Recording Explosion Sound Effects with Barney Oram

Hi Barney, thanks for taking the time to chat with us today. What have you been working on recently?

Hello! I have been lucky to be quite busy recently, working with my amazing colleagues over at Sweet Justice Sound Ltd. We’ve had the opportunity to work on a number of exciting titles that have been released recently, including Demon’s Souls, Returnal, The Ascent, and many more. Every project is a huge learning curve for me and it’s a privilege to work alongside a talented team of creative people. 

Tell us a bit about your background: How did you get into sound design? 

I began fiddling with sounds and music when I was very young, and it quickly became an obsession that continued through my education and became a career. I made electronic music for many years as a teenager, and was introduced to sound design while I was at university. I decided to pursue sound design within the context of video games, and after a lot of trying and failing, I made my way into the industry!

Let’s talk about the Krotos Explosions Library! Making a library of explosives sounds is quite a challenge. How did the idea for the library come about?

In the last few years I set myself the personal challenge of recording as many explosive sounds as I could, both to learn more about the process of recording very loud sounds, and also to improve my skills on the design side. I began small; recording fireworks and small firecrackers, then explored recording cannons and larger film-industry standard pyrotechnic explosives, and eventually found my way into recording some much larger explosive charges. 

I managed to connect with a few experts that handle high explosive substances, only a small handful of whom operate in the UK, and was able to record C4, TNT, Semtex and a variety of other explosive types.

I thought these would be a perfect subject for use within Weaponiser, and approached Krotos with the idea for putting together a custom explosives recording session and a resulting collection of bespoke explosive recordings.

What were the first steps toward organising an explosives recording session?

One of the most important considerations when planning an explosives session is finding the right environment to do the recordings in. Successful recordings depend upon a suitable location, with a variety of factors determining usability; Firstly, explosives are loud. REALLY loud. The ideal location is as far from residential areas as possible. As well as humans, considering impact on potential nearby livestock is imperative also.

Secondly, thinking about the acoustic nature of the space is vital, on account of the characteristics it will impart to the final sound. An explosion is effectively just a very loud burst of noise, and the unique character comes from the reaction of the physical space it is recorded in. 

The combination of these aspects makes finding a perfect venue very tricky, and I spent quite a considerable amount of time trying to locate somewhere suitable. Eventually I managed to find an industrial quarry that was amenable to my specific requirements. It was an ideal distance from civilization, physically it was very large with a lot of interesting terrain, and they’d blasted rock in the quarry previously so weren’t alien to the concept of explosives.

Once I’d secured the location, it was a question of narrowing down specifically what substances we wanted to record, and figuring out my microphone and recorder choices for the session.

What considerations do you make when preparing your microphones for recording explosives?

Given the extremely loud nature of the source in this case, thinking about the characteristics of a microphone and how to use them effectively is critical. For this specific subject, I tend to group my microphones into three categories: close, medium, and far. This defines the distances I place them from the firing point, and also helps to inform the specifications of the microphone selection that is used.

In this case of this library, I mostly focused on dynamic microphones for the close perspective. This makes sense because dynamic mics cope well with very high SPL sounds, and they generally don’t distort particularly easily. The frequency response is usually a little more limited than a condenser mic, but the results are very useful sounds. I also used a couple of handheld recorders on some of the closer perspectives, as they can sometimes produce interesting results.

For my medium distance, I used a selection of cardioid, omni and shotgun condenser microphones. At the 40-60m range (depending on size of explosive) you tend to get a nice response on the transient still, without overloading the capsule. In this session I used two of the Crown SASS microphones, and you can hear they’re slightly too close on a few takes, and the result is some clipping at source. In the new world of 32-bit recording clipping is less of a problem than it used to be, but when the physical shockwave of an explosion hits a microphone too violently, it produces a distortion that cannot be saved by 32-bit. 

The far perspectives tend to have a nice rounded transient, with a bit less high frequency energy and much more low end presence. I used a mixture of condenser microphones at this distance, and some handheld recorders. One of the real standout distant perspectives in this library comes from the very unassuming Tascam DR05 handheld recorder, placed at 300m for a few takes. Despite having tiny capsules, the Tascam captures low frequencies with a fantastic depth and tightness, resulting in a really interesting bass-heavy distant sound.

What are the differences between the explosive charges included in the library?

I cannot go into too much detail about the specifics of the explosives, but for those with limited knowledge about explosive materials, I will explain what the different names mean.

For starters, the main explosive charges we recorded for this library all belong to the ‘plastic explosives’ family; TNT, C4 and Semtex. Plastic explosives are typically low reactive and very stable, meaning they can be manipulated physically without any risk of reaction. They require detonators to be initiated, as well as a supportive explosive substance called ‘detonating cord’, or detcord. We recorded some lengths of detcord on its own, as the reaction is quite considerable. We also recorded a quantity of black powder, which has a slightly deeper, less percussive sound.

Generally speaking most of the explosive materials sounded reasonably similar, as the largest contributor to the sound of the explosive is the environment it is fired in, so we varied the source point within the quarry so as to introduce subtle changes in the acoustic response. 

How is the Explosions library laid out?

I have tried to set the library out in a way that makes the most sense for the end user. Each explosive charge exists in its own audio file, with the weight specified, the variation number specified, and the microphone distance and microphone type all detailed in the file name. If we take for example ‘EXPLReal_Detcord 12g 04 25m DPA 4007 AB’, we can see the UCS naming convention at the start (EXPLReal), the specific explosive charge with weight detailed (Detcord 12g), the variation number (04), the distance of the microphone from the source (25m) and the specific type of microphones used plus some information about the configuration type (DPA 4007 AB). I used a few of the same types of microphones in two different places during this session, such as two of the Crown SASS mics and two pairs of Sennheiser MKH 8040s. I have indicated these doubles with a simple ‘01’ or ‘02’ at the end of the filename.

I have cleaned up and added fades to all files, so no additional preparation work has to be done by the sound designer prior to use. 

The library comes with complete UCS compliant SoundMiner metadata, to ensure these sounds will easily integrate into your existing library and be readily searchable. There’s also some additional information included in the metadata, such as the type of recorder used for each take.

What are some of the challenges you faced recording this library?

The quarry was mostly made up of chalk, and this presented some interesting challenges whilst recording the explosives. Firstly, chalk is quite easily loosened and some of the larger explosive charges brought down some crumbling chalk debris on the quarry wall face. We were a little concerned that larger chunks might be brought down, but thankfully this didn’t occur. Our explosives technicians were also concerned about the possibility of shards of slate or other harder rock fragments present among the chalk, so we elevated the larger explosive charges from the ground (with a small wooden stick) so as to avoid lifting much debris. We also took the precaution of actively looking out for any large pieces of debris flying through the air after an explosive had gone off, in case anything was picked up.

Recording powerful explosives is always a considerable challenge and I worked extra hard to make sure this session ran smoothly and was a fruitful success. I often find that extensive preparatory communication and thorough planning is critical to ensure a complex recording session is successful. 

What makes the Explosions library unique?

The quarry space we settled upon has a very interesting acoustic response, and I think it has given the library a very specific style of sound. The explosives are tight, quite punchy and have a lot of natural low end resonance to them. We fired the charges from a number of different locations within the quarry, some with more of a natural resonance contributing to enhancement of the low end, and some producing interesting changes to the sound of the environmental decay after the transient blast. On some of the larger explosives, you can hear quite an unusual natural phasing of the environmental reflections. The quarry was essentially divided into two by a large mound of chalk debris running through the centre, and I believe this natural phasing was due to the interplay of reflections running concurrently down through these two sections. On a few takes you may also hear a low metallic rumble; this is due to a large oil container that was nearby to some of the larger explosives. There’s also a few takes that feature a sprinkling of light debris after the explosive blast; as I mentioned earlier, this is some of the loosened chalk falling around the microphones.

I decided to leave these small idiosyncrasies in the recordings, as I felt they bring a certain life and uniqueness to the sounds that I consider desirable.

Can you tell us a bit about the Weaponiser presets you put together to accompany this library?

Weaponiser is a really excellent tool because it is quick and easy, and very flexible for making changes to suit your design requirements. I spent some time putting together a set of designed presets, which are suitable to be dragged and dropped into any project. I made full use of Weaponiser’s functionality, giving the user lots of options to customise the presets and tweak as they need. They are also easily built upon, with the option for custom user recordings and assets to be added to the base preset for further personalization of the sound.

In addition to the base explosive recordings, I also supplied a selection of ‘toolkit’ assets to be used in Weaponiser. They’re broken into modular parts, such as debris, sweeteners, and enhanced transients, so as to be immediately useful when creating custom presets. They’re semi-designed and quite aggressive, providing the user with a selection of instantly usable source material.

Thank-you for your answers to these questions; finally, what advice would you offer to designers using these recordings to craft their own explosion sounds?

I’ll happily offer some thoughts based on what I’ve learned designing explosions. Keep your design simple! You do not need to stack endless layers in pursuit of a big sound. Try to stick to a minimal selection of elements, each doing a very specific job without overpowering its neighbors. Avoid sounds that add noise and mud, and focus on finding the right sound for the job. 

Often a lot of the detail and sonic interest of an explosion sound exists in the tail, so experiment with using debris and other sweeteners to bring extra character to your design. 

Have fun with it! Try putting a very unusual sound at the core of your design and see how you can build a compelling explosion around it. Sometimes you’ll find the movement and energy required to bring a sound to life in the most unexpected sources.

It has been a pleasure chatting about this library and I’m extremely excited to hear how it’ll be put to use!

Explosion Sound Effects Library is a powerful library created by Barney Oram. It comes packed with 3.8 GB of explosive goodies including black powder, C4, Detcord, Semtex, and TNT. The Explosions Sound Effects Library includes thousands of pre-designed variations available straight out of the box and a huge range of multi-mic’d recordings plus designed sweeteners.

Buy Explosions Sound Effects Library