Foley artists normally produce sound effects by mimicking the action of characters on a screen, but for Universal Pictures’ new horror-thriller, The Invisible Man, the Foley team from New York’s Alchemy Post Sound faced the novel assignment of creating the patter of footsteps and swish of clothing for a character who cannot be seen.

Directed by Leigh Whannell, The Invisible Man centers on Cecilia Kass (Elisabeth Moss), a Bay Area architect who is terrorized by her former boyfriend, Adrian Griffin (Oliver Jackson-Cohen), a wealthy entrepreneur who develops a digital technology that makes him invisible. Adrian causes Cecelia to appear to be going insane by drugging her, tampering with her work and committing similarly fiendish acts while remaining hidden from sight.

The film’s sound team was led by the LA-based duo of sound designer/supervising sound editor P.K. Hooker and re-recording mixer Will Files. Files recalls that he and Hooker had extensive conversations with Whannell during pre-production about the unique role sound would play in telling the film’s story. “Leigh encouraged us to think at right angles to the way we normally think,” he recalls. “He told us to use all the tools at our disposal to keep the audience on the edge of their seats. He wanted us to be bold and create something very special.”

Hooker and Files asked Alchemy Post Sound to create a huge assortment of sound effects for the film. The Foley team produced footsteps, floor creaks and fist fights, but its most innovative work involved sounds that convey Adrian’s onscreen presence when he is wearing his high-tech invisibility suit. “Sound effects let the audience know Adrian is around when they can’t see him,” explains lead Foley artist Leslie Bloome. “The Invisible Man is a very quiet film and so the sounds we added for Adrian needed to be very precise and real. The details and textures had to be spot on.”

Alchemy’s Andrea Bloome, Ryan Collison and Leslie Bloome

Foley mixer Ryan Collison adds that getting the Foley sound just right was exceedingly tough because it needed to communicate Adrian’s presence, but in a hesitant, ephemeral manner. “He’s trying to be as quiet as possible because he doesn’t want to be heard,” Collison explains. “You want the audience to hear him, but they should strain just a bit to do so.”

Many of Adrian’s invisible scenes were shot with a stand-in wearing a green suit who interacted with other actors and was later digitally removed. Alchemy’s Foley team had access to the original footage and used it in recording matching footsteps and body motions. “We were lucky to be able to perform Foley to what was originally shot on the set, but unlike normal Foley work, we were given artistic license to enhance the performance,” notes Foley artist Joanna Fang. “We could make him walk faster or slower, seem creepier or step with more creakiness than what was originally there.”

Foley sound was also used to suggest the presence of Adrian’s suit, which is made from neoprene and covered in tiny optical devices. “Every time Adrian moves his hand or throws a punch, we created the sound of his suit rustling,” Fang explains. “We used glass beads from an old chandelier and light bulb filaments for the tinkle of the optics and a yoga mat for the material of the suit itself. The result sounds super high-tech and has a menacing quality.”

Special attention was applied to Adrian’s footsteps. “The Invisible Man’s feet needed a very signature sound so that when you hear it, you know it’s him,” says Files. “We asked the Foley team for different options.”

Ultimately, Alchemy’s solution involved something other than shoes. “Like his suit, Adrian’s shoes are made of neoprene,” explains Bloome, whose team used Neumann KMR 81 mics, an Avid C24 Pro Tools mixing console, a Millennia HV-3D eight-channel preamp, an Apogee Maestro control interface and Adam A77X speakers. “So they make a soft sound, but we didn’t want it to sound like he’s wearing sneakers, so I pulled large rubber gloves over my feet and did the footsteps that way.”

Invisible Adrian makes his first appearance in the film’s opening scene when he invades Cecilia’s home while she is asleep in bed. For that scene, the Foley team created sounds for both the unseen Adrian and for Cecilia as she moves about her house looking for the intruder. “P.K. Hooker told us to imagine that we were a kid who’s come home late and is trying to sneak about the house without waking his parents,” recalls Foley editor Nick Seaman. “When Cecilia is tiptoeing through the kitchen, she stumbles into a dog food can. We made that sound larger than life, so that it resonates through the whole place. It’s designed to make the audience jump.”

Will Files

“P.K. wanted the scene to have more detail than usual to create a feeling of heightened reality,” adds Foley editor Laura Heinzinger. “As Cecelia moves through her house, sound reverberates all around her, as if she were in a museum.”

The creepiness was enhanced by the way the effects were mixed. “We trick the audience into feeling safe by turning down the sound,” explains Files. “We dial it down in pieces. First, we removed the music, and then the waves, so you just hear her bare feet and breath. Then, out of nowhere, comes this really loud sound, the bowl banging and dog food scattering across the floor. The Foley team provided multiple layers that we panned throughout the theater. It feels like this huge disaster because of how shocking it is.”

At another point in the film, Cecilia meets Adrian as she is about to get into her car. It’s raining and the droplets of water reveal the contours of his otherwise invisible frame. To add to the eeriness of the moment, Alchemy’s Foley team recorded the patter of raindrops. “We recorded drops differently depending on whether they were landing on the hood of the car or its trunk,” says Fang. “The drops that land on Adrian make a tinkling sound. We created that by letting water roll off my finger. I also stood on a ladder and dropped water onto a chamois for the sound of droplets striking Adrian’s suit.”

The film climaxes with a scene in a psychiatric hospital where Cecilia and several guards engage in a desperate struggle with the invisible Adrian. “It’s a chaotic moment but the footsteps help the audience track Adrian as the fight unfolds,” says Foley mixer Connor Nagy. “The audience knows where Adrian is, but the guards don’t. They hear him as he comes around corners and moves in and out of the room. The guards, meanwhile, are shaking in disbelief.”

“The Foley had a lot of detail and texture,” adds Files. “It was also done with finesse. And we needed that, because Foley was featured in a way it normally isn’t in the mix.”

Alchemy often uses Foley sound to suggest the presence of characters who are off screen, but this was the first instance when they were asked to create sound for a character whose presence onscreen derives from sound alone. “It was a total group effort,” says Bloome. “It took a combination of Foley performance, editing and mixing to convince the audience that there is someone on the screen in front of them who they can’t see. It’s freaky.”