From loudspeakers to precision acoustic tools: The engineering behind modern directed sound systems
Directed acoustic energy systems have evolved significantly from their origins in public address and crowd communication. Today’s precision sound platforms are designed not just to project speech but to deliver force. Using calibrated sound pressure and directional sound projection technologies, these systems are reportedly capable of producing non-lethal deterrent effects at a distance with minimal mechanical footprint. The result is a class of devices often referred to as sonic weapons, though in most cases they are classified as non-lethal acoustic deterrents.
Commercially available systems such as the LRAD series, developed by Genasys Inc., are among the most widely documented examples of directed acoustic energy platforms in active use. The company’s product guide states that the LRAD 100X emits up to 137 decibels at one metre, while the LRAD 450XL can reach up to 145 decibels under peak conditions. These levels place the devices well above the commonly accepted pain threshold and into the range where sustained exposure may cause permanent hearing damage. Despite frequent references in media to “sonic weapons,” Genasys and other manufacturers typically classify these systems as non-lethal acoustic deterrents intended for law enforcement, military and maritime use.
The transition from basic loudspeakers to directed acoustic energy systems reflects a broader trend toward precision sound engineering. Initially used for broadcasting in large venues or events, loudspeakers were built to maximise reach without necessarily controlling direction. However, modern designs allow engineers to focus audio output in tight beams and enable both intelligible communication and area denial functions. This principle, once limited to public spaces, has since been adapted for use in security and defence scenarios.
Central to these systems is their ability to generate and manipulate sound pressure using refined signal processing techniques. Devices like the LRAD 450XL use high-powered transducers to emit tightly controlled sound waves. The design projects audio over long distances with minimal loss and the signal remains clear even in acoustically difficult environments.
While the original concept of beamforming involved multiple sound sources working in concert to direct energy, modern deterrent systems use a single transducer array to achieve similar directionality. Though these designs differ technically from true beamforming arrays, they are functionally aligned in their use of focused acoustic energy for control and clarity.
Such systems also incorporate digital signal modulation, allowing for on-the-fly adjustments based on environment, distance and use case. Variables such as wind, humidity and background noise are accounted for through adaptive engineering, ensuring that tone, frequency and volume remain consistent and effective.
As outlined in the LRAD Safety Statement by Genasys, these systems are designed to establish safe standoff zones, inform and direct, and prevent misunderstandings, thereby resolving situations without the use of kinetic force. However, the high output of directed acoustic systems could potentially carry significant health risks. Sound levels exceeding 140 decibels — frequently found in systems like the LRAD 450XL — could rupture eardrums or cause permanent hearing loss. The National Institute for Occupational Safety and Health (NIOSH) recommends dosimeter settings for noise exposure in the range of 80–140 dBA. Similarly, the Occupational Safety and Health Administration (OSHA) advises that impact noise should not exceed a 140 decibels peak sound pressure level. As such, these systems must be operated within strict safety protocols, particularly in close-range scenarios or during extended deployment.
The market for non-lethal weapons, including acoustic deterrents, is reportedly poised for continued growth. Analysts from The Business Research Company valued the global non-lethal weapons market at approximately $8.22 billion USD in 2024, with projections estimating an increase to $8.93 billion USD by the end of 2025. This expansion is reportedly driven by rising demand from law enforcement, private security and maritime sectors seeking alternatives to kinetic force.
The development of directed acoustic energy systems represents a significant shift in how sound is engineered and applied in security contexts. From their roots in public address to their current role in deterrence, these technologies reflect a broader trend toward precision, portability and non-lethality. While often labelled as sonic weapons in media and public commentary, their operational use typically falls under the banner of acoustic deterrence — applied to manage threats or communicate warnings without inflicting permanent harm.
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