farther away by changing parameters such as the volume or frequency content (high and low end) of the sound.

• Obstruction & Occlusion

  Simulating the path the sound takes to travel from the source to the player. If a large object is blocking the way then you will hear a slightly more muffled sound but a clean reverb (Obstruction). If there is a wall between the sound source and the player then we get a very muffled sound as well as a muffled reverb (Occlusion).

• Rooms & Portals

  Portals are openings that allow sound to travel from one space to another (like doors, windows or holes in the wall). If a sound is coming from inside one room but the player is in another then the portal will make the sound come from the right location, in this case, the closest portal to the player.

Advanced Learning Resources

An excellent video by Cujo Sound showcasing some of the ambience implementation in The Last Of Us Part 2: https://youtu.be/SOyGuk5yVKE

A GDC talk from Alex Previty and Blake Johnson of Insomniac Games - Designing the Bustling Soundscape of New York City in 'Marvel's Spider-Man’: https://youtu.be/idGHSezExTs

The team behind the Dead Space remake demonstrating how they used obstruction, occlusion and portals to bring the world to life: https://youtu.be/yMQOkpZO5eM

Designing an interactive ambient sound system in Wwise by Chang Liu: https://blog.audiokinetic.com/game-of-thrones-interactive-environment-sound-design/

How to set up ambient zones in Unreal Engine 4: https://docs.unrealengine.com/4.27/en-US/WorkingWithAudio/AmbientZones/