Crafting the Captivating Sound of ‘Knock at the Cabin’ — with Sound Supervisor David Forshee

Director M. Night Shyamalan's latest theatrical release Knock at the Cabin tells the unsettling story of a family who encounters of group of strangers in a remote cabin, forcing them to make an unthinkable choice to avert the ultimate disaster. Since the story mainly unfolds in one location, sound played a crucial role in defining the character of the space and helping the audience to clue into what's happening off-screen.

Here, supervising sound editor David Forshee talks about building up the insect sounds in the woods using custom recordings from recordist Colin Hart as the base, working with the Alchemy Post foley team to help emphasize each character's personal traits and helping to add weight and texture to the handcrafted weapons, designing apocalyptic events (like a tsunami) yet making it feel like it was captured using a smartphone camera, working sounds against the score, and more! Please note: Contains some spoilers

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Interview by Jennifer Walden, photos courtesy of Universal Pictures; Colin Hart; David Forshee

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That remote Vrbo cabin in the woods may have looked like the ideal retreat from the din of civilization in Director M. Night Shyamalan’s new film Knock at the Cabin, but young Wen and her parents Eric and Andrew who were vacationing there found their peace disturbed by four strangers wielding handcrafted weapons and raving about the end of the times. To stop the apocalypse, they said, Eric or Andrew must choose which of the two should die.

Since the main story unfolds in just one location – the cabin – the sound needed to engross the audience, to make them feel present in the situation with the young family and their captors. The exterior scenes in the woods are awash in insect sounds as young Wen captures grasshoppers with Leonard. The cabin interior sounds exactly as you’d expect a cabin in the woods to sound, wonderfully creaky and reverberant with sounds bouncing off the wooden walls and floors.

New York-based supervising sound editor David Forshee worked with the foley team at Alchemy Post Sound, who went beyond the requisite footsteps and cloth rustles for the film by recording a library of custom creaks for Foshee to layer in as needed, and they helped create the sound of the characters’ handcrafted weapons by capturing sounds that added a feeling of texture and weight.

Forshee also worked with recordist Colin Hart, who ventured out to the film shoot location in Tabernacle, New Jersey, and recorded ambience that served as a base layer for the exteriors. Hart also recorded grasshoppers (that he captured and released) to accurately represent the sound of the grasshoppers that Wen and Leonard capture in the film.

Forshee’s co-supervising sound editor, Jill Purdy handled the dialogue and ADR at Sound Dogs Toronoto. She also created a breath track that adds a feeling of panic and anxiety to the scenes.

Here, Forshee talks about building the sound of the world inside and outside the cabin, designing impactful sound for apocalyptic events – like airplanes falling from the sky and a tsunami that overwhelmed beachgoers – yet making them sound as though they were captured on a smartphone camera, using the Dolby Atmos surround field to put the audience in the scene with the characters, and so much more!

Knock at the Cabin – Official Trailer

I love how overwhelming the bugs sound in the beginning; they’re very full in the surrounds. I grew up in Pennsylvania, and it felt like I was back there in the woods…

David Forshee (DF): That was definitely the idea. Night had a lot of thoughts about the opening specifically, like the foley. It’s all so exposed and so sound-focused. The way he described it to us was that we should feel the waves of the wind and insects.

As I was playing with the sound there, it became almost like a meditation.

As I was playing with the sound there, it became almost like a meditation. It creates that meditative, fairy-tale type of vibe. We do our spotting session and I get his ideas, and I approach things in an intuitive way. I’ll try ideas and see what feels right. We played with a lot of elements in the mix making full use of the Dolby Atmos surrounds by having insects flying all around. The idea was to create this very immersive experience because these were Wen’s last “normal” moments on earth.
 

Although I heard the mix in 5.1, I could certainly hear all the details you put into the backgrounds. They never felt flat or felt like just a few ambient layers of bugs. You could hear the bespoke insects as they moved from one side of the room to the other. The right-side ambience sounded different from the left, which sounded different from the front. It was so well-crafted….

DF: That was so important for this single-location film. The opening is what gets you. Night comes out of the gates with this. There isn’t much exposition. We just get right into it.

This scene between Wen and Leonard plays out for nearly 10 minutes, so having it evolve with, as Night described, waves of wind and hearing every detail was critical to telling that part of the story.

Yes! This takes place in mostly one location, and mainly inside the house. I appreciated the use of abstract sounds and off-screen sounds to intensify the tension in these situations. If you took all those sounds away, it’s just eight people in a house…

DF: Especially in the way it was shot, it feels very claustrophobic. And much does happen off-screen, like the break-in sequence. There were a lot of conversations with Night and Noemi Katharina Preiswerk (picture editor) about exactly where the characters are in the cabin.

…Ja-Ann Wang printed out a blueprint of the cabin, so we all had that layout in mind as we were working…

In the pre-mix, our assistant sound editor Ja-Ann Wang printed out a blueprint of the cabin, so we all had that layout in mind as we were working and could talk about where a character is in relation to everything else. This allowed us to get very precise with the panning, to tell the story that was playing off-screen. That was a big part of it.

…and could talk about where a character is in relation to everything else. This allowed us to get very precise with the panning…

In terms of the tension, there were so many sounds that we used. One of the big contributors was the foley and the footsteps, and the creaks on every footstep. We spent a lot of time on finding the right creaks and making sure every footstep felt just right. Leonard, for example, had to feel like the 300-lb. man that he is.

So I said that eight people were in the cabin, but I know technically only seven people were physically there. Because of how the sound team handled the panning – pin-pointing sounds to specific spots in the cabin off-screen – and having those sounds move in relation to the camera, it felt like the camera was the viewer, and that you’re essentially the eighth person in the space. It’s not a feeling you often get in cinema, that you’re an unseen character actually there as a witness to what’s happening…

DF: This is the perspective of the audience, the eye of the filmmaker. This is Night’s telling of the story. He has such a singular vision; he’s a legend in his own right. And that comes across in every one of his films. They’re distinctly his, and I think that’s part of it, being able to create that perspective.

The slow pans gave us the freedom to pan dialogue and pan the sounds of the insects outside coming through the door.

The way it was shot, too, has a lot to do with that. So, huge credit to the DPs Jarin Blaschke and Lowell A. Meyer. The way the camera moves and how the shots were composed, it gives you that sense that you’re the eighth person in the room. The slow pans gave us the freedom to pan dialogue and pan the sounds of the insects outside coming through the door. All that helped to establish that feeling that you’re there, witnessing this crazy story.

I love little details in sound, like how the sound of the insects played so prominently outside, and so when the door opens inside the cabin, you hear the insects’ sounds flood into the space. And then when the door closes, their sound is occluded by the door…

DF: That’s one of my favorite moments – the way that it’s shot and the story at that point. Andrew is tied up to the chair and he’s looking outside, and the sound of those insects represented freedom. I loved how the sounds work with the score and the way the camera is panning. That’s pure cinema to me.

Photos Courtesy of Colin Hart

Did you get to go out to PA and capture any recordings?

DF: I really wanted to go out myself but we were on a very compressed timeline so I worked with a recordist named Colin Hart, who doesn’t live too far from Night in Pennsylvania. And he lives very close to where the film was shot, which was in Tabernacle, New Jersey.

He recorded in ambisonic and stereo all around the cabin, in the tree house, and near the lake.

Colin came on very early, even before I started work on the film, and we had him do a day of recording out where they shot the exteriors of the cabin. He captured a bunch of ambisonic ambiences. He recorded in ambisonic and stereo all around the cabin, in the tree house, and near the lake. All of that was the inspiration and basis for the backgrounds that we built. We definitely went a lot further with the insect sounds, but these recordings were a good base.

He also recorded a bunch of grasshoppers and built a very cool setup to get clean recordings of the grasshoppers with the Sanken CO-100k ultrasonic microphone, which allowed us to do some really fun pitched-down grasshopper designs.

Then, the foley team recorded a library of wild creaks that weren’t to picture but that we could place in the edit.

As you mentioned earlier, the foley sounds played so prominently and played a huge role in this film – like the sound of Leonard’s boots making him feel like a 300-lb guy. Who did the foley on the film?

DF: We worked with Alchemy Post. Leslie Bloome is the primary foley artist. I worked very closely with Nick Seaman, the foley supervisor/editor. They went above and beyond. Very early on in the process, they were sending me different samples of possible footsteps, and surfaces they could use.

The surface they chose…had a bit of creak to it, and then we were adding and embellishing that with creaks all over the place

We played with recording the footsteps separate from the creaks and then combining them, and with choosing a surface that has nice creaks so they’re baked into the sound. We ended up doing a hybrid. The surface they chose, and that felt right, had a bit of creak to it, and then we were adding and embellishing that with creaks all over the place. It was a fun collaboration and there was a lot of back and forth between myself and the foley team.

Night had a very keen ear for foley, and would pick up on every nuance of the foley performances. Not all directors are so tuned into foley or understand the power of sound. For instance, in the opening shot of the film with Wen in the forest, the first note we got was that the footsteps needed to feel like a little girl. There was something about the first iteration that was a little too careful and measured. So, we went back and did another pass where it felt more careless and a little lighter, not so measured and heel-toe. Night was totally right. It’s one of those little things that he caught and that made me realize what a consummate filmmaker he is. He picks up on every little detail.

What about the homemade weapons that the ‘Four Horsemen’ carry? These are weapons they crafted themselves, and they’re very important to the story. Was that foley, or hard effects?

DF: It was a combination. I love the flail that Sabrina uses because of the chain sounds that we could play with. That was a really nice texture because for the other weapons we really only hear when they’re being handled specifically, or if they’re being put down. But as Sabrina walks through the cabin, the chain sounds follow her. And, of course, every time a character puts their weapon on the wood floor, we hear the resonance and feel the weight of that. It was meant to be very threatening, especially Redmond’s weapon. When he was frustrated, he would bang it on the wood floor, and it was very important to Night that it had the proper weight and felt menacing.

Another very effective way you added a feeling of stress and panic was through your use of a breath track. (I’m sure this was the wonderful work of co-sound supervisor Jill Purdy!) When you feel anxious, your heart races and your breathing gets faster and more pronounced. I appreciated how present the breath track felt in the mix because it added some much stress to the scenes…

DF: Yes! Jill is a wizard. She did the dialogue editing and she was amazing at getting these performances and cutting them in a way that felt so natural. It was important to Night that we felt with the characters in these tense moments. Jill did that with the breaths, and with the alt takes she cut in. Lines that I thought for sure we’d need to get in ADR, Jill made them work by cutting in alt takes. She worked her magic, and her work is incredible.

I noticed in the end credits that there were a lot of ADR credits. Was there a lot of ADR used in the film?

DF: Those were mostly ADR recordists and mixers. We were on an email thread with the producers and it was very important to Jill that all the ADR recordists and mixers got credit because sometimes they don’t end up in the film credits. Maybe they’ll be listed on IMDb or something, but they aren’t listed in the film’s end credits. And so Jill went out of her way to make sure that they got the credit they deserved.

Right on! When you work on a film, it’s very rewarding to see your name in the credits and disappointing when you don’t!

DF: Right! Relatively speaking, there wasn’t that much ADR in the film. There were a few lines here and there, but we needed lines from every actor and they were all over the world so we had different ADR teams handling those recordings. That’s why there were so many credits.

I loved the sound of the airplanes falling out of the sky. It was so believable. Of course, that’s not something you can record, so how did you create that sound?

DF: I really had to think about the perspective: how big do we go with it, where are we in relation to the airplane, and so on. We tried a few variations for this, some were more over the top. But the whole idea with the disaster scenes is that they’re found footage or a Facbook Live kind of footage that’s being aired on the news. So, we could only take it so far with sound.

I really had to think about the perspective: how big do we go with it, where are we in relation to the airplane, and so on.

There are moments when it’s filling the screen so you want to feel like you’re there. So, I did some research on actual plane crashes (there’s not a lot out there, but there is some) and I tried to be inspired by these real-life explosions and tried to imagine what it would sound like if it were recorded well, and then design that. So, it’s a very distant explosion. Having that distance in the one shot where you see all the planes falling actually made it creepier – hearing how it echoes across the space makes you feel the distance. That was very creepy to me, and made it feel ‘right.’

I thought you did an amazing job of making it feel credible, and making the audience believe what they were seeing. Like the tsunami wave, this was captured by someone on the beach with their smartphone. They’re eventually overtaken by the wave and their phone is still capturing what’s happening underwater for a little while. The sound there was so perfect…

DF: We had a lot of fun with that scene. For the most part, this is a very quiet film, so when there was an opportunity to go big – we really went for it.

You have to put yourself in that position mentally, and imagine what that would be like – imagine how much air that wave is pushing toward you. I built in a lot of wind and tonal elements that express this idea of a huge rush of wind as this wall of water is heading your direction. And the impact we tried to make as big as possible – to imagine what it would sound like as that water is hitting this phone and how it would interact with this tiny microphone. I wanted it to be as jarring as possible.

You have to put yourself in that position mentally, and imagine what that would be like – imagine how much air that wave is pushing toward you.

This was a big moment for the Atmos mix, where we were able to take advantage of the overheads. I want to credit re-recording Grant Elder, who mixed the foley, effects, and BGs. He was really using the Atmos surround field as much as possible and Night was 100% on board with exploring the space in Atmos whenever we could.

…Night is interested in having things sound good because they sound good.

Night pushed us. There are a lot of filmmakers that would have gone a more conservative route, sticking to the screen, but Night was more interested in exploring the space beyond just telling the story – to make it sound lush and magical. There’s something to that – to making something sound magical as opposed to just telling the story – and Night is interested in having things sound good because they sound good. That was refreshing. Obviously, there are limits and he had to reel us in occasionally, but he did really push us to experiment.
 

Did you know from the start that you were going to mix the film in Atmos, and if so, were you making Atmos object tracks for the mixers or pulling out specific elements meant for those tracks, like in the tsunami scene?

DF: We absolutely knew that this was going to be a theatrical Atmos mix, and so we were cutting elements that we know would be used as objects. Then there were times when it was dealer’s choice. Grant always had the option to ‘objectify’ certain elements. For instance, he could put the cicadas in the trees and that kind of thing.

…the most important thing is that, as you’re cutting, you have those elements there.

For me, the most important thing is that, as you’re cutting, you have those elements there. All these elements are orchestrated in a way that when you spread them around the room, they still work. They are still enough material to play with that you’re not leaving a big hole in the middle.

Grant and I had a cool workflow. The studio machine and my portable rig (where I was set up on the stage) had the exact same plugins. So our sessions were 100% compatible. That was amazing and made it a very collaborative process between us. I could make small adjustments on my rig and hear exactly what Grant would be hearing on the stage. And Grant had the freedom to nudge things around and make little edits on the fly because we were moving so quickly on this. That was very beneficial. There were no egos on the stage. We wanted whatever was best for the film. The best idea won and we were back and forth all the time.

The music in the film was super cool, and the sound design and music played together so nicely that it was hard to tell if something was score or design. Did you have the music to work against during editorial?

DF: Yes, in this case, we did. That isn’t always the case. From the very early cuts that I saw (from the first cut, actually), composer Herdís Stefánsdóttir‘s score (the demos) was already in there. That was pretty close to the final. There was a lot that changed when they recorded and mixed the score, like the dynamics, the 7.1 mixes, and how the designs translate with it, but it was so much better to work against a temp score that was close to the final than to have one that was completely different. There were no big surprises, which was amazing. When we got to the stage, it was all working together fairly well. And the few times when there was a conflict between score and sound effects, the dialogue and music re-recording mixer Christian T. Cooke was brilliant at finding the stem that was fighting and pulling it down a bit to let the sound effects do their thing. Everything had its moment, and it worked out so well.

L to R: David Forshee, Jill Purdy, Grant Elder, and Noemi Preiswerk (picture editor)

What have you learned while working on the sound of Knock at the Cabin that’s helped you to grow as a sound designer, or has changed the way you think about sound for film?

DF: This experience has reinforced the notion that sometimes the most difficult moments to pull off in a film are not the loud action set pieces, but the very quiet, exposed moments. There’s no hiding – every element of the soundtrack needs to be just right. Never underestimate the difficulty of finding just the right kind of creak or the perfect leaf rustle.

I’d like to acknowledge the hard work of the sound team on the film:

Sound Credits:

Supervising Sound Editors – Jill Purdy, David Forshee
Re-recording Mixers – Chris Cooke, Grant Elder
Assistant Sound Editor – Ja-Ann Wang
Sound Effects Editor – Natalia Saavedra Brychcy
Sound Effects Recordist – Colin Hart
Additional Sound Editor – Rachel Wardell
Mix Tech – Zack Booth
Foley Editor – Nick Seaman
Foley Artists – Leslie Bloome, Shaun Brennan, Curtis Henderson
Foley Mixers – Ryan Collison, Connor Nagy
Mix Facility – Soundtrack New York
ADR Mixers – Bill Higley (Soundtrack), Andrew Rice (Todd AO), Hunter Berk (Soundtrack), Simon Diggins (Goldcrest), Nick Roberts (De Lane Lea), Andre Kelman (Soundtrack), Michal Fojcik (Sound Mind)
 

A big thanks to David Forshee for giving us a behind-the-scenes look at the sound of Knock at the Cabin and to Jennifer Walden for the interview!

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