On Saturday, hundreds of thousands of Serbs took to the streets of Belgrade for a mass protest. They say the police used a sonic weapon against them. Videos on social media showed protesters suddenly scattering in panic during a moment of silence in memory of the victims of the Novi Sad train station incident. Serbia's Interior Ministry denies the use of a sonic weapon, but has not given a specific explanation for what may have triggered the protesters' reaction.
What is this acoustic means of attack and what consequences can it have on those affected?
What are sonic weapons?
Acoustic weapons are not lethal. They fire sound waves that produce an extremely loud noise. Unlike normal sound waves, which weaken as they move away from the point of emission, acoustic signals from sonic weapons can be heard at full strength at a distance of one kilometer. This is due to the fact that these waves are fired with high pressure.
The closer you are to this weapon, the more severe the pain it causes. This type of weapon can reach a maximum sound level of 150-160 decibels. For comparison: The noise from a jet engine reaches 130 decibels, the sound level during a normal conversation is about 60 decibels, and the roar of babies ranges between 80 and 100 decibels.
Different people have different sensations of excessive sound volume, it also depends on the frequency of the tone. Generally, for those with normal hearing, noise becomes unpleasant when it is louder than 90 or 100 decibels. The painful threshold is reached at around 120 decibels.
Tinnitus, hearing loss, mental problems
With very loud noises such as those from acoustic weapons, the sound waves attack the eardrum with great pressure and can cause damage. The usual instinctive reaction is to pinch the ears, which is why acoustic weapons are also called "acoustic handcuffs" - at a certain point the hands cannot be used for anything else.
In addition to the earaches that begin to be felt immediately after reaching a strength of 120 decibels, permanent hearing damage can also be caused. However, it is not only the ears that are affected - psychological damage can also be caused, as surprised people become victims of an "unexpected" attack against which they cannot defend themselves.
If the sound wave hits people with great pressure, this can even have deadly consequences: with extremely loud noises, such as from an explosion, the sound waves can rupture the lungs of people in the immediate vicinity.
Noise as a means of waging war
Loud noises have been used in warfare for centuries. For example, the indigenous people of what is now the United States used war drums to communicate with each other over long distances and to intimidate and confuse the enemy. During World War II, noises were also used as a psychological weapon: the Nazi air force equipped its bombers with sirens that made a loud sound when diving. Then it caused even greater panic among those attacked.
Nowadays, sound weapons have been used on cargo ships off the coast of Somalia to drive away pirates. Police in Greece used such weapons in the summer of 2021 against migrants arriving illegally from Turkey. Actions by producing loud noise were also carried out by American police during protests on the occasion of the G-20 summit in Pittsburgh in 2009.
There are also suspicious cases related to the use of sound weapons without tangible or very quiet noises with a high frequency. In 2016 and 2017, American diplomats in Havana complained of health problems such as hearing damage, dizziness and insomnia. According to American data, some embassy employees even had concussions and lost their hearing. One possible explanation is an attack with a new type of sonic weapon.
Later, similar symptoms were also observed among American diplomats in other cities such as Vienna and Berlin. Investigations into the so-called Havana syndrome did not reach a clear conclusion. It is believed that sonic weapons were not used.
Author: Carla Bleiker