procedural game audio Asbjoern Andersen


How do you keep your game audio varied – without needing countless individual audio files? Procedural sound design can help with exactly that, and in this hands-on guide, senior lecturer, teacher fellow and author of the Game Audio Implementation book, Richard Stevens, demonstrates how the concept works in the Unreal Engine.

When creating a sound effect for a movie you’ll know that the audience is only going to hear it on one specific occasion, and you’ll likely build it up through editing and layering different sound elements to get just what you want.

01_game_audio_Explosion

Figure 01 ‘An explosion’

 

Most games, like sports, are about skill and mastery, so the player will be repeating similar actions again and again, and consequently they will be hearing the same sounds again and again. The trouble is that we’re very sensitive to this kind of repetition, since it just doesn’t happen in real life.
 

Video Thumbnail

Video: Explosion Baked


 
The obvious answer is just to have loads and loads of sounds but it would be far too much work to create 30-40 versions of every sound in the game (plus there are obviously limitations as to how much we can fit on a disk!).
If we look at our ‘explosion’ sound again we can see that the final sound is made up of different characteristic components, and this idea is key to starting to think about procedural approaches to sound design.

02_game_audio_Explosion_Components

Figure 02 ‘Explosion Components’

What we want to do is to keep these components separate when we import them into a game so that we can recombine them in different ways at run time. A lot of sounds in games aren’t ‘sounds’ at all, they are systems of sounds. This kind of procedural approach requires a different way of thinking, and sometimes different kinds of sound assets, since we often want to isolate the individual components that make up a sound.

When we bring these components into a Sound Cue in the Unreal Engine we can build a system of playback, and by having a few different versions of each component we can randomly combine them to create variation.

03_game_audio_Procedural_Explosion

Figure 03 ‘Procedural Explosion’

 

Video Thumbnail

Video: Explosion Components


 
By taking this approach we don’t need thousands of complete sounds in our game to be able to get thousands of different sounds out of the system. Randomizing the combinations of layers can vastly increase the number of potential outcomes with only a few additional sounds.

By taking this approach we don’t need thousands of complete sounds in our game to be able to get thousands of different sounds out of the system

In the above example we have four sets of three possible sounds that can potentially be heard so this will give us 81different sound outcomes. If we added just one other ‘Crack’ element then we’d get 108 potential sounds.


WANT MORE LIKE THIS?
FOLLOW A SOUND EFFECT FOR THE LATEST IN FANTASTIC SOUND:
 
          

We can increase this variation even more by adding some slight randomized delays and modulations of pitch and volume to each element, giving us.. erm… a very large number of possible outputs.

04_game_audio_Delay_Mod

Figure 04 ‘Adding Delay and Modulation nodes’

Video Thumbnail

Video: Explosion Delays and Modulation


 

Another thing we might want to do is to change the sound depending on what was being blown up, or the materials of nearby objects. Again by keeping these material components separate we can choose to layer them into the Sound Cue when appropriate by using a switch.
 


Popular on A Sound Effect right now - article continues below:

 

Latest releases:  
  • Foley Angry Door 192 Play Track 1400+ sounds included, 103 mins total $42 $37.80

    The doors are very kind, but don't make them angry. They could lose their temper resulting in a very noisy bang.

    This library enriches the sfx world with new door and gate objects, both source and designed, with variety of expressive actions and perspectives. The everyday usual noises along with fantasy stimulating sounds – e.g. deep “dungeon” metal door, high pitch squeaking wire-netting gate, heavy church gate and so on. To make the slams and smashes even more hard, heavy and dirty, wildly designed “Angry” versions have been added.

    Library highlight:

    18 door and gate objects, recorded in old, gloomy houses and a church
    • 6.29 GB, 645 files, several takes for each action
    • “Close-Up”, “Near”, “Middle” and “Behind” perspectives in selected cases, plus mix of them
    192khz/24 bit including ultrasonic information- the greatest resolution for next design processes
    Sound Devices MixPre6, Sanken CO100K, Sennheiser MKH30, DPA 4007, DPA 4060, Schertler Dyn Uni P48
    Photo reference for each object
    10 %
    OFF
    Ends 1553814000
    Add to cart
  • Industrial Motor Fan Play Track 76+ sounds included $58 $40.60

    MOTOR FAN household edition features both Internal & External mechanical sound from household items.
    Motors and compressors found in the kitchen, ACs & outdoor units + heaters and compressors and more.

    Features motor, fan & compressor sounds from sources like:

    Refrigerators, microwaves, toasters, juicers, fans, AC / hvac, washing machines, boilers, compressors, vents, heaters, chain saws & more
    30 %
    OFF
    Ends 1553986800
    Add to cart
  • Igniter is the new industry standard for creating any real-world or sci-fi vehicle and engine sound effects with ease and at unbeatable value. Whether you work in audio post or game audio, Igniter enables you to design, perform and automate any complex vehicle behaviour directly in your DAW – from sports cars, motorbikes, planes, helicopters, spacecraft and other engine sounds to moving ambiences, textures, Foley or whatever sparks your imagination.

    Video Thumbnail

    Igniter is the only solution of its kind to come jam-packed with over 20 performable vehicles and 1,943 audio assets from vehicles including Aston Martin, Ferrari, Porsche, Tesla, Harley Davidson, Huey UH-1H, Agusta Westland 119x, CH-47D Chinook, Bombardier Challenger, Cessna 560XL, skids, sweeteners and much more. Recordings come from Watson Wu, The Recordist, Sounding Sweet, George Vlad, Echo Peak and Flysound.

    For vehicle fanatics, Igniter Full Tank comes with 75GB of additional library content including onboard recordings, ramps & static rev bands, Foley sounds, skids, slides and much more!

    Add to cart
  • Igniter is the new industry standard for creating any real-world or sci-fi vehicle and engine sound effects with ease. Whether you work in audio post or game audio, Igniter enables you to design, perform and automate any complex vehicle behaviour directly in your DAW – from sports cars, motorbikes, planes, helicopters, spacecraft and other engine sounds to moving ambiences, textures, Foley or whatever sparks your imagination.

    Video Thumbnail

    Igniter is the only solution of its kind to come jam-packed with over 20 performable vehicles and 614 audio assets from vehicles including Aston Martin, Ferrari, Porsche, Tesla, Harley Davidson, Huey UH-1H, Agusta Westland 119x, CH-47D Chinook, Bombardier Challenger, Cessna 560XL, skids, sweeteners and much more. Recordings come from Watson Wu, The Recordist, Sounding Sweet, George Vlad, Echo Peak and Flysound.

    Add to cart
  • Aircraft - Jet/Propeller Planes F16 Maneuvers Play Track 70 sounds included, 45 mins total $39 $27

    The F16 Maneuvers library features 36 recordings of F16 Fighter jets, captured at three different locations from the ground perspective. In addition to those, we included :

    – 22 flight formation sounds (up to six aircrafts), designed using Sound Particles 3D software.

    – 8 recordings captured using contact microphones, attached in a nearby parked vehicle, leading up to some low tones and rumbles, that could be useful as sweeteners in aircraft or other complex sounds.

    – 4 mixing sessions, combining ambient and contact mic recordings.

    The product includes a total of 45 minutes of HQ material (24bit/96kHZ) and a total of 70 sounds, including 17 Soundminer metadata fields, such as description, keywords, category/sub-category, microphones and more.

    31 %
    OFF
    Ends 1553814000
    Add to cart

Win sound effects:
Here are 6 (!) chances to win incredible SFX libraries from Mindful Audio:
Get 6 chances to win here
Need specific sound effects? Try a search below:
 

By getting information from the game about what type of material is being blown up we can use this to control the switch, and therefore which material components of sound get added to the overall explosion sound.

05_game_audio_Explosion_Materials

Figure 05 ‘Explosion Materials’

Thoughts on the term ‘Procedural Sound Design’:

In writing the book we made a conscious decision to term this kind of sound design, that is typical in the current practice of game audio, ‘Procedural Sound Design’ to differentiate it from ‘Procedural Audio’.

Andy Farnell, who coined or at least popularised the term ‘Procedural Audio’ sees it as any kind of system where the sound produced is the result of a process. He describes these ideas more fully here. So under that definition, as soon as you set up any kind of system of playback you could see it as being procedural audio.

However there has been a lot of important work and progress in terms of procedural audio for games in the last few years (see http://proceduralaudionow.com/), and this has encompassed a variety of techniques, but there has been some emphasis on the idea of these procedural systems being synthesis based, which ultimately is probably the most flexible solution for interactivity.

This is a specialist field which we don’t go into in any depth in the book since there are other great books out there on this (not least Andy’s book ‘Designing Sound’). In the book we attempt to describe the range of procedural approaches by saying, “This approach to sound design exists on a spectrum from procedural sound design, where we tend to be manipulating pre-existing assets, to procedural audio, a term more frequently used when systems of synthesis are used to generate the sounds themselves (with much in between that combine both approaches)”.

To throw another thing into the discussion, when discussing music systems we also use the term algorithmic, which again could be used to describe any kind of system of playback. Although we could just call this procedural music (as others such as Karen Collins have done), but we felt it worth preserving and highlighting ‘algorithmic’ given the long history of algorithmic techniques explored for music in the past, which a search for ‘procedural music’ is going to miss.

 

Video Thumbnail

Video: Explosion Materials


 

Now we have all the elements of a sound as separate components we can also do other things with them, like spatialize them around the player in different ways. For the Game Audio Implementation book we built a simple system that will throw sounds around the player for people listening in 5.1 or 7.1. This could be used for elements of the explosion itself or for debris.

06_game_audio_Spatialized_Diagram

Figure 06 Diagram

 

07_game_audio_Spatialized_Detail

Figure 07 Detail

 

This was done in Unreal’s Blueprint system – which looks a bit daunting at first but once you get the hang of it you can pretty much do anything you might dream up!

08_game_audio_Blueprint

Figure 08 Blueprint

 

Video Thumbnail

Video: Explosion Spatialized


 
By using a procedural approach to sound design we now have an explosion sound that’s different each time, is ‘aware’ of the different materials involved in the explosion, and spatializes around the player in stereo, 5.1 or 7.1.
 

A big thanks to Richard Stevens for his insights on procedural game audio! If you want to know more about procedural sound design for games then check out the Game Audio Implementation book from Focal Press. If you’re new to UE4 you can get UE4 here for free, and you can download all the levels that go alongside the book here (also for free!) to get started.
 

Please share this:


 


 
 
THE WORLD’S EASIEST WAY TO GET INDEPENDENT SOUND EFFECTS:
 
A Sound Effect gives you easy access to an absolutely huge sound effects catalog
from a myriad of independent sound creators, all covered by one license agreement
- a few highlights:
  • Sci-Fi Dodge This Play Track 173 sounds included, 25 mins total $25 $5

    “..What are you trying to tell me? That I can dodge bullets?..” Neo, The Matrix.

    “Dodge This” is a set of sounds aimed to enhance “Slow Motion” and “Bullet Time” moments in movies, trailers and video games.

    It has a very strong Sci-fi feeling. So, If you need to create “passing by” bullets like in the famous “Bullet Time” scene in “The Matrix”, evoke big “Slow Motion” movements like the giant robots in “Transformers” or induce a state of focus in “Slow Motion” modes in video games, this library is great for you.

    Also you will find a nice selection of impacts with a a powerful time sensation that are perfect for trailers.

    Categories included:
    Atmospheric Element • Bass Drop • Dodge_Pass By_Movement • Fx_Movement_Bass • Fx_Movement_Sci-fi • Fx_Movement_Tremolo • Fx_Reverse • Hit_Impact • Hit_Low • Hit_Shot_Sci-fi

    Earn the power to control time!

    80 %
    OFF
    Add to cart
  • Animals & Creatures Animal Hyperrealism Vol I Play Track Over 1300 sounds included
    Rated 5.00 out of 5
    $170

    Animal Hyperrealism Vol I is a library containing sounds themed animal vocalisations, from real to designed creatures totaling more than 1300 individual sounds in 290 files.

    The sounds were partly recorded with animals trained for media production, partly recorded in zoos and wildlife centers. The asset list includes but is not limited to: african lions, bengal tigers, horses, donkeys, cows, exotic birds, owls, bobcats, pumas, dromedaries, wolves, dogs, geese, lemurs, gibbons and many more.

    All the content has been recorded at 192KHz with a Sanken CO100K plus a Sennheiser 8050 for center image and a couple of Sennheiser MKH8040 for stereo image. All files are delivered as stereo bounce of these for mics, though in some instances an additional couple of CO100K was added to the sides.

    The resulting ultrasonic spectrum is rich and allows for truly extreme manipulation of the content.

    Bonus: Two extra libraries included for free:
    This library also includes two additional releases from Mattia Cellotto - for free: Crunch Mode delivers 230 crunchy sounds made with a variety of vegetables, fresh bread, pizza crust and a selection of frozen goods. The Borax Experiment gets you 158 squishy, gory, slimy and gooey sounds.
    Add to cart
  • Footstep & Foley Sounds contains 511 high quality professionally recorded footstep sounds. Surfaces included: concrete, dirt, grass, gravel, metal, mud, water, wood, ice and snow. Plus 141 Foley sounds covering a variety of character movement sounds. A perfect addition to add realism to your footstep sounds.

    This pack also includes a variety of 160 bonus sounds effects from our full library Pro Sound Collection. ALL sounds from Footstep & Foley Sounds are included in Pro Sound Collection so if you need more sounds be sure to check it out before purchase.

    Add to cart
Explore the full, unique collection here
 
   
FOLLOW OR SUBSCRIBE FOR THE LATEST IN FANTASTIC SOUND:
 
                              
 
GET THE MUCH-LOVED A SOUND EFFECT NEWSLETTER:
 
The A Sound Effect newsletter gets you a wealth of exclusive stories and insights
+ free sounds with every issue:
 
Subscribe here for free SFX with every issue

3 thoughts on “Why Procedural Game Sound Design is so useful – demonstrated in the Unreal Engine

Leave a Reply

Your email address will not be published. Required fields are marked *