How ‘Call of Duty: WWII’ Shrunk Its Audio Production for a Bigger Sound

Jeremy Ray
Games PlayStation
Games PlayStation Call of Duty Xbox PC Gaming

When we think of the Call of Duty series, we think of high production values. Certainly in our Call of Duty: WWII review, we felt the sights and sounds of its iconic WWII battles were its most impressive features. Tired as we are of the setting, it deserves credit for fantastic cutscenes and set pieces.

Sledgehammer has routinely delivered quality games. Say what you want about Call of Duty’s business models and repetitive story twists, but you can’t reasonably accuse the franchise of ever skimping on graphics and sound.

So it might surprise you to hear the audio budget on Call of Duty: WWII was actually miniscule compared to previous games in the franchise. Sledgehammer still had access to a professional studio and gear, but wanted to capture the “indie” feel of making audio on the cheap. Far from “skimping,” this was less about saving money – there was always a safety net, being Sledgehammer – and more about innovation.

David Swenson GDC Call of Duty WWII audio talk
David Swenson talks to a GDC room about CoD WWII's unique audio development.

It’s hard to be a hungry millionaire, as they say. Access to the latest mixing decks and sample libraries may actually cause an audio designer to bypass that age-old process of problem solving. It’s a situation that could lead projects to sound like every other triple-A game out there. With Call of Duty; WWII, Sledgehammer wanted to force itself to come up with creative solutions.

David Swenson is the audio director at Sledgehammer Games, and told a room full of professional audio designers at this year’s Game Developers’ Conference how his team made triple-A audio for a fraction of the cost. It involved getting their hands dirty… but it sounded like a lot of fun.

There’s a Boom in Shot

The no-frills approach to audio design involves spraying water on leather jackets, crawling in the mud, running on the beach, pouring water onto rocks in the backyard, and much more. That covered the basic sounds, but for the larger things like specific plane engines, the team would have to get creative.

According to David Swenson, there were several benefits to this approach:

  • When something didn’t work out, there was the ability to have a do-over
  • No big, expensive shoots where everything hinges on one day
  • It encouraged a start-up mentality

For recording gunshots and tails, the team went to an empty area and set up mics everywhere it could. It turned out the audio sounded terrible on every mic except the one behind the car. In this smaller operation, it was an easy logistical task to get back out there and re-record everything with every mic in that sweet spot.

Getting the sounds of a particular plane as it came down was proving to be a challenge, as the team wasn’t allowed to stand on a runway. A trip to Google Maps revealed that there happened to be a golf course adjacent to an airfield nearby, with – lo and behold – one hole conveniently placed right next to the runway. The team actually snuck mics inside disguised as golf clubs (see image below) to hang out near the runway and record planes coming in.

GDC Call of Duty WWII slide
Sledgehammer forced itself to find clever solutions.

Google Maps was often used when the team needed to find a suitable area to record. Purely from browsing the service, they found an abandoned mall with a bunch of junk inside. Throwing those items off balconies and into walls formed much of the sounds of destroyed rubble in CoD: WWII.

It didn’t stop there. Even after the recording period, Sledgehammer wanted to avoid the ways of a massive studio and adopt a lean, flexible, start-up mentality.

Post-Processing Pros

Early on, the decision was made to let every sound designer use whatever program and plugins they wanted. This increased sharing of ideas and diversified the team’s audio — but it also meant many designers couldn’t share sessions across the same program.

There wasn’t a separate, final audio program to aggregate everything into. According to Swenson, the “final audio program was the game.”

These sound designers would implement everything into the actual level. They had a proprietary scripting language they had to learn, which meant doing a little bit of coding. Armed with that, they’d be able to perform the usual role of audio level designers. They would own a sound all throughout the process, from the boom to the room.

Call of Duty: WWII uses High Dynamic Range audio to focus on dynamics over raw loudness. Swenson stressed that there needed to be a clean and focused mix for a more cinematic feel. “We needed to avoid the Wall of Sound trap,” he said.

In some cases, that actually meant completely cutting out some of that audio they had painstakingly recorded. In chaotic scenes like the D-Day landing, there’s so much happening that they had to ensure the player heard what was important.

With large teams in multiple locations, this meant being very clear to everyone about what sounds were prioritised, and what was not to be touched.

“We had to have rules to prevent the instant gratification trap,” said Swenson, “where a sound designer makes their one small thing very big and loud. Guns were always the star. Explosions are big. Other things would take a backseat to that, and we’d reduce the db if they don’t fall into the star category.”

One of the benefits of working on a major franchise that three studios contribute to is the sharing of assets, but the move to High Dynamic Range sound limited what Sledgehammer could implement. When combined with HDR sounds, the older assets would break the immersion. The last few games being more futuristic also limited how much they could grab.

Swenson also knew that due to the immense wall of gunfire that would occur at certain points in the game, the soundtrack should be free of percussion — while still being orchestral to sound cinematic. There would be no drums to drown out the guns, and instead of sound effects, different musical instruments would be used in stealth sections to communicate stealth ideas like being noticed.

Life as a Sledgehammer Sound Designer

Every sound designer gets a kit when they start at Sledgehammer, and they’re told to keep it with them at all times to record the smaller things in life. It enables them to focus more on the debris — what explosions do to the world, as opposed to the explosions themselves.

The team needed tree bursts, for example, for when the Germans would hammer a forest with artillery. Seeing as every employee is also given a sledgehammer when they start their job, they took a sledgehammer to nearby trees.

“We’re hung up on being as literal as possible,” said Swenson. “We went to a river to record a river. We went to a bunker to record a bunker. We used the real old weapons.”

In that same vein, the team wanted to record the exact tank that would be included in the game. After recording a friend’s (yes, a friend with a fleet of tanks), they found the engine was way too loud to hear anything else. They wanted the treads, the engines, and the metal groans.

After browsing Youtube, they were able to find a tank owner running the engine in isolation. They zoomed in on the owner’s nametag and chased down his contact details. He thought Sledgehammer was trolling him at first, but agreed to have them come record the engine at different RPMs. They then manipulated an air vent for an hour for the sound of metal groans.

After showing several frugal techniques for recording sounds of destruction, such as breaking wonderboard to emulate cement cracking, putting a subwoofer up to a medical cabinet for vibrations, and lots of plugins, Swenson was able to show us the result: a massive belltower collapsing. It’s a sequence anyone who’s played the game will remember, and it only adds to the moment to know the unique process that created it.

One hour later, Swenson had shown his work and proven his claim. His message to all the audio designers in the crowd was simple: “Anybody can buy some wood and stuff from Home Depot, and create the same thing.”

Jeremy Ray
Managing Editor at FANDOM. Decade-long games critic and esports aficionado. Started in competitive Counter-Strike, then moved into broadcast, online, print and interpretative pantomime. You merely adopted the lag. I was born in it.
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