6 urban locations, 3 automatic weapons, nearly 2 years, and many talented people: Pole Position Production is delighted to finally release The Urban Gun Acoustics sound effects library.
I spoke to co-owners Max Lachmann and Mats Lundgren about how the project began, its obstacles, and how Pole overcame the challenges to record over 600 gunshot sounds with characteristic tails.
Max, Can you tell me a bit about how the Urban Gun Acoustics Library began?
Max Lachmann: As we are doing more and more weapon sound design for various game projects, such as for Arena Breakout Infinite and many more, we have realised how important it is to not only have good source of the actual weapons, but also of the tails and echoes of the shots. It’s the tails that tell the story of where the weapon is being fired, in which context and distance. Since source material of this kind is quite rare, we have recorded a few libraries with both indoor and outdoor tails. So when our friends at Embark reached out and asked if we were interested in doing a recording in an urban environment together with them, it was a no-brainer. Good recording opportunities with nice people, what else can you ask for?
Shooting weapons in environments like factories, quarries, and halls give gunshots a specific sound. What effect were you looking for with these recordings?
Firing weapons in different environments give them a very special character. A field and a forest for instance, have their specific sound, somewhat similar to what you can expect from a very good reverb. But weapons fired in an urban environment have a much more complex tail, with slaps and bouncing across the area. And it gets even more complex at a distance with all the obstruction and occlusion that adds to the sound. It’s an acoustic phenomena that is very difficult to recreate, so good source material is very helpful here.
Finding places with the sonic character you needed isn’t easy. How did you track down the locations you used?
We did quite a search to find a good location. There are places with abandoned smaller house areas, hotels and so on. But they are often just a few buildings, and where wildlife has taken over with birds and other disturbances. We looked at a few training areas for military and rescue personnel, but they were mostly mock up buildings made of wood and with plastic windows etc, not offering the characteristics we were hoping to get. Eventually the Embark people suggested a partly abandoned concrete factory. We had seen the place before in music videos, and also tried to get access before, but not managed. Somehow Embark managed to get permission to use the place which was really nice.
The weapons you used (AK 4, Kpist m/45, Ksp m/36) are all quite distinctive: a battle rifle, a submachine gun, and a heavy machine gun. How were you able to find these weapons?
The weapons were selected in order to get a good variation in the sound, so based on caliber and type of weapon. We are lucky to have a good relationship with an armorer in Sweden, Anders Lexne and his staff, who is actually the only private company in Sweden who have the licenses needed to fire automatic weapons. It’s very helpful to work with the same people every time, since they know the drill about keeping quiet while the tails fades out and so on.
Recording guns is a challenging task – they’re incredibly loud and also dangerous. Capturing the character of such large and unusual spaces can be quite tricky, too. What was Pole’s plan for getting the job done?
The main attack plan on a session like this is to try and have microphones everywhere. You never know what will sound good beforehand, so we rig microphones close up to the firing position, and then on different distances and spots around. It can be inside a building while the weapon is being fired outdoor to get an interesting resonance, or behind a concrete wall and so on. It’s complex for many reasons. The distances make communication difficult, when we are about to start firing and when everybody needs to keep still and quiet. And sometimes you can have a disturbing noise or wind at one spot, which is more sensible if being far away from the source of the sound. But this is a calculated risk, that is why you want to have as many sets of microphones as possible around the area. You might not even care to edit a few of them once back in the studio, if they are too polluted with unwanted noise. Another challenge is that you need to be quite a team on location to cover the area, to run in between all recorders is simply too time consuming. Remember, we are trying to do six different firing spots during the day, that might mean also some of the exterior rigs have to be moved around for each firing spot, not only the close up rigs.
Can you tell us a bit about the equipment you used? Were there any microphones or audio recorders that “stole the show” during the session?
Obviously, using 32-bit recording is very helpful for the close ups on a stressful day on location. It means you have more work to do when you get back home, but at least you know that the material will be useful. Levels are not as much of a problem at a distance as long as you monitor the first shots being fired.
For all tracks that are intended to be used as tails, a stereo perspective is nice to have, so stereo rigs or microphones are preferable. While the microphones set up to get the actual weapon being fired, it might as well be mono microphones.
For the close microphones, we used the high-SPL DPA 4062 on the gun itself and a Sennheiser MKH 8060 above and below the shooter a meter away. Many of our medium distant perspectives featured a selection of stereo microphones. Our primary stereo microphones included a Sanken CSS-5, a Neumann RMS 191 in MS, a Sennheiser MKH 418-S, also in MS, and a Sennheiser MKH 8040 in ORTF. Many other microphones from LOM, Line Audio, and Zoom were used.
As I had mentioned, the shoot called for as many 32-bit recorders as possible. Some recorders we used were the Sound Devices MixPre-10 II and Zoom F6, as well as some of our favorite 24-bit classics such as the Sonosax SX-R4+, and many others.
The session took a lot of time and planning to set up. Can you tell us how things went when things were rolling?
It’s been a while now, but as I remember it the session went very smooth and was greatly planned by Embark and us. We had discussed beforehand what equipment we would bring, and had a rough idea of what should go where. Embark had prepared snacks and drinks, which is crucial to keep a big team in a good mood for a long and stressful day. It also helps to know that you are being part of a very rare occasion and session, it somehow makes you focus that little extra, but it also helps to keep your mood up.
Mats, you were in charge of editing and mastering the recordings. When Pole returned to the studio, the team had an immense amount of material. How did you get started editing the sounds?
Mats Lundgren: The amount of material that the boys came back with was absolutely massive. They had managed to record at no less than six different locations in one day, of which four had an enormous amount of microphones. To be able to keep track of everything we made a chart with everything listed: recorders, microphones and their respective stereo patterns, distance and position in relation to the shooter and whatever additional information there was. Additional information could be for example if the mic was attached to a specific object, or if it was behind a container; anything relevant that gave a clearer picture of the location and that later could later be put in the metadata for each track. All this information was then put into each track’s comment section in Pro Tools.
One thing that made this procedure more important was the fact that the area covered for the session was really large, and that not every microphone was moved for each new shooting location. That meant that on one location a mic position could be fairly close to the shooter, while on another the same mic position could be very far away, with completely different slapbacks and noise to signal ratios as a result. Needless to say wind and related problems became much more evident the longer from the shooter the microphone was located.
In all there were up to 25 microphone positions resulting in 47 channels of audio, mono, stereo and Ambisonic. So the first mission was to line up all tracks, then start to get an overview of each location, trim down the amount of silence between takes, and step by step getting the material to a state where it could be handled with at least some ease.
Recording weapons on location is difficult. Editing the material has its own challenges. Can you tell us a bit about the issues you found with the recordings?
In a perfect world you would pick and choose days to record when there is no wind or other disturbing weather conditions, no birds, no traffic and no airplanes passing over. Everything would be just quiet and serene, with not a hint of disturbance polluting the recordings. In reality that is of course hardly ever the case and we must always try to avoid such things as much as we can, using windshields, hiding behind walls, sometimes waiting for the weather to improve. But you can only do so much.
The day for the Urban Shoot Session was at times really windy, with some rain and drizzle. On top of that there were plenty of birds, on one occasion there was even a car that turned up and played some radio into the microphones for a little while. So there were lots to deal with when it came to cleaning the session from all that was going on.
And how did you tackle those problems?
Getting rid of unwanted noise is not that hard. Getting rid of noise without anyone noticing it on the other hand, that’s very hard. The biggest challenge with cleaning the Urban Shoot Acoustics session was to get rid of all the wind and other noise, while keeping the tails of the guns ringing out as long and unaffected as possible.
There are a number of tools that we have at our disposal, the most important and specialized being Izotope RX. RX is an excellent tool when it comes to editing out very specific sounds, like birds or other noise that you can pinpoint. There is however a risk that if you affect too big portions of the sound, like really strong high-frequency wind noise, it can leave rather big unwanted artifacts to the sound. So for cleaning out high frequency white noise caused by wind I relied instead heavily on the F6 filter by Waves Audio.
F6 is a dynamic filter that allows setting a threshold for the filter to open, with an attack and release time. Using this I could dial in filter values that open on attack (i.e. the gunblast) so that the echo of the shot bouncing around the area gets preserved, but when the white noise becomes evident the filter closes. Using this method I could get rid of a majority of the noise, even on the most affected tracks with microphones at a distance of over a hundred meters.
However, the downside of using this method is that if you aren’t careful you run the risk of getting a sweeping filter effect. This might sound cool in a dance music track but it is definitely not wanted in a gun acoustics sound effects library, so I had to be very careful to set the release times so that the closing effect would not be perceived. Then I could use Izotope RX to gently erase the remaining noise. For this I most often used the Gain function, set to really small values, never more than -0,5dB, and then step by step lowering the volume of the affected areas until only the blast and the echoes were left, with the upper frequencies blending smoothly with the tail as if the wind noise had never been there.
To make sure that no noise got left unnoticed we put a Waves L1 limiter on each track while working, so that the noise got pushed up and was really evident. The goal was to be able to listen to all channels at once, with the limiters on, and there would be no disturbing noise audible. This was to ascertain that the final customer can use the sounds in their projects, be able to slam a heavily set limiter, and not have to experience noise pumping through the speakers.
The editing sounds like it was an incredible amount of work. How long did it take to edit, clean, and organize the material?
Cleaning the library took an enormous amount of work. Some microphones were for obvious reasons easier to deal with since they were closer to the sound source and thus less affected by the elements. But most of the others had to be treated quite (sometimes very) extensively to become acceptable for the library release.
The library is now available as The Urban Gun Acoustics Library. Can you tell us a bit about the final collection?
Yes, at last it is finished and ready for release! For the sound designer buying it we offer three different gun-types (SMG, AK, LMG), shooting both single shots and bursts, recorded at 6 different locations in an urban factory setting. The guns are recorded with high quality microphones (Sennheisers, Neumann, Sanken, etc.) and recorders at perspectives ranging from being taped onto the gun, up to standing 120 meters away from the shooter. Echoes and slapbacks ringing between the buildings are carefully maintained and the files are meticulously cleaned and curated, with extensive metadata embedded in the audio-files. All sessions are lined up in tandem and for ease of use there is for each location a Pro Tools and Reaper session included, so that the takes and performances are easily accessed and viewed.
We believe that this library will be a great help for anyone sound designing urban battles and more.
