The Unreal Engine Audio Primer

The Unreal Engine Audio Primer by Dave Raybould

This will be my blog demonstrating the findings and demonstrations through Dave Raybould's 'How to quickly get started with game audio in Unreal Engine ' which you can find here. 

Importing Sounds

Let's start with importing sounds to the contents drawer. The file types supported by unreal are mono, stereo, 5.1 and ambisonic tracks, WAV files, AIFF, FLAC, OGG Vorbis - finally, the audio files that are imported can be any sample rate but they need to be a bit depth of 16bit. It is best to create a folder dedicated to the audio you import into the contents drawer. 

Area Loops

Area loops are the sounds that build up the overall background noise, like a room tone that produces partial sound to give the atmosphere a character to the level. They need to loop seamlessly. In my demo, I used a rain loop from the SONISS GDC library as an example. Once the sound is imported you double-click on it, and press looping - this makes sure that sound loops within the game. Once this is done, you can drag the imported audio file into the level, doing this creates an AmbientSound actor that references the file from the content browser. Forgot to mention, if you edit the original track and have an updated version of it; right-click on the file and press re-import - this updates the file to the current version.

Next is the attenuation settings, once the audio is dragged into the level you can go into the details window and enable 'Override Attenuation'. The settings can define the distance and the coverage of the sound in the level. 

(In this document, it details the various functions and usage of the attenuation parameters.)

Linear Attenuation: This is the default setting where the volume will attenuate in a constant motion as the listener/player moves closer or further away from the source sound. This is used for crossfading between large background sounds.

Logarithmic Attenuation: This attenuates a greater amount of volume at closer distances and lesser at further distances. This setting is great for sounds that require good 3D positioning.

Inverse Attenuation: This is the setting that is similar to a logarithmic curve when it comes to changes in the volume but on a more exaggerated scale. Good for use on sounds that need to be just heard from a far distance and louder when close to the source of the sound

Log Reverse: This setting is good for sounds that need to be heard across a large scale, the volume remains practically unchanged at close distances with volume changes occurring at further away distances.

Natural Sound: This attenuation setting is a model of the falloff behaviour that replicates real life sound.

Here is a little video I made giving a demonstration of the characteristics of the various functions. 

The other parameters for the attenuation distance that can be changed are the shape that determines the inner radius and falloff distance, there is a spherical-shaped, box-shaped, cone-shaped and capsule-shaped setting for this.

Here is a video that I made, there are two ambience tracks in the rooms that have been spatialized and not spatialized - In Raybould's article, he says that ambiences should not be spatialized to give the ambience its existence in that space. 

Source Loops

Source loops are sounds for objects in the level, for example, I did a demonstration of a static car model idling in the level. These sounds should be looped as they should fit the environment. In Raybould's article, he says mono sounds should be for smaller objects, or stereo sounds for larger objects to convey the space they are in.

Creating a sound attenuation asset makes it easier to have the same sort of attenuation setting across multiple objects.

One Shots 

To make a one-shot system, would require the use of Sound Cues and blueprints. In my demonstration video, I had some foley metal sounds that I put into a randomizer - this changes the order in which the sounds are played. A delay - this determines the time to the next sound. And finally, the loop which keeps the system repeating.

That's all I'm going to post for this at the minute as I want to go more in-depth with some of the topics in this great article. 

Stay Tuned!