These Canadian College Students Are Working on Downing Drones With Sound

Courtesy WSJ - Prandtl Dynamics. I had an amplifier just like this in my 1981 Chevy El Camino.

The Ukraine War has introduced the world to an ongoing arms race between drones, electronic warfare jammers, and fiber-guided and autonomous drones to counteract the jammers.

One could be forgiven for thinking that AI-powered, autonomous drones like the Texas-made V-Bat are the final iteration in this game of cat and mouse.

But now, several Canadian students have figured out a way to down those autonomous drones as well. They even invested $17,000 of their own money to make it a reality.

Turns out, blowing drones out of the sky doesn’t require missiles, lasers, or even sophisticated hacking. Nope. Just good old-fashioned sound waves.

Yes, the same force responsible for shattering wine glasses and making subwoofers rattle car windows can now take down drones with an acoustic death ray.

Enter Prandtl Dynamics, a scrappy Canadian startup that has figured out how to weaponize sound against enemy drones—because, let’s face it, in a world where Russia is throwing everything but the kitchen sink (and maybe even that) at Ukraine, any tool to stop their flying death robots is welcome.

To be clear, using sound waves to down drones is not a new idea – researchers in South Korea in 2015 performed the foundational groundwork of disrupting a drone’s electronic gyroscope with sound waves.

And while the researchers from the Korea Advanced Institute of Science and Technology (KAIST) dialed in the science, the issue was how to scale it up for use on the battlefield.

Ten years later, this anti-drone marvel started as a dorm room experiment by four engineering students from the University of Toronto. Using repurposed car speakers—because nothing screams “military-grade tech” like scavenging from a Honda Civic—these students built a device capable of making drones wobble like a drunk uncle at a wedding. At close range, the thing outright crashes them.

And the Canadian government loved it.

The team entered their contraption in a 2024 counter-drone competition held by Canada’s defense department, where it won second place and a tidy C$375,000 ($262,000) in prize money.

Not bad for a bunch of college kids competing against corporate behemoths. Their company, Prandtl Dynamics, is now developing a battlefield-ready prototype expected to hit the 100-meter attack range mark. That’s right—an oversized Bluetooth speaker may soon be bringing down enemy drones from a football field away.

How Does It Work?

Members of the team working on the antidrone system include Parth Mahendru, Anna Poletaeva and Michael Acquaviva, checking a frequency. WSJ

The science behind Prandtl’s weapon is surprisingly simple: drones rely on delicate gyroscopes to stay upright. Blast those gyroscopes with the right frequency, and they freak out—overcorrecting until the drone nosedives into the ground like a failed Russian invasion plan.

Now, you might be thinking: “Wouldn’t it be easier to just blast these things out of the sky with a good old-fashioned shotgun?”

At super close range, sure… and it would be a lot more satisfying.

But the researchers at KAIST and our Canadian startup heroes at Prandtl Dynamics have figured out a far nerdier (and arguably more effective) way: hitting drones with targeted sound waves to scramble their electronic brains.

At the heart of every drone is an electronic gyroscope—a tiny, delicate sensor responsible for tracking the craft’s orientation, tilt, and movement. This little device is what keeps a drone stable, making constant micro-adjustments to ensure it doesn’t just flip over and eat dirt.

Without it, even the best drone pilot in the world might as well be trying to fly a brick with propellers.

So, how do you mess with a gyroscope?

With resonance.

You’ve probably seen that neat party trick where someone runs a finger around the rim of a wine glass until it starts to hum.

That’s resonance—when sound waves hit an object at just the right frequency, making it vibrate. Well, it turns out drones also have a breaking point when exposed to the right kind of noise.

While most high-end electronics are built to withstand everyday sounds (so your microwave beep doesn’t accidentally down a $1,000 DJI drone), the researchers at KAIST found that many commercial drones—especially the cheaper models—use bargain-bin gyroscopes that do resonate under the right conditions.

When that happens, the gyroscope starts vibrating uncontrollably, misinterprets the drone’s position, and overcompensates with erratic rotor adjustments—essentially throwing a mid-air temper tantrum until the drone crashes.

Of course, before you go cranking your home stereo and trying to take down the next drone you see, there’s a catch: you need powerful sound waves.

In lab tests, researchers successfully crashed a drone by attaching a speaker directly to its frame—which is great if your counter-drone strategy involves physically strapping an air horn to enemy UAVs (spoiler: it does not).

But what about real-world applications? Prandtl Dynamics and other researchers speculate that with the right frequency and enough power—say, 140 decibels (about as loud as a jet engine at takeoff)—drones could be disabled from up to 130 feet away.

That might sound impractical, but the military already has sound-based weapons like the LRAD sound cannon, which can accurately target people five miles away.

US military acoustic hailing devices are acoustic devices capable of outputting intelligible sound at very high volumes. The distance at which acoustic hailing can be effective varies based on several factors including the sound level, directionality, and frequency of the acoustic source, the sensitivity and directionality of the receiver, and the transmission channel environment.

US Navy acoustic weapon. Public domain

The sound level diminishes or attenuates with distance. Consequently, as a general rule, higher source levels have a greater range.

The term “acoustic hailing device” came into common use following the suicide attack on the USS Cole while it was at a port in Yemen in 2000. Following this attack, the United States Navy established a requirement for a sound weapon.

In theory, then, a focused acoustic weapon could jam a drone’s gyroscope mid-flight, sending it tumbling without permanently frying its circuits.

And that’s the beauty of this method—it doesn’t destroy the drone outright, it just makes it uncontrollable. Which means that if, say, Russia’s ever-evolving fleet of kamikaze drones starts falling out of the sky like confused pigeons, you can bet Prandtl’s Sound Matrix had something to do with it.

Prandtl’s system, which they call the Sound Matrix, uses an acoustic “laser” to focus sound waves on a drone’s key sensors, rendering them useless.

And in case you’re wondering if this is just a fluke, the team has already developed 35 different acoustic waveforms to target various drone models. Basically, if it flies, they’re figuring out how to make it fall.

And here’s the real kicker: unlike traditional jamming methods—which Russia and Ukraine have been playing a never-ending game of cat-and-mouse with—this works against drones that don’t rely on radio signals.

No GPS? No problem.

Whether it’s AI-powered drones using visual navigation or command-line-controlled kamikaze units, they can still be sonically swatted out of the sky.

The Future of Sound-Based Warfare

Prandtl isn’t stopping at battlefield applications. They’re working on a 4kg “backpack” version to protect soldiers in the field—an invisible boombox that kills drones. And let’s be real: in an age where drones are buzzing over everything from battlefields to backyard barbecues, civilian applications aren’t far behind. Annoyed by a neighbor’s drone spying over your fence? Future Prandtl customers might just be able to aim a speaker at it and—poof—it’s gone.

Meanwhile, military buyers are already lining up. The US Army, Ukrainian defense contractors, and others have all come knocking.

And given how effective it could be against the swarms of cheap suicide drones Russia has been using, don’t be surprised if Ukraine starts deploying these against the Kremlin’s flying scrap heaps sooner rather than later.

The vast majority of Russia’s drones use cheap Chinese gyroscopes simply because sanctions have largely been able to prohibit this type of high technology from reaching the country – (at scale).

This means that most, if not all, of Russia’s drones would be susceptible to sound disruption.

Russia, of course, will likely try to counter this with their usual methods—like throwing more drones at the problem or claiming their drones are immune because the ghost of Lenin wills it so.

But considering their track record, it’s only a matter of time before some unlucky Russian soldier watches his expensive drone spiral into the dirt because a Canadian college kid figured out how to weaponize Taylor Swift.

Welcome to the future of drone warfare. It’s loud, it’s cheap, and for Russia—it’s about to be a very annoying problem.

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