War creates a glorious cacophony in the Call of Duty games. While the chest-thudding sounds of artillery, pinging ricochets of small arms, and desperate barks from your comrades help contribute to an intense sense of urgency, I’ll argue that one sound rises above all others as the ultimate call to action: an incoming hand grenade skittering on the ground, rolling toward your position. You only have seconds to react – either by grabbing it and issuing a battlefield return-to-sender, or moving away from its inevitable blast. It’s a critically important sound. During our trip to Sledgehammer’s offices for our Call of Duty: World War II cover story, I tracked down the person responsible for it. It may not be as explosive as other aspects of the game, but I’m hoping you walk away with a little more appreciation for one of the series’ unsung MVPs.

For a long time, incoming grenades were signaled with a strange-but-effective audio cue that Sledgehammer’s audio director, Dave Swenson, calls the “tink tink tink.” It didn’t really sound like an object bouncing around in the world, but play enough, and your brain would quickly associate it with “DANGER!” Swenson says that particular sound had been around since the beginning of the series. Swenson and his team had been pushing for higher-quality sounds since co-developing Modern Warfare 3 with Infinity Ward, and that work included reexamining legacy effects. “We were like, ‘Nope. That’s gotta go.’

“When you work on a franchise like this, there’s something you can easily do, which is, ‘Hey we have a lot of cool recordings, let’s just use those again.’” Technology and audio philosophies change over time, however, and Swenson says that he wanted the audio to be more dynamic with Call of Duty: World War II. It’s a similar approach that the team took with Advanced Warfare, but the dramatic change in setting meant they’d have to begin fresh with this new project. “It’s a fun problem to have, because we get to go out and make all new recordings, which I really enjoy.”

Swenson and his team are recording everything from scratch for their latest game. They’re doing their best to avoid traditional Foley recording in favor of getting audio on location, too. While stomping around in trays of gravel in a studio may be convenient, Swenson says that the resulting audio doesn’t sound as natural. And that leads us to Call of Duty: World War II’s grenades.

If you guessed that they got the sounds by throwing grenades and recording the sounds they make, well, you’re not far off. “We threw those grenades a million times, Swenson says. “They were all just beat up and destroyed by the end of it.” Obviously, recording live grenades to the point where they’re beat up is a horribly dangerous thing to do – even for a team that volunteered to get hit with actual flash-bang grenades during the development of Advanced Warfare. Instead, they used meticulously accurate replicas.

“For this game, primarily you have the American grenades and the German grenades, which are entirely different in their makeup,” Swenson says. The American grenades they’re using in the game are the pineapple-style ones, which are probably what most of us think about when someone says the word “grenade.” The German counterparts are often called “potato mashers” thanks to their design, in which the explosive payload is attached to the end of a wooden stick.

Swenson showed me one of the German grenades in his small studio space. “These are exact replicas, they’re built exactly like the German grenades. This of course would be filled with the explosive, so what we did is took car Bondo and packed it in there to give it the right weight.” The mechanism to activate these grenades is functionally similar to pulling a pin in an American grenade, but it’s definitely different: Soldiers would first unscrew a threaded cap at the end of the stick opposite the explosive. Once that’s off, a string with a marble at the end of it could be fished out. “That was the fuse, and they would pull that and that would start the fuse, and then they would toss it,” Swenson says. “So you would get this wood post with the explosive on the end with this little pigtail marble flying through the air, and it would hit the ground.”

As you can imagine, that string with the marble at the end makes a different sound than an American grenade. “The sound that you might be used to, it’ll be different because they were different. On the American side, the grenades are a little bit more of what we were used to recording.” 

Swenson says they have to record the sounds of grenades – both German and American – bouncing off several main surfaces: metal, wood, asphalt, dirt, gravel, grass, water, and carpet. Fortunately for him, there was a great location right by his house that allowed him to record several of those particular sounds while also getting in a little family bonding.

“I hadn’t seen my kids for a while so I took my boys with me and we went out just behind my house, and I wired them up with mics.” He shows me footage from the session, which he recorded on his phone. One of his young sons is holding a boom mic, and he tracks a grenade that his dad tosses from off camera like a pro. “We had this cool spot where we had this wood decking, grass, and then you’ll see over here, a thing of gravel and an asphalt road. All within 10 feet.”

Getting the right metal sound proved to be more of a challenge. Swenson thought he had it when he found a piece of metal over a culvert by his house, but it didn’t sound right for some reason. “I was walking back to my place and there was a manhole cover there,” he says. “It was like this really dense metal, and I tried it, and it was like, ‘Ah, that’s the sound we want!’ We had to have really good aim to get the grenade to land right on this manhole cover, but out of all the places we tried, that’s the metal hit I wanted. It’s just a matter of finding the right moments.”

Once the recording is finished, Swenson and his team clean up the recordings and make minor tweaks to ensure that they communicate the all-important “Grenade!” cue to players. “What we’re looking for is for the player is to go, ‘Oh, that’s the thing!’ 

“The grenades, we accentuate the bit of rattle, and it’s probably a bit more than they would actually have. We do that because we’re trying to make an identifiable sound that’s super unique, and you won’t hear it anywhere else in the game – except for that moment where you need to hear it. We want to cause that ‘Ungh!’ feeling for the player. When a grenade hits, we’ll duck the mix back and make sure it pops out of the mix so you hear that asset, because it’s important communication to the player.”

Look, I get it. Grenade-rolling sounds are not sexy. Even Swenson acted genuinely confused when I had to clarify that I wasn’t interested in talking about the grenades exploding, but the part before. With any luck, you’ll give that sound a little more thought the next time you hear a grenade bounce into your bunker. After it’s safe, of course.

 

We'll have more exclusive reveals, videos, and information on Call of Duty: WWII throughout the month, so be sure to check out the coverage hub.