A24’s undertone breaks new ground in “aural horror,” a niche field that’s designed to challenge the audience’s imagination and could mark found-footage’s evolution.

Sound has a remarkable, underrated power that makes this aural sensation function like a kind of magic. A specific sound can operate as a formidable sensory trigger that brings you back to an exact moment in time or even resurrects the dead. There’s so much baked into a certain sound, both on an objective and subjective level, that makes it such a potent tool in horror.

Audio’s role as a time machine to the past is explored in “Erased,” Ian Tuason’s 2014 short film about a message that’s left on an ex-girlfriend’s answering machine that summons vivid memories of their relationship. Tuason unpacks the haunting, immortal aspect of sound in “Erased,” but it’s a concept that he fleshes out even further over a decade later in undertone, which digs deeper into the disturbing power of sound design to birth auditory nightmares.

It’s hardly the first horror film to tackle such territory. However, it feels like the culmination of decades of stylistic and genre reinventions that are finally ready to activate a raw, reactive side of horror.

Horror has a rich relationship with sound-based scares that speaks to the genre’s grander transformation. There are horror films that are obsessed with the art of sound design and audio artistry, such as Brian De Palma’s Blow Out or Berberian Sound Studio, the latter of which involves a sound engineer working on an Italian horror film who is forced to do foley work for disturbing visuals. There’s also Bruce McDonald’s Pontypool, which chronicles a zombie-like invasion that’s triggered through the sound of specific words. 

Berberian Sound Studio

Pontypool turns into a stunning deconstruction of the fragility of language as this vital tool deteriorates. It provides an audio-centric approach to the apocalypse that cultivates a comparable energy to A Quiet Place in terms of its unique relationship between sound and horror. Mike Flanagan’s Hush also gets tremendous mileage out of its lack of dialogue and heightened sound design, which is utilized to perfection through the film’s deaf and mute final girl protagonist.

To this point, auditory jump-scares manage to hit even harder than the traditional visual-based terrors. Everyone is familiar with the abrasive dissonance that’s experienced when headphones suddenly catch static or feedback crackles through a microphone. It’s a scare that lives in the audience’s mind and then slices right through it. There’s also a greater level of immersion that’s present because the audience is so thoroughly focused on the audio and, therefore, more vulnerable when something strikes.

In a modern context, aural horror is such fertile territory to explore due to the prevalence of podcasts, audio dramas, and other forms of experimental media that have returned to this stripped-down form of analogue horror. undertone succeeds as a film, but it’s also not hard to picture it being released as a series of audio tapes that were included in Fangoria magazine back in the ‘90s. Audiences have slowly been conditioned to accept aural horror projects so that a film like undertone doesn’t just connect, but even feels mainstream. It’s a film that still occupies horror’s fringe, yet it exists within a framework that’s been infinitely normalized through streamers and winds up feeling more accessible than The Blair Witch Project did in 1999.

Pontypool

This type of storytelling inherently pushes the audience to use their imagination to fill in the blanks because they can’t see what’s actually happening. In many ways, this is even more terrifying because it feeds into the audience’s fears and subconscious. undertone operates like an auditory found-footage experiment. It also carefully produces an intensified sound design that effectively amplifies tension and terror so that even mundane gestures put the audience on edge. There’s a creeping terror that’s heard and felt, but not seen, which can be even more frightening than a monster that emerges from the shadows or some lurking serial killer.

There are horror films that use sound design in creative ways and turn audio into a tangible plot point. However, there are also movies that present aural horror as the evolution of the found-footage genre, ironically enough, by scaling the medium back and stripping it down to its barest bones. Relying on audio-based horrors removes some of the standard tricks from the filmmaker’s toolbox, but it also has the potential to become the apex of where these types of stories have been headed. 

undertone follows this model and builds upon impressive, ambitious foundations that were previously explored in horror like Archive 81, Calls, and even certain elements of Skinamarink. Archive 81 is a horror podcast that ran for three seasons and a miniseries before getting adapted into a more conventional Netflix series. It involves an archivist who is hired to restore audio tapes from the ‘90s, which leads to the discovery of something demonic. Archive 81, much like undertone, features sequences where characters painstakingly loop audio until illogical noises begin to make sense. It’s an evocative experience that places the audience in the same place as the protagonists as they sift through sound for insight.

Archive 81. Mamoudou Athie as Dan Turner in episode 101 of Archive 81. Cr. Quantrell D. Colbert/Netflix © 2021

Alternatively, Apple TV+’s Calls depicts a collection of phone calls that are placed during an in-progress apocalypse as reality starts to melt. Troubling supernatural audio dramas are paired together with surreal synaesthetic waveforms. Undertone borrows from both of these aural horror stories and, in doing so, presents a new trajectory for the genre. It’d be a genuine shock if Tuason’s upcoming Paranormal Activity reboot doesn’t lean heavily into aural horror as it provokes through the use of tech-based terrors. It’s perhaps telling that Tuason cut his teeth in virtual reality storytelling, rather than podcasting. He’s used to creating dream-like scenarios in which the senses are infinitely skewed.

Undertone is a commendable stylistic tightrope walk that finds a way to have its cake and eat it too as it toes the line between found-footage and not, while embracing an aural horror ethos with every decision that it makes. There are constant auditory tricks on display that play with sound and distort perception so that the audience can’t trust what they see on the screen. Undertone creates a false sense of security that’s accomplished through the intimacy of noise-canceling headphones and auditory communications that feel like personal signals to the brain. It’s private, claustrophobic, and uncomfortable.

Undertone proves that a desire to push sound to unprecedented places is maybe the best way to disrupt a medium that’s so obsessed with pushing visuals to the extreme. 

undertone