The Apprehension Engine: history’s most terrifying musical instrument

This hybrid musical agitator is part guitar, part percussion instrument, all discomfiting aural adventure. We learn more about the most unsettling instrument ever made, and speak to its creator Mark Korven.

Apprehension Engine

Image: Mark Korven

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There are many avenues by which musicians might make a living other than starting a band, getting signed, and releasing records. One such career pathway is the world of scoring for television, film, and video games.

These scores are often emotive, as their purpose is to aid in setting the mood of a certain scene. Horror media, in particular, often calls for unsettling sounds that, outside of Nine Inch Nails records, are not commonplace in the music consumed by the mass public. The pursuit of eerie sounds has led to the invention and adaptation of several unique instruments.

In 2016, Canadian composer Mark Korven combined a number of existing instruments with sound-effects generators to create an all-in-one device dubbed the Apprehension Engine. The tool, which boasts a host of distinctly creepy sounds, has been used in his work on such films as 2019’s The Lighthouse and 2015’s The Witch and, prior to the pandemic, he toured with it too.

The original Apprehension Engine made its debut at the Toronto International Film Festival.

Since the instrument’s creation, a further 25 or so have been built and sold – many of them to notable composers. One of the first went to Trent Reznor.
“You can bow these things,” said the NIN frontman of his new toy. “There’s no right or wrong way to use it. And they tell you when you get it, it really requires you learning how to play it and figure it out. It pissed us off, ’cause when we got it, it sounds shitty. I’m not instantly good at it.”

Apprehension Engine
Image: Mark Korven

Korven’s original Apprehension Engine is decorated with some of his favourite comments from his YouTube channel: “This guy has a jar full of hands, I’m sure of it”; “It’s 3:00 AM…why am I doing this to myself?”; “This sounds like me on any instrument”; “Disturbing. Will it not make any happy sounds at all?”; “My wife make scarier sounds in her sleep”; plus a comically simplified version of Reznor’s, which reads, “Sounds like shit”.

The instrument is challenging to play, requiring much experimentation and practise until it can be mastered. There are many ways to draw sound from the Apprehension Engine. It features a single guitar string and pickup, to be used with an E-bow and heavy distortion, as well as an Eventide Harmonizer, and a reverb tank from a Fender amp (which can also be played itself). There’s also a primitive hurdy gurdy, plus four steel rulers and rods that can be bowed, hit and plucked. A tray of nuts and bolts can be manipulated with a magnet, and the friction mallets can be used by dragging them across the instrument’s body. There are three piezo pickups hidden inside, along with a single magnetic humbucking pickup. Confused? The video below should help place those elements in context.

As Korven explains, the difficulty that comes with learning to play the Apprehension Engine is to be expected. “All of it is difficult to learn,” he says. “Trying to repeat one of the weird, invented sounds takes a lot of work and attention to subtlety. Exploring E-bow harmonics, man, that was hard. Every little 16th of an inch changes the sound totally when you have a slack string and a ton of distortion.”

The original instrument was built in a short span of time, as Korven was keen to unveil it at the Toronto International Film Festival in 2016. This condensed design period led to the original instrument bearing a few quirks.

“Since my AE [Apprehension Engine] is one of the slapped-together ones, it’s filled with quirks and problems,” says Korven. “It took me a while to figure out that I just had to use the problems as advantages in order to find new sounds. It’s not a very reliable instrument. It’s about the constant exploration of its quirks.”

As if the sonic range of the instrument wasn’t vast enough, when Korven plays the instrument, it is usually accompanied by an Eventide Harmonizer, three Boss loop pedals, and a custom-built distortion pedal.

Apprehension Engine
Image: Mark Korven

With so many unique attributes rolled into this single instrument, it stands to reason that its name should be unique as well. ‘The Apprehension Engine’ captures the essence of the hybrid tool’s disconcerting sonic palette. But where does it come from?

“We were building the thing and I described it to my friend, Zeb,” Korven tells us. “He thought for a second then said, ‘The Apprehension Engine’, and I knew right away that that was it.”

The Apprehension Engine is only about six years old but it’s already begun evolving. The instrument has also inspired DIY builders to knock up their own versions hybrid tools of scary sonic potential. There’s even a Facebook group dedicated to them. In their own efforts, most builders typically try to copy the original design but some add their own twist. Others have used effects pedals to broaden the range of sounds even further.

Making musical instruments is an art form that dates back thousands of years. This madcap invention proves that there is still ground to be broken. The Apprehension Engine is an exciting creation carving out sonic spaces that other instruments struggle to reach.

For more information on The Apprehension Engine, check out apprehensionengine.com

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