After our collaboration with DICE, which was recording the explosion sounds for Battlefield V and our latest release: Urban Explosions – Bence Pajor (Audio Director Battlefield V), Andreas Almström (Lead Sound Designer), Ben Minto (Studio Audio Director) from DICE and BOOM Library’s Axel Rohrbach (Creative Director) are on hand to answer our questions about this project. Find out everything about the recording session from preparation to result, why it is very important to have an experienced blaster on-site and learn more about the final sound in the game and our latest product. Have fun reading!
The biggest German news website „Spiegel Online“ wrote a very positive review about BFV. They wrote for example: „Hardly anything in “Battlefield V” is as impressive as the sound.“ What was your approach for the overall sound?
“Our overall approach was, as always, to make something that is extremely immersive, realistic and frightening. We have always built the Battlefield games on as much of our own field recordings as humanly possible. This in order to have as much control over the source material as we possibly can. We want to experience and capture all the sounds in real environments similar to the ones in the game. Not only does this give us a chance to author exactly the sounds we want, but it also gives us a reference and a reminder of how they feel.
Anyway, up until now we had never recorded proper, real explosions ourselves. So the idea for this recording was born when we met with Axel Rohrbach (BOOM Library) in San Francisco a couple of years ago at a huge, yearly conference called GDC, Game Developers Conference. We thought that it would be awesome to do a joint recording session sometime somewhere and record something… interesting yet useful. After some discussion we came to the obvious conclusion that explosions with military grade explosives in multiple controlled environments at various distances was the only thing that we hadn’t really recorded before.
And to our incredible joy and satisfaction, BOOM made it happen, at an old Soviet military base!”
Can you give us a short summary of what exactly detonates within the BATTLEFIELD V? If the list of things that do NOT detonate will be shorter, we’d still take the first list 😉
“We have everything from 20 mm incendiary bullets to 1000 kg bombs. And that includes air bursting small and medium caliber anti aircraft rounds, hand grenades of different types such as impact grenades/Mills bomb/Stielhandgranate 39, Dynamite, Anti tank bundle grenades (Geballte ladung), Springminen and anti tank mines. Tank shells ranging from 37mm 95mm, a massive 380 mm rocket propelled 376 kg round that is shot from the menacing Sturmtiger. We have mine clearing line charges (google MICLIC, it’s fun!). Dumbfire rockets fired from both airplanes and armored cars, unguided bombs ranging from 50 kg to 1000 kg, including the impressive 850 kg warhead of the sonically iconic V1 rocket.”
What can we expect from the BOOM LIBRARY URBAN EXPLOSIONS library? Which sounds / sound range?
“When you think about where Explosions in media mostly happen, it is in urban environments. But there are not many source recordings of urban explosions, obviously for a reason: it is not very easy to record, you can not simply visit a city and record there. On the other hand, one building is not enough, there have to be several buildings to get the distinct echoes, they should be rather big and set similar to a street. At the same time we were looking for recordings that are flexible enough to be used in non-urban environments as well. So the range of sounds is CLOSE to FAR recorded explosions, with very distinct to very open echoing.”
How is the creation of a sound FX library that was recorded for a AAA game different than the creation of a „regular“ BOOM Library?
“It actually is not very different. We always try to improve our work and do our best to create the highest quality we can. That is obviously not different to any production that has a specific title in mind. We want our products to be usable for any kind of triple AAA titles, be it games, movies, shows and so forth.”
How was the collaboration with the BOOM Library team? What did you like most about working with BOOM?
“BOOM Libraries are first and foremost very professional in how they work. Planning, equipment and dedication to making sure to capture everything in as high fidelity as possible really sets them in the very top of the spectrum. Also, they are really lovely people to work with!”
You have worked with explosives before; which previous experiences came in handy this time?
“We did record different types of explosives before, so we had some experience on this topic. The slower the burning time, the less loud the initial transients are. However, we needed some loud bangs to trigger these nice tails, that is what we were after, less a quick burning sound like you get with fuel bombs and similar explosions. So one thing we knew in advance: we need something loud. The bad thing here is: it doesn’t look very cool, you won’t get this huge fire balls you know from the movies. So for cool videos and marketing material we probably should have done one typical movie explosion anyway. As with gunshots, the same counts for explosions: the most important thing is the environment, so we planned some spotting hours on site to find the right spots to record.”
How are urban explosions different from explosions in a plain field? How did you choose the explosion sites?
“Urban explosions in contrast to explosions on a field has very distinct early and late reflections that gives the initial impulse its identity, essentially the fingerprint. That makes us understand what kind of environment the sound is resonating in. Fields does have early and late reflections, but they are less distinct since the amount of hard surfaces they reflect against cant compare, and it’s that combination of soft and hard reflections that gives the listener audial information on the surroundings.
For us it’s important to represent as many of these different distinct environment types as possible, be it urban, fields, forests, different indoor environment etc. to match what environment the player is being in. This also collates with the overall soundscape where the environmental is reflected in all sounds that have a high SPL, be it guns, cannons or explosions, they all have to resonate together in a believable way.
On site during the recordings we choose a few distinct locations, between buildings, on the outskirts, on fields, and indoors. This to be able to mix and match recordings as true to what the ingame sounds needed to be.”
What was there to consider in the run-up to such an extraordinary session? What had to be planned?
“First of all we had to find a very communicative, open minded expert blaster. Doing such recordings is a bit different to what blasters normally do: when they do explosions for movies, they want it to be as quiet as possible with as much visual effect as possible. If they are in the demolishing business they also try to keep it quiet but effective. We needed quick preparations for a lot of bangs, it didn’t matter how they will look or what they actually will do to the surroundings, but they should have a strong and loud bang.
So the blaster had to leave his comfort zone. The second important thing to do is to find a place and a time. We were really after something very hard to come by: a super quiet area with as many buildings as possible without any populated surroundings to avoid the noise of street traffic, people, fieldwork or whatever. It needed to be officially accessible as recording explosions over three days at that sound pressure is definitely something you will hear from miles away, so there was no way of not having this officially approved.
After we found the right place, official licenses and agreements had to be applied for. This can take a while though. It has to be carefully scheduled with some time ahead, so that the location is available at the planned time, the licenses are signed in time and everyone else involved is available. When this was done, the blaster needed to apply for licenses to drive around with a car full of explosives. In this case he had to cross two borders, so this was something rather sensitive. Only when all this was done, flights, rental cars, rooms etc had to be booked. So this was quite an undertaking.”
How many microphones did you bring in total and how many channels do you deliver per sound in the library?
“With five recordists at different spots per explosion we had a maximum of 26 microphones (some of them were stereo microphones + one four channel ambisonic microphone) and up to 42 channels. There were some experimental setups and handhelds that were placed at weird places. Luckily we think that all of these turned out to give something special and unique to the whole set.”
Roughly, how many hours did you spend recording the urban explosions?
“The pure time in the field would be around 20 hours over three days plus the day before doing some spotting of the surroundings. It’s not that we recorded 20 hours of audio, a lot of time is being used for setting up the microphones, moving to different spots etc. One explosion doesn’t take that long, so once set up, this is most likely the smallest part concerning time.”
What was the closest and farthest distance to the blast you managed to record?
“We did some sound checks and had to move further and further away at the very beginning, even with dynamic or very high pressure condenser microphones. So the closest in the end is 4 meters, the farthest 200 meters.”
Couldn’t you simply use impulse responses to simulate real urban explosions?
“Impulse responses (IRs hereafter) is an area that we haven’t dug completely into, but we use it for voices and an overall glue to our recorded content. IRs are essentially a fingerprint from one sound source to a microphone during one point in time, and no matter what content you send into the IR the early and late reflections are going to behave in the same manner in time, and that collides with our overall vision of having as little repetition as possible. On site, one recording to the other is going to have more factors than just the location impacting the resulting reflections, such as wind, humidity and slight offset and detonation velocity of the explosives placed.”
Did you need any special equipment other than recording gear (e.g. for communicating over long distances)?
“No. In fact that might be useful for the future, however we were very confident with each other and simply had a very good communication before we started to record one specific spot and right after. Some things we always bring to these longer field days: duct-tape, a lot of trash bags for rain covers (heavily needed this time), some towels and cloths to be able to cleanup some things. Obviously snacks and water to keep us hydrated and concentrated plus sun protection. Unfortunately, I forgot my rain-suit, so I had to borrow a nice yellow XXL coat from our blaster.”
Apart from the ground, what else did you attach explosives to?
“We threw bundles of explosives into a small artificial lake to get the mouth opening rumble of explosives under water, with resulting spray of water afterwards. We also attached a fairly big bundle of plastic explosives to a small tree to get it off the ground in order to get a clear line of sight/sound to it, since we decided not to be too close to it. The tree disappeared, and fortunately no sound designers were hurt :-)”
Did you run into any issues (weather, birds.) or other challenges (e.g. soldiers)?
“Uh yes, several actually. Concerning birds, there were no issues. We were actually kind of surprised and a little bit worried, because there were only very few birds and insects around. However we recorded in September, so not the most busy bird season. During the second day it rained for 5 minutes every hour. So every hour we had to jump up, grab the trash-bags and pull them over the mics, the recorders and cover any sensitive cable connections. And we had to put on and take off rain jackets over and over again. When there was no rain the sun was shining and it was pretty warm. You could say that it was a bit hectic now and then. On the third day we initially wanted to record more explosions outdoors but it was pouring rain the whole day. We almost dumped the car with the explosives in a deep puddle that wasn’t there on the day before. So we decided to do indoor recordings instead, which actually also is extremely rare and we are super happy the weather forced us to do these recordings.”
Were there any dangerous situations during the recording session?
“We recorded on a military compound and even though we thought the whole area would be reserved for us, the military decided to do some camouflage training at the same time. We talked to them and it turned out to be no issue: they trained to be silent and unseen and they just told us in case we would see someone, we should simply ignore them. But at one spot we placed explosives around 5 meters in front of a building entrance. After our blaster shouted “fire in the whole” to tell us, that the explosive is live and we should hit record a soldier just stepped out of this very door. So we started shouting and waving, trying to get the guy out of the area. Nothing happened, our blaster is very professional and vigilant so obviously we were able to hold off until the guy was gone. Still, they were aware what we are doing and for sure hearing it all day long. So this was a weird situation.”
Did all the gear make it back home in one piece?
“Yes. We had no issues but we were also well prepared and we always try to clean up whenever there is time or to dry stuff right away when it got wet. Also we know our microphones pretty well, so they were all set up in distances we knew would work well for each mic.”
Are you satisfied with the in-game explosion sounds?
“Yes, we are very happy with the result. This is the first Battlefield game where we actually were part of making the source for the environmental layers of our explosions, and that really sets it apart from our previous titles. Our explosions are composed ingame from many layers that describes proximity, environment, and velocity. While all layers are important, the BOOM recordings gave us a completely new and real flavour to the environmental layers.”
How big is the impact of the recording session on the overall Battlefield V sonic experience?
“For Battlefield there are so many things that is a threat to the player, be it a burst of distant crackling bullets from an MG42, a JU-87 Stuka screaming towards you or a massive Argus AS 014 propelled bomb folding the earth around you. Getting all these threats to stay in the same world and not be its isolated sound design peace we have to have the best source we can get and this session did just that. We take much pride in recording as much as possible because it allows us to make choices on location and experiment with microphone placement to fit our needs in the game. This explosion session was a key puzzle piece for this project, since it helped us further reinforce our overall direction of a realistic and immersive soundscape. Nothing sounds more real than the real thing :-)”
Who would you recommend the library to? Which scenes can be set to sound?
“So first of all obviously for anything that explodes. Not only in urban environments, the material is pretty flexible to use. The sound of explosions however can be used for a variety of use-cases. A rather obvious usage would be to use them to pimp up similar physical events like gunshots, ignitions of epic engines, canons. However, explosions can work as sweeteners for a huge variety of applications. That could be footsteps of creatures like dinosaurs, dragons or door-slams. You can use it for impacts that do not really explode like rock cracks, car crashes or as sweetener of pass bys – not only on spaceships, but also even on cars if you want to really accentuate that moment. So this is a pool of very cool sources, it is your choice how to actually make use of these.”
How was working with the DICE audio team?
“The DICE audio team is an extremely experienced team with a good idea of how to work in the field and what they want to achieve. So from our point of view: it was exactly like doing it with friends: we briefly discussed what to expect from each other and then worked hand-in-hand as if we would have done tons of recordings together before. Very smooth, very easy going – or to put it in other words, highly professional.”
Would (or will) you use these explosion sounds in other DICE games, such as Star Wars Battlefront?