Serbia’s President Aleksandar Vucic has denied that his police forces used a banned ‘sonic weapon’ to disperse protesters in Belgrade. In a statement, he said, “I have had the opportunity to see this weapon abroad, and it emits a strong, piercing sound. That sound was not heard on the streets of Belgrade on Saturday (March 15) night.” Serbia is currently witnessing mass protests against Vucic and his government over several issues, including allegations of widespread corruption and nepotism. According to some military experts, the authorities used a sonic weapon to produce a piercing noise to curb the protests. Under the country’s police law, the use of such a weapon is illegal. Here is a look at sonic weapons, how they work, their type, and health effects. What is a sonic weapon? Acoustic or sonic weapons are devices that deliver very loud sounds over long distances. They can be designed to emit painful audible or inaudible sound waves. These devices can also be used to act like voice amplifiers to deliver voice messages or other sounds. Although sound amplifiers have been around for centuries, the use of this technology for crowd-control purposes goes back to the early 1990s. In 2004, the United States military for the first time used specialty devices that were able to project loud sounds over very long ranges in Iraq. How do sonic weapons work? Such weapons usually comprise hundreds of modern transducers — an electronic device that converts energy from one form to another — to create highly concentrated and amplified sound. “This fairly narrow beam can focus on specific targeted areas. The sound is designed to be controlled by police officers who can alter the frequency, level, quality, and duration of the alarm,” according to a report by Physicians for Human Rights (PHR), a US-based non-profit organisation. What are the different types of sonic weapons? There are three main types of sonic weapons: 1. Long-range acoustic device (LRAD): The device is manufactured by US-based Genasys Inc, which was earlier known as the LRAD Corporation. It has a range of 8,900 metres for intelligible speech, and produces a highly directional “beam” of extremely loud sound which can go to up to 160 decibels (dB). For comparison, standing directly behind a jet engine as it takes off is between 130-140 dB, and a nearby gunshot produces around 150 dB. “Anything over 140 dB will cause pain for most people, but even sounds over 120 dB can cause permanent hearing damage from even short periods of exposure,” according to a report by The Conversation. 2. Mosquito: This device produces very high-pitched sounds that are audible and painful to only younger people — usually teenagers and those in their twenties. It does not affect older people (30 and above). James Parker, an expert in sound and law at the University of Melbourne in Australia, told CNN, “It’s not audible to adults because your hearing fades as you get older.” 3. Infrasonic weapon: This is a newer technology and could deliver very low-frequency sounds that would be inaudible but could cause pain and disorientation. Experts are still investigating its capabilities. Parker told CNN that infrasonic devices are likely to be the hardest to weaponise. “There are (sonic) devices that are used as weapons, but none that I know of use infrasound,” he said. What are the health effects of sonic weapons? These weapons can cause significant harm to the eardrums and delicate organs of the ears and/or hearing loss. Although using earplugs can reduce the sound by 20–30 dB, this may not be enough to avoid significant injury. The impact depends on a person’s distance from the sound, duration of exposure, and preexisting bodily conditions. Loud noises, for example, emitted by LRAD can cause a sensation of ringing ears, also called tinnitus, which can last for minutes after the exposure or for days. “Other sound injury symptoms include headaches, nausea, sweating, vertigo, and loss of balance. Signs of more serious injury include vomiting and mucus or blood from the ears,” according to a report in Pitchfork. Human rights organisations such as PHR note that there is not enough literature on the effects of sonic weapons. PHR also highlights that these weapons are “indiscriminate, causing harm or pain to protesters, bystanders and law enforcement, despite the narrow beam in which sound is concentrated.”
