Nubert Lautsprecher, HiFi- und Surround-Elektronik

This is the most powerful sound system in Europe – but no human being could survive hearing it at maximum output.

Engineer Kees van Zijtveldt is standing beside the largest sound horn of ESA’s Large European Acoustic Facility (LEAF), capable of subjecting satellites to the same noise a launcher produces as it takes off and flies through the atmosphere.

LEAF is an integral part of ESA’s ESTEC Test Centre in Noordwijk, the Netherlands, a collection of spaceflight simulation facilities under a single roof. One wall of the chamber – which stands 11 m wide by 9 m deep and 16.4 m high – is embedded with a set of enormous sound horns. Nitrogen shot through the horns can produce a range of noise up to more than 154 decibels, like standing close to multiple jets taking off.

As a safety feature, LEAF can operate only once all the doors are closed. Steel-reinforced concrete walls safely contain its noise, coated with epoxy resin to reflect noise to produce a uniform sound field within the chamber. The chamber itself is supported on rubber bearing pads to isolate it from its surroundings.

This looks a bit like a giant ear canal, but in a way, it's the opposite. It's the largest horn in the most powerful sound system in Europe. The system's maximum output, according to the European Space Agency, would kill any human exposed to it.

The horn is part of the European Space Agency's Large European Acoustic Facility in Noordwijk, the Netherlands. The facility blasts sound at spacecraft components to test whether they're able to withstand the intense noise of launch. There are four horns, to create sounds in a range of frequencies. ESA engineers send nitrogen gas through the horns to create noise of more than 154 decibels.

Whether that's enough to literally kill is unclear. (There are so many variables. Did the agency mean "kill you on contact" or "kill you if you're sealed inside the facility for a while"?) At the very least, it would cause some serious damage. The eardrums rupture at around 150 decibels. The lungs rupture at around 200 decibels.

For safety, the facility has half-meter-thick walls made of steel-reinforced concrete coated inside with epoxy resin, which reflects noise into the chamber. It also won't operate unless all of its doors are closed.