NAIROBI, Kenya- A powerful high-pitched sound pierced through streets along the University Way in Nairobi on Thursday as police sought to disperse protesters marking the second anniversary of Kenya’s Gen Z protests.
The unfamiliar device mounted on a police vehicle quickly drew attention, with many Kenyans asking what it was and whether it had been used before.
Known officially as a Long Range Acoustic Device (LRAD), the technology is designed to broadcast voice commands over long distances or emit an intense warning tone capable of reaching hundreds of metres away.
It has been used by security agencies around the world for crowd management, maritime security and emergency response, but remains controversial because of concerns about its potential health effects.
What is a Sound Blaster?
A sound blaster, commonly referred to as an LRAD, is a highly directional acoustic system that projects concentrated sound toward a specific area instead of broadcasting in every direction like a conventional loudspeaker.
Developed in the United States in the early 2000s, the technology was initially designed to help naval vessels communicate with approaching boats over long distances and deter piracy without using lethal force.
Since then, police, military and emergency services in several countries have adopted the devices for public announcements and crowd management.
How does it work?
The device contains dozens of small speakers arranged in an array that work together to produce a focused beam of sound.
Operators can switch between two main functions:
- Voice mode – broadcasts instructions, evacuation notices or public safety announcements clearly over long distances.
- Alert mode – emits an extremely loud warning tone intended to attract attention or encourage people to move away from a restricted area.
Unlike ordinary public address systems, an LRAD concentrates sound in one direction, meaning those directly in front of it hear a much louder signal than people standing to the side.
Why do police use it?
Police agencies say the technology allows officers to communicate with large crowds before resorting to physical force.
Authorities typically cite several advantages:
- Delivering clear instructions over noisy environments.
- Warning crowds before further crowd-control measures are introduced.
- Managing large public gatherings.
- Securing sensitive facilities or restricted zones.
- Assisting during disaster evacuations and emergency operations.
During Thursday’s anniversary demonstrations, Kenyan police used the device as they dispersed protesters and opposition leaders heading toward Parliament, where security had been significantly reinforced with razor wire, water cannon trucks and roadblocks.
Where else has LRAD been used?
The technology has appeared in several high-profile security operations worldwide.
Police departments in the United States have deployed LRADs during protests and major public events. They have also been used in Australia, Japan, South Korea and India for crowd management and emergency communication.
Naval forces from several countries also use LRAD systems to warn unidentified vessels approaching military ships or commercial vessels in piracy-prone waters.
Is it safe?
Manufacturers describe LRADs primarily as communication devices rather than weapons.
However, when operated at very high volume, the warning tone has generated concern among medical experts and human rights organisations.
Possible short-term effects reported in medical literature include:
- Temporary hearing loss.
- Ringing in the ears (tinnitus).
- Ear pain.
- Headaches.
- Dizziness.
- Disorientation.
The risk depends on factors such as the sound level, duration of exposure and distance from the device. Experts say prolonged exposure at close range to extremely loud sound may increase the risk of more serious hearing injury.
Because of these concerns, civil liberties groups have questioned the use of LRADs during demonstrations, arguing that they should be deployed only when necessary and proportionate.
Why is its use in Kenya significant?
The appearance of the sound blaster during the June 25 commemorations marked one of the first widely documented uses of the technology during public demonstrations in Kenya.
The anniversary marches commemorated the Gen Z-led anti-government protests of June 2024, when demonstrators stormed Parliament during opposition to the Finance Bill before a security crackdown left at least 60 people dead, according to rights groups.
Protest organisers this year described the gatherings as peaceful memorial processions seeking justice and accountability for those killed.
As security agencies continue to adopt new crowd-control technologies, the deployment of LRADs is likely to intensify debate over how police balance public order with the constitutional right to peaceful assembly.