Ian Tuason and Nina Kiri behind the scenes of undertone. Photo by Dustin Rabin.

“I was never really into the occult before making this movie,” says Ian Tuason, writer-director of the new A24 horror film undertone. “After doing research, I started getting into it more. That manifested weird things into existence.”
A demonic “found audio” film, undertone came about, in part, due to Tuason’s background as a pioneer of immersive 360-degree VR horror shorts. Continuity Problems (2009) and Close Up (2011) found major success on YouTube before screening at the Marché du Film’s NEXT Pavillion in Cannes. His follow-up, the 360-degree live-action breakthrough 3:00am, racked up 9 million viewers on YouTube. Maybe he wasn’t “into” the occult, but he was certainly familiar with catering to its fanbase. 
Made for $500,000, undertone grossed double that just from Thursday box office previews. It has since grossed $9 million, a theatrical smash after premiering at Montreal’s Fantasia International Film Festival in July and amassing more buzz at Sundance earlier this year. 
“I always felt like surround sound in the theater would be a great opportunity to take what I learned and play around with it—to create a 3D soundscape and guide the viewer’s attention to different spaces around them,” Tuason says. “I just combined a bunch of things that I loved, like scripted podcasts and found footage.”
The film follows Evy (Nina Kiri), who co-hosts The Undertone podcast as the skeptical foil to her best friend Justin’s (Adam DiMarco) Agent Mulder–adjacent sensibility. They schedule episode recordings around a massive time difference between them, causing Evy—who recently moved back home to care for her comatose mother—to log on during the witching hour. The Undertone allows Evy to escape from the depressing day-to-day of administering palliative care—that is, until a fan-sent email containing an eerie audio recording lands in their inbox. The contents chronicle couple Jessa and Mike’s paranormal encounter with Abyzou, a female demon rumored to possess mothers and kill their children. Justin is characteristically wary of playing these files; Evy, meanwhile, insists on recording their reaction to its horrors, which are surely a hoax, in real-time. 
But Evy begins to encounter bizarre phenomena soon after. Her unconscious mother’s body inexplicably moves out of bed; lights flicker at random; a statue of the Virgin Mary returns to a bedside table despite multiple attempts to stow it in the back of a closet. “She’s slowly entering this audio nightmare until she’s entirely in it,” Tuason says of Evy’s arc. 
Unsurprisingly, the filmmaker’s experience as a sound-driven artist imbues undertone’s singular spookiness. This is particularly true of the film’s preoccupation with nursery rhymes revealing sinister messages when played backwards (“Baa Baa Black Sheep” apparently contains the lyric “lick the blood off). But only one fact explains the truly haunted feeling that the film gives off—Much like Evy, Tuason cared for both of his parents as they succumbed to cancer. 

“We filmed in the house my parents died in,” he says of the film’s single location. “You tell people that and they go, oh. Then there’s a moment of consoling, and then there’s a moment of, ‘Wait a minute, we’re filming in the same bedroom, right?’”
Production designer Mercedes Coyle refitted the house with overtly Catholic flourishes, a litany of crucifixes among them. As she was transforming the family home into a horror film set, Tauson moved back in to prep for production—the first time he’d lived in the house since his parents passed. 
“I could say that the set was haunted,” he laughs. He cites instances of lights flickering as they do in the film, but otherwise, he’s tight-lipped, claiming it’s “too long of a story.” Despite the supernatural activity that occurred on set, he seems generally unphased. 
“I kind of got desensitized after the whole caregiving experience—how dark it was,” he says. “I used to be really scared of ghosts. If I saw a ghost now, I would just go back to sleep.” As he’s since taken up residence in his parents’ house post-shoot—with all of Coyle’s touches still intact—he might actually be speaking from experience. 
There’s something to be said about the deliverance that comes from confronting one’s anguish through art. “When I was writing it, I didn’t really feel the catharsis of everything,” he says. “Not until I saw it on screen. Filmmaking is therapeutic.”
Toward the end of our interview, Tuason asks me if I can hear something. I lean in, the room tone in my own apartment suddenly resounding with a demonic tenor. 
“There’s a school next door and they’re having recess,” he clarifies. He was worried the children’s playful shrieks would diminish the audio quality of our interview. I, in fact, could not hear anything—and have never felt more relieved. 

 “I think audio is the most important element of a horror film—more important than picture,” he says. “Whatever you can imagine is always going to be scarier than what I can show you.” 
Judging by my previous reaction, this rings quite true. I ask him what film perfectly evinces this principle, and he replies, without the slightest hesitation, “Paranormal Activity.” 
His passion for the franchise is encouraging, considering that he was announced as the director of Paranormal Activity 8 back in December. But he doesn’t want to be confined to the horror realm for the rest of his career. 
“I’m gonna come out with a couple more horror films,” he teases. “After that, I’ll transition into sci-fi-horror. Then after that, sci-fi.” If Tuason is undeniably possessed by one thing, it’s creative ambition.