For those of you who like your music loud, here’s a fun fact: sound can kill! Only if it’s greater than 135 decibels, that is. You’re not likely to get such high-power sound waves on your iPod, but there does exist a sound system that could kill you – the European Space Agency’s monster sound horn.
The horn is the most powerful of its kind in Europe. When turned to maximum volume, there’s absolutely no chance of survival. It is a part of ESA’s Large European Acoustic Facility (LEAF), a test chamber used to perform acoustic noise tests on spacecrafts to make sure no damage occurs during rocket launches.
The sound test chamber is 16.4 m tall, 11 m wide and 9 m deep; one of its walls houses the massive horn. When nitrogen is shot through the horn, it can produce incredibly powerful sound – over 154 decibels. The effect is something like standing close to multiple jets taking off at once – enough to permanently deafen a human.
Such sounds can cause so much damage that they are actually used as weapons. Less powerful sound waves are released to control crowds, as a burglar deterrent and in counter-terrorist settings. These waves cause humans to experience nausea or discomfort. Acoustic grenades can cause more damage – they generate between 120 and 190 decibels of sound. According to a German research, a blast of over 210 decibels can damage internal organs, resulting in injuries and death.
Fortunately, the ESA’s horn wasn’t designed to be a weapon. It is isolated behind reinforced walls and only operated when all the safety doors are closed. Steel reinforced concrete walls with epoxy resin coating are used to contain the noise and produce a uniform sound field inside the chamber. So no human will ever be able to hear the horn’s true power (even if they did, they probably wouldn’t live to tell the tale).