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:  
  • We have created a small library to help with the ongoing need for safety videos during this strange time in our lives. From hand sanitizer’s to spray bottles, we have compiled a library to cover all forms of day to day sanitizing.

    20 %
    OFF
    Ends 1591394399
    Add to cart
  • Jump in a hot-off-the-assembly-line 2020 Porsche 911 “992” Carrera S from the comfort of your home or studio chair. This library won’t lose a cent of value when you drive it off the lot!

    Great for linear work or games – especially since it includes an easy-to-use Interior vs. Exterior mockup folded down to 2-channel files (ISO’s also included separately).

    This is our premiere foray into sound libraries here at Steamboat Sound, and we worked real hard to make it equally high-quality and easy-to-use – we hope you enjoy!

    Recordings include:

    Mockup channel order (panned, for easy editing in NLE):
    Channel 1 (left) – Exterior
    Channel 2 (right) – Interior

    Isolated tracks of all Exterior and Interior perspectives on idles, revs, engine starts & stops, various speeds, and more!

    Interior knobs, buttons, dials, seatbelts, sunroof, turn signals, buttons, windshield wipers, door open/close.

    Recorded with industry-standard equipment used on theatrical films and name-brand commercials, for your listening pleasure.

    40 %
    OFF
    Ends 1591307999
    Add to cart
  • MAGIC SOUND EFFECTS REDEFINED
     
    Enter the world of MAGIC – ARCANE FORCES, where supernatural entities can be heard raging with ultimate power and fury. The distinctly forceful and kinetic character of this comprehensive sound effects library and its designs is supported by countless pristine source recordings of the elements being pushed to their limits. Whether in post production or sound design for games, MAGIC – ARCANE FORCES gives you the edge on the other side.

    WHAT’S INSIDE:
    INCLUDED SOUNDS – KEYWORDS
    ACID, ARCANE, BARRIER, BREATH, BUFF, CURSED, DEBUFF, DIVINE, ELECTRIC, ENERGY, FIRE, GLASS, ICE, IMPACT, LIGHT, LIQUID, METAL, PROCESSED, PROJECTILE, RUMBLE, SEQUENCE, SUMMON, SWEETENER, SWISH, TELEPORT, TEXTURE, VOICE, WATER, WHOOSH, WIND
    20 %
    OFF
    Ends 1591999199
  • “The Shoe Collection: Soft Hardwood – Woman’s Knee-High Boot“ by Periscope Post & Audio, provides 22 high quality footsteps on soft hardwood floors with the knee-high boot.  The audio files are recorded at 24bit, 192k with mono and stereo recordings.  The Sennheiser MKH-60 was used for the mono files with a slightly more distant mic placement than the stereo files, which were recorded with the Sennheiser MKH8050 and the Sennheiser MKH-30 near the shoe.  From different walking speeds, to jogging, sprinting, jumping, hard stops, scuffs, and more!  There are several performances with each file to fit the right action you need.  That’s a whopping 620 footsteps between the mono and stereo files!

    17 %
    OFF
    Ends 1591135199
    Add to cart
  • Recording of the Pulse Jet Snowmobile. Powered by a 50 Hz Pulse ethanol/water jet engine the same used by a WW2 V-2 rocket.


    The Pulse Jet Snowmobile sound collection shares 28 clips of field recordings in 1.42 gigabytes of audio. Powered by a 50 Hz Pulse ethanol/water jet engine the same used by a WW2 V-2 rocket, this bundle presents the snowmobile racing at extreme speeds for a mix of perspectives.

    Both onboard and exterior perspectives are shared in two takes. The exterior perspectives arrange microphones at a mix of distances at the beginning, end, and middle of the racing strip. The onboard microphones were positioned onboard the body and at the jet engine to portray steady fast driving, with bonus custom mixes of the onboard and exhaust tracks.

    The sound library includes iXML, Soundminer, BWAV, and MacOS Finder embedded metadata, metadata keyword import files for 7 languages, and Pro Tools and Reaper mixing sessions.

    Add to cart


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:
  • Human Swordfighter Play Track 479 sounds included $25

    Swordfighter is a robust package with sharp sounding swords, heaps of variations and all the extras you need to make a fight come alive. Build unique sword swings with various hits, swooshes, schings, different fighter vocals and impacts on various surfaces. All up there are 137 sword sounds, 93 surface impact sounds, 15 knife throwing sounds, 48 swooshes and 180 fighter vocals.

    This version includes two sub-folders: one optimised for a film & TV workflow and the other optimised for video games workflow. Plus a few bonus sounds of a charging army.

    Add to cart
  • Alchemy of Guns is a comprehensive weapon laboratory of single sounds made to be mixed, assembled and fit with each other.
    We built the library as an array of modular layers, each one bound to a specific alchemical element, each one made with a specific Xfer Serum setup, and since we enjoyed finding ourselves sketching on paper combinations of elements according to the combinations of the samples, we kept this general structure.

    33 %
    OFF
    Ends 1591135199
    Add to cart
  • Genres Vintage Anime SFX Play Track 350+ sounds included $69

    The Vintage Anime Sound Effects Library brings all of the excitement of your favorite Japanese animated series to your fingertips. Inspired by classic cartoons from the 80’s and 90’s, these recognizable and versatile sounds will instantly enhance any FX collection. Vintage synths were used to create the auras, beams, mecha blasters, atmospheres, magic spells, guns, sonic blasts and explosives that makeup this pack of over 350+ custom 24bit/96khz .WAV files. Perfect for film, video games, podcasts and any project that could benefit from a power up!

    Both designed sounds and source recordings:
    • Classic anime sfx from the 80’s and 90’s

    • Auras, mecha, beams, blasters, spells, explosives and more! 350+ sounds!

    • Tons of source material for experimentation

    • Expert crafted metadata

    • Vintage Anime PDF

    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 *

HTML tags are not allowed.