Sound Design and Mixing Features for VR Games:

Counter Space Case Study

In this article, we'll discuss two main aspects of our work on the project: sound design features and the specifics of mixing for VR platforms.

About Counter Space Project

Counter Space is a VR multi-arena shooter developed by Gipnotech for their VR parks. The key feature of the project is that all players (from 2 to 24 people) are physically located in the same room, moving around with virtual reality headsets on.

The target audience is quite diverse - from children aged 7+ to adults with varying levels of gaming experience. A gaming session lasts up to 40 minutes but can be shorter depending on the individual player's tolerance for the VR experience. The target platform is Oculus Quest 2, and one of the important features of the project was the absence of strict limitations on the build size and audio data volume, which allowed our team to experiment with complex sound systems.

Sound Design

For developing the sound design of Counter Space, we used Call of Duty: Modern Warfare 3 as our main reference. We thoroughly analyzed the sound solutions of this game and identified several key aspects that we wanted to incorporate into our project:

Modern weapon sound design - Unlike Battlefield V, the sound in Modern Warfare 3 is more reminiscent of drum and bass: fast transients, rapid HDR, which works especially well with high rate-of-fire weapons, creating a distinct rhythm.

Fast informative mix - The player hears only what they need at any given moment.

Clear differences between interior and exterior shooting - Different sound signatures for shots depending on the environment.

Well-readable hit markers - Audio confirmation of hitting an opponent.

High-quality tracer sounds - Sounds of bullets flying by, creating a sense of danger.

UI sounds in the game's aesthetic

Differences in campaign and multiplayer mixes

Approach to Analysis and Sound Creation

At AK Audio, we believe that for a sound designer who wants to develop and create good sound, it's very important to play games. It's impossible to create something unique without studying both good and bad examples.

Our approach includes regularly exploring new game projects and analyzing their sound. For better understanding, we record gameplay and structure our observations (list of conducted analyses Telegram: Contact @aleksandrkhilko).

We also use the method of recreating sound systems from reference games. We believe this helps to gain a deeper understanding of sound creation principles. By recreating sound systems that we liked, we better understand how they are designed and how they were made.

Can you guess which is our game sound and which is Call of Duty Modern Warfare 3?

Creating Tracers and Other Sound Elements

We developed a detailed technical implementation of the tracer system - the sounds of bullets flying by. This system was created to generate a sense of danger for the player.

The basic principle of the system:

A conditional distance is established around the player
When a bullet (raycast) crosses this distance, a 3D sound emitter is created
The tracer sound can vary depending on the weapon type (sniper weapons create longer, more "dangerous" tracers)

During the project, we discussed the technical nuances of creating tracer sounds, particularly the possibility of using baked panorama in the sound instead of physically moving emitters for performance optimization.

Sound Positioning in VR

To ensure proper sound positioning in virtual space, we used a system of rooms and portals. We created a separate Unity project with boxes simulating the geometry of the game levels and set up sound portals in it.

Key features of the system:

Properly positioned colliders for rooms
Sound portal configuration for windows and openings
Transmission system setup for low-frequency sounds to penetrate walls
Various impulse response characteristics for different types of spaces (rooms, elevators, lobbies)

Occlusion and Diffraction

We paid special attention to configuring sound occlusion and diffraction systems. In our project, we implemented a comprehensive approach where sound is not simply blocked by obstacles but properly passes through or bends around them depending on the material and geometry.

For the occlusion system, we configured absorption coefficients for various surfaces and materials. For example, sound passing through concrete walls is significantly dampened, especially in high frequencies, while through glass surfaces a wider range of frequencies passes.

For sound diffraction, we set up a system that determines how sound bends around corners and passes through openings. The higher the diffraction coefficient, the stronger the filtering of high frequencies and other parameters are applied depending on the distance.

A particular challenge was finding the right balance between realistic sound propagation and gameplay requirements. In some cases, we sacrificed physical accuracy in favor of more informative sound, especially for sounds that are critically important for gameplay.

The most difficult part was ensuring that the farther the player is, the more accurately the danger from sound is conveyed. We needed to find a balance between realistic distance and gameplay informativeness.

For creating reverberation impulses, we used Altiverb, processing clicks from the Boom Library.

Mixing Features for VR

Sound in Oculus Quest

During our work, we noted that Oculus Quest speakers have quite acceptable quality for home use, with sufficient reproduction of low and high frequencies and good stereo field. However, in VR arena conditions, there's the problem of external environment noise (shopping mall music, people shouting), which requires a special approach to mixing.

Footsteps Specifics in VR

An interesting feature of working with sound in VR was the voicing of player footsteps. We concluded that in VR there is no need to voice the player's own footsteps. Since the player moves not with their feet but with a controller, synchronizing physical movements and footstep sounds is very difficult and creates cognitive dissonance.

However, the footsteps of NPCs and other players must be voiced.

Headphones vs. Headset Speakers

We paid special attention to the difference between using headphones and built-in headset speakers. Although using headphones provides better immersion, in VR arena conditions this creates safety problems. If all external sounds are muted, players will collide with each other.

In the future, we plan to solve this problem by adding a microphone and passing the voices of other players and coordinators through the system.

Distance Perception in VR

An important discovery for our team was that distance perception in VR differs significantly from perception on a regular monitor. For a long time, we were configuring sound for the Windows build. But when we tested it in a VR headset, we realized that in VR, due to a different angle of view, distance is perceived completely differently.

This required a complete reconfiguration of attenuations and occlusion systems specifically for VR.

HDR Mix and Dynamic Mix

To create a dynamic sound mix, we used the HDR (High Dynamic Range) system in Wwise, which is essentially an advanced sidechain system.

Dynamic Mix Off

Dynamic Mix On

Key HDR Mix Settings:

Very fast release for quick exit from deep sidechain
Sound prioritization: hit markers (+16 dB), player's weapon (+14 dB), tracers (+7 dB)
Lowest priority for background sounds (Ambient)

A feature of the setup was the creation of separate mix states for different listening methods:

For monitors/headphones
For Oculus Quest speakers
Considering external noise in the VR arena

The main task here is to convey the most important events in any conditions. It's important that the player clearly hears that they are shooting, that they are hitting, that they are being killed, or that they have left the boundaries of the room.

Conclusion

Working on the sound for the VR game Counter Space required non-standard approaches and solutions from the AK Audio team, taking into account the specifics of sound perception in virtual reality and the peculiarities of using the game in public spaces.

The key aspects we focused on in our work were proper sound positioning in virtual space, accounting for the difference in distance perception between VR and a regular screen, and creating a dynamic mix that provides informative sound in various listening conditions.

The experience gained while working on Counter Space can be useful for all sound engineers working with VR projects, especially those designed for use in public spaces like VR arenas.