High-intensity/low-frequency sound and infrasound are powerful forces, and governments have tested and used them as a weapon of war.
For example:
A.) "Acoustic Bullets. High power, very low frequency waves emitted from one to two meter antenna dishes. Results in blunt object trauma from waves generated in front of the target. Effects range from discomfort to death. A Russian device that can propel a 10-herz sonic bullet the size of a baseball hundreds of yards is thought to exist. Proposed fixed site defense. Also known as sonic bullets." (Source - Glossary of Non-lethal weapons Terms, edited by Robert Bunker)
B.) "Acoustic, Infrasound. Very low-frequency sound, which can travel long distances and easily penetrate most buildings and vehicles. Transmission of long wavelength sound creates biophysical effects; nausea, loss of bowels, disorientation, vomiting, potential internal organ damage or death may occur. Superior to ultrasound because it is 'in band,' meaning that it does not lose its properties when it changes mediums such as from air to tissue. By 1972, an infrasound generator had been built in France that generated waves at 7 hertz. When activated, it made the people in range sick for hours." (Source - Glossary of Non-lethal weapons Terms, edited by Robert Bunker)
C.) "And for thirty years already there have been experiments with infrasonic radiation weapons, with at least two experimenters suffering severe injuries (the Hungarian government reported that 'calculations have shown that the destruction of human beings would require considerably less expenditure by infrasound weapons than by any existing type of weapon of mass destruction.')" (Source - New Armageddon Weapons)
D.) "Acoustics. Intense, high power sound energy (in the ultra, audible, or infrasound ranges) that can cause disorientation, nausea, and extreme discomfort. May be potentially lethal. Not yet a mature technology." (Source - Does Israel Have Non-lethal Options?, Updates from AIJAC)
E.) "For example, infrasound generators, designed initially for crowd control, emit very low frequency sound waves that can be tuned to cause disorientation, nausea, and loss of bowel control." (Source - LOOKING AT PEACE EDUCATION, by Roger Walters
F.) "Today, the US Department of Defense is testing acoustic rifles that can stun and even kill solders." (Source - Feel the Noise, by Jack Boulware)
G.) "During World War II, Nazi engineers prototyped a revolutionary sonic 'cannon,' which fired a shock wave strong enough to bring down a plane." (Source - Feel the Noise, by Jack Boulware)
H.) Amplified music, such as Metallica, Sesame Street, and Barney tunes were used by the U.S. government in 2003 to break the will of Iraqi captives. The goal was sleep deprivation and playing music culturally offensive to the listener. Amnesty International objected to these tactics, saying it "may constitute torture - and coalition forces could be in breach of the Geneva Convention." (Source - BBC News, Sesame Street Breaks Iraqi POWs, 5/20/2003)
I.) "Recently, psycho-acoustic warfare was allegedly used in the Waco siege at the Davidian compound in Texas, where it is said that the FBI used sounds of babies crying, dentist drills, and a variety of other unpleasant sounds to mentally influence their opponents. The Waco compound was allegedly bombarded for long durations by these sounds via large public address systems. Although this type of sonic assault can have a profound emotive effect on individuals, it relies heavily on the individual's particular experiences." (Source - Acoustic Trauma: Bioeffects of Sound, by Alex Davies)
J.) The Nazis, in WW II, used the same type of sound like boom car owners are using today! Hitler conducted noise experiments on prisoners and actually tortured them with high-intensity/low-frequency noise. In WW II, the Nazis didn't have the technology of powerful amplifiers that we do today. So, they developed a weapon that produced high intensity sound powered by "compressed air."
K.) Unbelievably, the U.S. armed forces are starting to produce their own boom cars! They are trying to interest and recruit young males. One of these vehicles is a Humvee called "Mountain Thunder," and is used by the West Virginia Army National Guard. At least 10 states have ordered similar vehicles. The conversion of each Humvee is about $25,000.00. Major Ron Garton commented on the Humvee and the current need for them in the war against terrorism in Iraq, "We've got a severe shortage of Humvees. We really needed to throw this one back into the inventory. They're a hot item right now." Had it been shipped with its sound system intact, Major Garton joked, "It could have had some psychological-operations possibilities." (Source - A Hummer of a Humvee, by Rick Steelhammer; Sunday Gazetter Mail Online, 3/2/2003)
L.) Operation Just Cause was launched on 12/20/1989 by U.S. troops. It was against Manuel Noriega in Panama. On 12/24/1989, Noriega had barricaded himself in the Vatican Embassy in Panama City. To flush him out, U.S. troops bombarded the Embassy building with "blaring rock and roll music (The Animals, Bobby Fuller, Bruce Springsteen) around the clock for several days." Noriega was forced out by January 4th. (Source - The Growley, May 2003, Essays by Michael Gilleland, Musical Torture)
M.) The prison system uses loud, amplified music to lower the morale of prisoners and prevent conversation by piping in "heavy metal or rap" from morning until night. Even the guards have to "bellow to be heard." (source - Noise as a Metaphor for Koyaanisqats!, by Maya Khankhoje)