
One of the biggest new engine enhancements we made for Call of Duty: World at War was to the Audio engine.
When it came to audio engine modification, our Audio Director, Brian Tuey, led the charge, which is why I asked him to share his thoughts about what’s new in Call of Duty: World at War from an audio perspective. I personally found it extremely informative, and hope it explains some of our innovations a bit more clearly!
Audio Technology
The Call of Duty franchise has always been about great gameplay, great graphics, great design…and great audio. One of the reasons why the franchise sounds so good is because it strives for ultimate authenticity. From its full musical scores to weapons shoots to capture the sounds of authentic weapons of the era, Call of Duty has always been on the forefront of what you can do with audio.
Call of Duty: World at War is no different. Given the amount of processing power that we have on the newer platforms, we knew we could do some new things with sound to deepen the player’s experience and really bring our levels to life.
We are now doing a lot more than just recording a sound in the field and playing it back on your console (or PC) when an event happens. We now have to think about the context where a sound is played and what kinds of things we need to do in the game engine to more accurately simulate real life so we can deepen the players experience and really bring our game to life.
Two important pieces of new technology for World at War are Occlusion and Flux.
Occlusion
So what IS occlusion? It's the concept that if a sound has to travel through an object, its going to sound different than if the sound plays with a clear line of sight. If you imagine someone yelling at you and you slam the door in their face, their voice would sound significantly more muffled through the closed door than the open door.

Note: Screenshots taken in development environment.