Sonic weapon Sonic and ultrasonic weapons ( USW ) are weapons of various types that use sound to injure , incapacitate , or kill an opponent . Some sonic weapons are currently in limited use or in research and development by military and police forces . Others exist only in the realm of science fiction . Some of these weapons have been described as sonic bullets , sonic grenade s , sonic mines , or sonic cannon s . Some make a focused beam of sound or ultrasound ; some make an area field of sound . Conventional sound . Sound recordings have been used as a weapon to confuse the enemy in battle , as part of psychological warfare , and as a means of torture . Culturally inappropriate music has also been used to discourage teenagers from loitering in civilian settings . For example , the metro trains in Melbourne used to broadcast classical music over the stations ' loudspeakers to discourage mischief . Usage and deployment . Extremely high - power sound waves can disrupt and / or destroy the eardrum s of a target and cause severe pain or disorientation . This is usually sufficient to incapacitate a person . Less powerful sound waves can cause humans to experience nausea or discomfort . The use of these frequencies to incapacitate persons has occurred both in counter - terrorist and crowd control settings . The possibility of a device that produces frequency that causes vibration of the eyeballs — and therefore distortion of vision — was apparently confirmed by the work of engineer Vic Tandy while attempting to demystify a “ haunting ” in his laboratory in Coventry . This “ spook ” was characterised by a feeling of unease and vague glimpses of a grey apparition . Some detective work implicated a newly installed extractor fan that , Tandy found , was generating infrasound of 18 . 9 Hz , 0 . 3 Hz , and 9 Hz . A long - range acoustic device has been used by the crew of the cruise ship " Seabourn Spirit " to deter pirates who chased and attacked the ship . More commonly this device and others of similar design have been used to disperse protesters and rioters in crowd control efforts . A similar system is called a " magnetic acoustic device " . ' mobile ' sonic device s have been used in Grimsby , Hull and Lancashire to deter teenagers from lingering around shops in target areas . The device works by emitting an ultra - high frequency blast ( around 19 – 20 kHz ) that teenagers or people under approximately 20 are susceptible to and find uncomfortable . Age - related hearing loss apparently prevents the ultra - high pitch sound from causing a nuisance to those in their late twenties and above , though this is wholly dependent on a young person ' s exposure to high sound pressure levels . High - amplitude sound of a specific pattern at a frequency close to the sensitivity peak of human hearing ( 2 – 3 kHz ) is used as a burglar deterrent . Some police forces have used sound cannons against protesters , for example during the G20 summit in Pittsburgh . Demonstrated infrasonic weapon . The U . S . Department of Defense ( DOD ) has demonstrated phased arrays of infrasonic emitters . The weapon usually consists of a device that generates sound at about 7 Hz . The output from the device is routed ( by pipes ) to an array of open emitters . At this frequency , armor and concrete walls and other common building materials allow sound waves to pass through , providing little defense . This presents logistic problems regarding operation of infrasonic weaponry without exposing operating personnel to the potentially damaging effects . Physicist and researcher Jürgen Altmann , however , has suggested that infrasound " does not have the alleged drastic effects on humans " in his paper " Acoustic Weapons . " While many sources make reference to military research into infrasonic weapons beginning with the work of Dr . Vladimir Gavreau , it is unclear as to whether or not these devices have potential use in conflict . Research . Some common bio - effects of electromagnetic or other non - lethal weapons include effects to the human central nervous system resulting in physical pain , breathing difficulty , vertigo , nausea , disorientation , or other systemic discomfort . Interference with breathing poses the most significant and potentially lethal results . Light and repetitive visual signals can induce epileptic seizures ( see Bucha effect ) . Vection and motion sickness can also occur . Cavitation , which affects gas nuclei in human tissue , and heating can result from exposure to ultrasound and can cause damage to tissue and organs . Studies have found that exposure to high intensity ultrasound at frequencies from 700 kHz to 3 . 6 MHz can cause lung and intestinal damage in mice . Heart rate patterns following vibroacoustic stimulation has resulted in serious negative consequences such as atrial flutter and bradycardia . The extra - aural ( unrelated to hearing ) bioeffects on various internal organs and the central nervous system included auditory shifts , vibrotactile sensitivity change , muscle contraction , cardiovascular function change , central nervous system effects , vestibular ( inner ear ) effects , and chest wall / lung tissue effects . Researchers found that low frequency sonar exposure could result in significant cavitations , hypothermia , and tissue shearing . No follow on experiments were recommended . Tests performed on mice show the threshold for both lung and liver damage occurs at about 184 dB . Damage increases rapidly as intensity is increased . The American Institute of Ultrasound in Medicine ( AIUM ) has stated that there have been no proven biological effects associated with an unfocused sound beam with intensities below 100 mW / cm² SPTA or focused sound beams below an intensity level of 1 mW / cm² SPTA . Noise - induced neurologic disturbances in humans exposed to continuous low frequency tones for durations longer than 15 minutes has involved in some cases the development of immediate and long - term problems affecting brain tissue . The symptoms resembled those of individuals who had suffered minor head injuries . One theory for a causal mechanism is that the prolonged sound exposure resulted in enough mechanical strain to brain tissue to induce an encephalopathy .