Peter Albrechtsen is an award winning sound designer/editor whose past work includes films such as "The Girl With The Dragon Tattoo”, “Dunkirk”, and “Thelma”, among many others. When you look at the amount of work his career spans and the amount of detail that he has put into his work, it becomes obvious why he was chosen to be the sound supervisor for National Geographic’s The Cave.

The Cave is a stirring portrait of courage, resilience and female solidarity. For besieged civilians in war-torn Syria, hope and safety lie underground inside the subterranean hospital known as the Cave, where pediatrician and managing physician Dr. Amani Ballour and her colleagues Samaher and Dr. Alaa have claimed their right to work as equals alongside their male counterparts, doing their jobs in a way that would be unthinkable in the oppressively patriarchal culture that exists above. Following the women as they contend with daily bombardments, chronic supply shortages and the ever-present threat of chemical attacks, The Cave delivers an unflinching look at the Syrian war and some of its most unlikely heroes. I had the chance to talk with Peter about how he crafted the soundscape for The Cave, check it out below.

“Instead of making us feel like we were at a distance, the sound should be subjective and tell us how they experience their world.”

V - How much of the audio in the film came from production sound, conversely how much is recorded foley and edited sound effects? How did you balance them all together?

PA - It was a super complicated film shoot because these cinematographers were in a zone where no one else could get in, it was really hard to bring in equipment. The production sound was very rough, a lot of it was from camera mics which didn’t sound great. Lars Ginzel, the re-recording mixer/dialogue supervisor who worked with me on the whole film spent a lot of time cleaning up the dialogue to make it audible.

We added a lot of Foley to help create the feeling of natural sound. Heikki Kossi, a Finnish Foley artist that I work with on all my projects, did an amazing job. He has these tricks of recording with the microphone a bit off axis so that everything sounds much more natural. There's a lot of Foley going on to create all the steps and movement that give off the feeling of the characters being there in the room.

We also spent a lot of time building the ambiences and backgrounds to make them sound as realistic as possible. All of the hospital sounds were in this isolated place, they couldn’t be coming from modern equipment. A lot of the equipment consisted of old hospital machinery so I got hold of different recordings of old machinery to really make it seem real.

Building a natural feeling for the scenes took a lot of work, and on top of that, there were all of the effect-heavy components, like bombs, guns, planes, and jets, all of which are a big part of the sound of the film. Feras Fayyad, the director, is really into sound and we had talked for about a year and a half before we got to the mix. Since he is Syrian and had lived in Syria, he really knows how the sound influences your experience of being in a place where there's war going on constantly. He was very keen on using sound for creating the environment of war. I had time to gather all these different sounds and get the right Russian jet sounds, recordings from Syria, guns going off in the street and all of these various elements that created the environment because we started talking so early.

Feras had the idea from the very beginning that we should do it in Dolby Atmos, because he wanted the sound to envelop you. He wanted you to have this feeling of the war going on above you, like it feels in the cave. The vision for the sound design of the film came from that first meeting.

V - What was the process like for cutting sound effects and ambiances?

PA - I was the supervising sound designer/editor and we had a couple of sound effects editors. One from Beirut, Rana Eid, knew about living in the Middle East in a war zone. There's an element about the film where it's so much about these women, this underground hospital is led by women so I thought it was really important to have a female voice in the sound.

We started developing sounds quite early on because they couldn't finish the edit before they had these sounds. Many of the scenes are about the characters listening, so you couldn't really finish the cut before you actually felt like they were reacting to sounds.

In terms of timeline, Rana was the first to do some sound effects editing, next Foley artist, Heikki, who was in Finland, worked on the foley. Lars Ginzel, who was in Germany, then worked on mixing those together. We had a dialogue editor in Sweden, and we had another sound effects editor who helped out, who’s from Norway. We did some voice recording with Amani, the main character, in Turkey, and we finished the mix at Skywalker Ranch in the U.S. The composer and music mixer were both English. With all of the different people helping out during the process, the sound has been through 12 different nationalities.

It's the kind of job you can only do with modern technology where you can send files back and forth on through secure FTPs. It was a big job and a lot of work, but it was a blessing because there was enough time to develop a clear kind of vision for the sound. Since Feras had so many ideas for the sound, we actually had the time to experiment and play around with things. It was a long process, but a good one.

V - Was it emotionally difficult to constantly be watching this very powerful story over a long period of time?

PA - I have two kids and watching all of these kids being in a war zone… it’s hard and it's really, really demanding. It's a difficult film to watch, but I also feel when you're sitting there digging into the details, you are so focused on making everything work well that when you've seen the film a couple of times your focus on the work starts to take you away from what’s happening on screen. The first time I watched the film I couldn't do anything for the rest of the day, it was tough. Once you start diving into all of the details though you begin to concentrate on making everything feel right and making everything touching or powerful or dynamic to get all of these textures right for the film.

Before we did any sound design the movie felt more like a reportage. Feras was really insistant on being subjective, cinematic, and having the sound make you feel like how it felt in the cave. Instead of making us feel like we were at a distance, the sound should be subjective and tell us how they experience their world.

There's a scene where they talk about being hypersensitive to the surroundings and there's many scenes where they're really listening to what's going on and listening for the planes and explosions above. All of this means that we're really listening together with them. The nurse who's also cooking, Samaher, watched the film just recently and she said that for her, this was exactly what it felt like and how it sounds like to be in the cave. For me, hearing that was like… wow. There was this feeling we'd been working so much on getting emotionally right and to hear her say, "Perfect, this was how it feels to be there," that was amazing.

V - Is it challenging to mix a film in a different language?

PA - Language is a inspiring thing and not something that's an hindrance in any way. It's very interesting to mix a movie which is in a language that you don't understand because suddenly you start listening to the language in a different way. You start listening to the words like they're a piece of music. Listening for the musicality of the dialogue and how the rhythm flows is important. Fortunately a lot of the basic dialogue editing was done during the picture editing, then when we did a pass on the dialogue I went through it together with Feras, who speaks the language. He was able to hear if there were any minor mistakes.

When working in a language that you don't understand, the dialogue can feel more like an instrument playing among other instruments. It can also be interesting to approach sound design like a piece of music. I usually say that the composer has a guitar and a piano, and that I have birds or cars passing by, or in this film, explosions or beeps from hospital machines. You can tell a lot about what kind of emotions the characters have based on their speech.

“I usually say that the composer has a guitar and a piano, and that I have birds or cars passing by, or in this film, explosions or beeps from hospital machines.”

V - Most people have never been in a war zone. How did you and the director approach creating this sonic environment where there's an explosion at any time and war is constantly going on in the background?

PA - It was a great help that Feras Fayyad had lived there and knew what it was like living in a war zone like that. One of the things he talked about was traumatizing sounds and for him, for example, the sounds of the jets were very traumatizing. It's a sound that when you hear it, it cuts through your bones and brings up all of these traumas. Emotionally, it’s tough to deal with. It goes beyond a normal sound and travels through your body. It’s physical and psychological at the same time.

Hearing Feras talk about how the different sounds of these experiences felt and how they should feel was important. When he talked about sounds, it was very rare that he said, "Okay, I need a door that's closing there, or I need a beep there." He really talked about the emotions and how the emotions of the sounds should be. Even down to these stretchers with their wheels on, when they bring in people who are wounded from the war, the sounds of the wheels of the stretchers were so emotionally heavy. The meaning of these sounds is something that he had experienced and talked about with the nurses and doctors at the hospital.

It’s a war film, and in a war movie sound has an enormous role. At points, I was thinking about Das Boot, a German war movie which takes place in a submarine. You're in the submarine with these soldiers and they just hear things going on outside of the submarine, but you don't see anything. You just hear sonars or explosions going off. In a way, it's a very similar philosophy with The Cave, there's so much of the film that's about hearing things that are not seen.

V - When it comes to heavier moments with explosions and jet planes flying overhead, are there any sound design/mixing tricks you used to create more of a feeling or to make those elements appear hyper realistic?

PA - One of the things I really love about working in Dolby Atmos is the amount of layers you can have spread out around you while still holding clarity. The explosions, for example, had a lot of layering. There’s the idea of an explosion where one element is the explosion itself, then the explosion makes a rattle or an earth shaking sound, and then it hits something else, a window breaks, and then a building shakes and more metal rattles. There's a lot of layers in the explosions in this film that make the explosions more real.

Sometimes explosions in big Hollywood movies are so clean (and that can be amazing in an action movie), but in a film like The Cave, you want it to feel gritty and you want it to feel real. I layered lots of elements for these different explosions because it felt much more real and it got gritty, but still had this powerful impact. Sometimes I do that by distorting sounds, but a lot of it comes from recording different elements and mixing them together.

PA (cont.) - I got a hold of these recordings of Russian jets that were so powerful. Feras really wanted them to sound evil so we played around with different special sounds that could give them an edge. On top of the jet sounds we tried out different animal sounds. Tim Nielsen at Skywalker had recorded some very roaring, powerful sounds a few years back that worked perfect together with the jets. He couldn't even remember what they were anymore, but creative textures like that were layered with the jets and made them more evil.

There's a scene in the beginning of the film where it's the first time that our main character is going through the city and you hear this jet flying above her. For that, I took all kinds of sounds that could create this feeling of rattling. The physicality of sound often comes from a feeling where it's not just that one sound you hear, it's also impacting everything else. We had Nathan Moody, a Californian sound designer and musician, create these amazing sounds where he got metal to rattle with all kinds of synth textures and low sub-woofer sounds.

A lot of those rattles, I played around with in places to make it feel like everything was moving and vibrating because these sounds were so loud. There were a lot of tricks being played around within the mix. Another interesting thing was that some of these sounds I actually sent off to the composer, Matthew Herbert. He used some of those rattles in the music as well so there's elements from the sound design that was also turned into elements in the music, which makes for a really nice interplay.

V - Looking back, what are your final thoughts on the experience of working on The Cave?

PA - We were very fortunate to be able to have a long process where we could play around with sound. We had a long mix, which started here in Denmark where I'm based, and then moved to Skywalker to do the final mix. I think we ended up mixing for four weeks, which is quite unheard of for a documentary, but for this it was really great because it meant that we had time to develop the sound and really dig into all of these details. At the same time, since the film is such a tough one, it also meant that we could have time to reflect a bit, to lean back and not be totally emotionally wasted while actually having the time to get an overview. I'm very proud of how the whole thing came out.

Check out “The Cave” at https://www.nationalgeographic.com/films/the-cave/#/

Follow Peter Albrechtsen on Twitter @lydrummet