Behind the impressive sound of ‘Call of Duty: Warzone’

The Call of Duty franchise has stepped into the arena of Battle Royale free-to-play gaming with Call of Duty: Warzone. It offers fan-favorite weapons from Modern Warfare and an ever-expanding cache of new ones for the upcoming seasons. Plus, there’s an array of vehicles for traversing the map — something that’s new to the franchise.

Members of Infinity Ward‘s award-winning sound team, including Audio Director Stephen Miller, Principal Sound Designer Stuart Provine, and Senior Lead Technical Sound Designer Tim Stasica, and Source Sound Co-owner & Creative Director Charles Deenen discuss the different play modes in terms of sound, Modern Warfare asset sharing and modification for Warzone, designing and implementing dynamic vehicle systems, creating rewarding UI sounds, the challenges of mixing this massive game, and much more!

Call of Duty: Warzone – Official Trailer

Sonically, how does Plunder mode compare to Battle Royale mode? What were some of the challenges in designing sound for each play mode?

Stephen Miller (SM, Audio Director): The pace of the two game modes is what drives them sonically. At their core, the modes are the same – the weapons, Foley, vehicles, ambience – but all of the sounds and music supporting the modes is what enhances each experience. The challenge was approaching the design and implementation of sound and music accordingly. Plunder is “go-go-go, grab all the cash you can!!!” While Battle Royale is all about keeping your cool, as Captain Price would say, “Stay frosty.”

Audio Director Stephen Miller at Infinity Ward

In Plunder it is all about the action with arcade elements provided by big UI slams for all of the missions and mode changes. It also has more vehicles racing around you, with helicopters and jets screaming across the sky regularly. The music approach in Plunder is adrenaline focused with the score ramping up as teams frantically collect cash and get closer to the end goal. So it’s ok to have longer more intense music cues that kick in to drive that rush.

The approach in Battle Royale is different, it is about cautiously listening for enemies and distant skirmishes while trying to stay alive. Matches can get pretty sweaty as the gas approaches and you are down to only a few players left. We use music sparsely here to build on the tension the players feel in each moment. It’s also used as a useful warning to players that the gas is closing in and you’d better find a safe place to move. We let the game breathe much more in Battle Royale and focus on the subtleties. That space lets players get scared by the creaky wood roof or the metal pinging that might be someone nearby or just be the wind.

Were the weapons in Warzone pulled from Call of Duty: Modern Warfare only? Were you able to pull the gun assets from that game? What were some challenges in adapting those gun sounds to fit Warzone?

Stuart Provine (SP, Principal Sound Designer): The weapons in Warzone come from Modern Warfare.

However, during the course of Warzone‘s development it became clear that the distances involved in its much more immense playspace were going to require some changes.

Primarily, there’s greater audible range for the guns than we initially expected. Fortunately, we anticipated this scenario and recorded multiple perspectives of distant weapon fire during our shoots. Having the wide variety of source material on-hand made it possible for us to evolve the assets into what they needed to be to fit into Warzone.

Initially, none of the maps in Modern Warfare let players (or us) get far enough away to precisely know exactly what our most distant perspectives in Warzone were going to need sonically. So, at least in terms of asset creation, we’ve been trying to make the latest 3rd-person perspective sounds fit into the larger scope and scale of Warzone while also occasionally updating and refreshing previously made assets. We’ve also had to do a lot of mix tweaking to these distant sounds in order to accommodate the pace of gameplay and expanded player count in Warzone.

In addition to modifying the weapons from Modern Warfare, did you get to create any new weapons for Warzone?

SP: There is a symbiotic relationship between Modern Warfare and Warzone. New weapons continue to debut as the seasons are released. Our primary focus these days is creating the sounds for those upcoming weapons, and sometimes other things too in order to take a break from gunfire sounds.

That said, when a certain aspect of an older gun bothers us enough or if we notice a trend among player feedback that seems to warrant a revision, we will sometimes update sounds. We try to be mindful when considering these modifications as sudden changes can sometimes irk fans who liked how it sounded when the game shipped.

In general though, we’re creating new stuff that will appear in the future. The release of new content regularly prevents me from being as obsessive about it as I would be otherwise. A blessing in disguise, I’m sure.

What are some ways you used sound to quickly communicate important information to players? What are some sonic cues that players should listen for, to improve their survival rate?

Tim Stasica (TS, Senior Lead Audio Technical Design): So many sounds communicate useful game information to players, but here’s a few that are new and unique to Warzone.

• Players can now equip body armor, and when you shoot someone the hitmarker sound is different when you’re hitting armor vs. when it’s been depleted.

• We’ve added a ping system to aid in communicating with teammates, and each type of ping is unique. You’ll quickly know whether a teammate is pointing out pending enemies nearby, or whether they just think you should pick up that shotgun.

• The music in Battle Royale comes in just before the ring starts and stops moving – it can be a useful reminder of whether you need to move as well.

• The plunder chests hidden around the map have several layers of sound – these were a real challenge and went through many iterations. There is a layer that is only heard up close, and a layer that is not heard when below. Once you’re used to these details, you should be able to quickly tell if that chest is upstairs or not.

Can you tell me about your use of Foley in the game? What sounds did Foley cover? What is their priority in the mix?

TS: We lean heavily on Foley in Warzone. Despite the game being a completely dynamic, all player-controlled experience, we wanted it to feel gritty, real and cinematic. Part of that is using Foley not just for typical player movements but also on game actions – reviving a teammate, opening airdrop crates, calling in an extraction chopper – all of the sounds for player actions are Foley based even when there might not be an accompanying animation. This really helps the continuity of the soundscape, and it makes everything feel like a real tangible world.

The environment: How do the 5 sectors of the Verdansk map differ sonically? What are some unique sonic characteristics of each sector? How do the environmental sounds support gameplay?

TS: When we were working on the map, it was more granular than 5 sectors; there were more like 15 or 16 subsections of the map, plus the more sparse rural areas separately as well. Each of these subsections has their own ambient sounds and reverb. There will be more slap heard in the downtown area than in the open farmlands, for example. The top of the dam will have a lot more wind than the denser downtown area.

The challenge was in creating ambiences that add to the experience without inhibiting gameplay. There’s no distant airplanes or gunshots or any sounds that another player could make in the ambient sounds, but there are definitely wood creaks and pipe rattles that make players uneasy. We wanted to keep players on edge, but never fool them.

Is there real-time processing for reverb and EQ? How did you handle environmental reactions and proximity changes to match the sound of the space with what the player is doing/hearing?

TS: Yes, there is real-time reverb, delay, and EQ in game, and they work alongside asset changes depending on distance and environment. We run several real-time reverbs and delays to effect the player’s location as well as the locations of 3rd person players who are in different interior zones. We use EQs for LPF and HPF over distance, as well as differentiating interior spaces. But that is all polish on top of the assets. Our weapon reflection system plays different assets based on the player’s location, orientation, and the distance of the reflections, so every shot fired is a unique experience.

What went into creating the vehicles’ sounds and how they work in-game?

TS: Call of Duty traditionally isn’t a vehicle-based game. Vehicles are normally used for more cinematic moments, not exclusively dynamic. With the size of the map in Warzone, we knew players would be spending a lot of time in vehicles, and we had to implement a new vehicle system unlike anything Call of Duty has had before.

We worked with Adam Boyd at Red Pipe Sound Company and used Crankcase Audio’s REV middleware for the engine sounds. REV is an all-in-one solution for implementing dynamic vehicle engines into the game, rather than using less intuitive loops. Adam has a ton of first hand experience creating REV assets. We worked together to cast the vehicles, and he, along with John Fasal and Bryan Watkins of Warner Bros. Game Audio, recorded those assets.

Those assets and REV only covered the vehicle engine sounds. We also had to design and implement a system of sounds to cover the vehicles interacting with the world – actions such as impacts, suspension creaks, tire movement, braking, skidding, drifting for all of the vehicle types and surface types we have in Warzone. We worked with our amazing vehicle engineer, Manu Marin, on getting the playback parameters set up for the REV engines and additional vehicle sounds. It took a lot of trial and error to get vehicles feeling right, there’s no copy and pasting, every vehicle is a unique set of parameters.

The one exception to this workflow was the little bird, which was coded by Guillermo Garcia-Sampedro at Raven, and which a team of us from Infinity Ward recorded in California City in 2019.

What was your approach to creating the UI/UX sounds? And what were some tools that helped you in creating them?

SM: We worked closely with Charles Deenen and the incredible team at Source Sound on all of the UI. The original Modern Warfare series had always taken a hyped-up, raw, arcade-like approach to the UI. With the new Modern Warfare came a new approach and a new partnership. Stylistically, the UI needed to feel gritty, but still feel rewarding for big payoff moments.

Charles Deenen (CD, Co-owner & Creative Director at SourceSound): The approach we had for the main UI was to tell a story. We wanted to keep the sounds grounded to reality, by creating them from camera recorded items, dirty mics, etc. Then, offset those with clarity items (recorded radio beeps, etc.) and extend them with little snippets, which when put in random sequence could tell a bit of a story of the level and the feel of the game. This turned out to be a massive undertaking.

The rest of the payoff-type UI was built in a similar manner, but we added the usual size and a bit more of arcade-like feel to it. They play a lot and have to be recognizable, while not “hide” in the sound bed. I think there were over 400 of those types of sounds.

Was Warzone created using the same game engine as Modern Warfare? If so, how has your experience of creating Modern Warfare had an impact on your approach to Warzone?

TS: Yes, Warzone uses the same engine as Modern Warfare. This helped us in that we didn’t have to do any new experimentation or preproduction planning. We knew our tools, we knew what works and what doesn’t. But Warzone is its own monster; we’ve never shipped something this massive before. The memory challenge involved in having this many sounds for players, locations, vehicles, weapons, and game actions available to play at any given time was intense. We knew you had to hear sounds that are important to the player at a much greater distance than ever before, and that’s a mixing, asset creation, voice availability, and memory issue.

What were some of your challenges in mixing this game?

TS: The biggest mix issue is the sheer amount of sounds that can be playing at any given time, and the huge distance they can play from. You can’t just throw out distant sounds when you can be sniped from a half mile away. You can’t just throw out quiet sounds because you’ll lose the intimate grounded feel of the Foley interactions. There’s a lot going on all the time, and what’s fun is that it’s a live game. We’re constantly witnessing new gameplay that we’ve never seen before and reacting to it.

What’s the optimal playback system? Should players be using headphones?

TS: The best playback system… that’s an opinion that you can probably ask 10 people and get 10 answers. I prefer playing on a surround system. I can locate enemy positions much better in surround than on headphones.

The breathing in this game stresses me out!! Was that mixed to be intentionally present, to create this feeling of fight-or-flight?

TS: Of course the breathing should stress you out! Same as the creaking wood floors when you’re camping in an attic. The soundscape in Warzone is very dynamic, so when there’s not a loud A10 strafing by, there’s still a lot of sound happening to help immerse a player in the action.

Sound-wise, what do you love about this game?

TS: I love the addictive cash pickup sounds from Charles/SourceSound. I love the long spooldown of the Little Bird. I love the almost survival horror sound of the dam interior ambiences. I love the physics impacts of a ragdoll’d body sliding down a cliff. Of course, I love all of the weapon sounds that Stuart Provine has so expertly created. But what I love most is seeing all of our sounds and systems come together in such an immense, dynamic playspace to create a unique experience every time you play.

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