Research: Audio in different spaces - Jelmerrr/DeepDive-SFX-Manipulation GitHub Wiki
2D vs. 3D audio
What are the differences between playing audio in 2D space vs. 3D space, when should you use which and how to implement them through FMOD?
When a barebones sound effect is played it is often like it is played exactly at your location. This is often referenced as a 2D event. The core principle of a 2D event is that the audio does not take distance into account when it is played. The sound effect is static no matter where in the world it is played or where the player is located. This means that whenever a 2D event is played, regardless of where the player or sound is coming from, it will always sound the same. A 3D event is when space and distance is taken in to account when playing a sound. Depending on the location of the player and the sound that is being played, it can have varying results. This means the player can get a more accurate judgement of where the sound is coming from. Usually in sound design both these type of events are combined to create the full sound scape but when should we use either one?
2D and consistent feedback
The biggest use case for 2D sound effects is when consistency and feedback are key. Since these sound effects are static, the player can be trained to link certain sounds to certain events happening in game. The player picks up a collectable and a happy ding plays. The player cycles through menu items and a soft whoosh sound is used to transition between two items. In all these cases the player does not really care where in the world the sound is played. Thus a conclusion can be made that 2D sound effects should be used for sounds that are non-immersive but important for feedback.
3D and spatial awareness
When 3D space gets included in sound effects there is a lot more depth that opens up. 3D soundscapes can be used to really immerse the player in the game and give a much more realistic sound. If something is happening to the left of the player, the player can notice the sounds actually coming from their left side and vice-versa. This gives the player a level of spatial awareness which helps both orientate the player but also keep the player immersed. 3D sound effects are often used to represent sounds that are dynamic and do not have a fixed position. Such as footsteps, a tree branch breaking or creepy ambient sounds.
Implementation
FMOD seperates 2D and 3D into their seperate events. A 2D event is relatively simple. Upon creation you can drag in the sound file desired, tweak it around untill it fits in the game and then assign it to a bank. When planning to create a 3D event however there will be a few additional things that you need to keep in mind.
In the Master Track of the event the spatializer will be added upon creating a 3D event. The spatializer is a way for FMOD to communicate with the game engine of choice what the details are related to distance and orientation. You can decide the intensity of the fading and also set specific limiters on orientation. Additionally you can also set the distance when audio should fall-off or be at its strongest.
In the game engine of choice you can then implement the sound effects through FMOD sound emitters. In this example the game engine Unity is used. For a more detailed overview of implementing FMOD events in Unity reference to the wiki page https://github.com/Jelmerrr/DeepDive-SFX-Manipulation/wiki/Documentation:-Adding-FMOD-events-in-Unity. Additionally for a 3D event you can see in-editor how big the distance of a sound will be. This helps give a good overview and idea of how it will sound like before actual testing.
Conclusion
In conclusion which type of event you use depends on the situation and the goal of the event. For events that are important for player feedback and UI it is recommended to use 2D events due to their consistency. For sound effects that are intended to be more immersive or require the player to know from which direction the sound came for 3D is the way to go. 3D events bring a level of immersion through dynamic audio panning based on the location and orientation of the player that is not possible to be replicated through 2D events.
Sources used for this article:
Mraz, R. (2023, May 4). The elements of video game audio - blog. Splice. https://splice.com/blog/elements-video-game-audio/
Authoring Events. Fmod.com. (n.d.). https://www.fmod.com/docs/2.01/studio/authoring-events.html
FMOD Advanced Topics - Spatialization Options. Fmod.com. (n.d.). https://www.fmod.com/docs/2.02/studio/advanced-topics.html#spatialization-options