Sonic weapons frequently occur in science fiction and fantasy. I remember reading the Tintin book The Calculus affair, where Professor Calculus invents ultrasonic devices which break glass objects around the house. But the bad guys from Borduria want to make them large scale and long range devices, capable of mass destruction.
As with many fantastic fiction ideas, sonic weapons have a firm basis in fact. But one of the first planned uses for sonic devices in war was as a defense system, not a weapon.
Between about 1916 and 1936, acoustic mirrors were built and tested around the coast of England. The idea is that they could reflect, and in some cases focus, the sound of incoming enemy aircraft. Microphones could be placed at the foci of the reflectors, giving listeners a means of early detection. The mirrors were usually parabolic or spherical in shape detect the aircraft, and for the spherical designs, the microphone could be moved as a means of identifying the direction of arrival.
It was a good idea at first, but air speed of bombers and fighters improved so much over that time period that it would only give a few minutes extra warning. And then the technology became completely obsolete with the invention of radar, though that also meant that the effort into planning a network of detectors along the coast was not wasted.
The British weren’t the only ones attempting to use sound for aircraft detection between the world wars. The Japanese had mobile acoustic locators known as ‘war tubas,’ Dutch had personal horns and personal parabolas, the Czechs used a four-horn acoustic locator to detect height as well as horizontal direction, and the French physicist Jean-Baptiste Perrin designed the télésitemètre, which in a field full of unusual designs, still managed to distinguish itself by having 36 small hexagonal horns. Perrin though, is better known for his Nobel prize winning work on Brownian motion that finally confirmed the atomic theory of matter. Other well-known contributors to the field include the Austrian born ethnomusicologist Erich Moritz von Hornbo and renowned psychologist Max Wertheimer. Together, they developed the sound directional locator known as the Wertbostel, which was believed to have been commercialised during the 30s.
There are wonderful photos of these devices, most of which can be found here , but I couldn’t resist including at least a couple,
a German acoustic & optical locating apparatus, and a Japanese war tuba.
and a Japanese war tuba.
But these acoustic mirrors and related systems were all intended for defense. During World War II, German scientists worked on sonic weapons under the supervision of Albert Speer. They developed an acoustic cannon that was intended to send a deafening, focused beam of sound, magnified by parabolic reflector dishes. Research was discontinued however, since initial efforts were not successful, nor was it likely to be effective in practical situations.
Devices capable of producing especially loud sounds, often focused in a given direction or over a particular frequency range, have found quite a few uses as weapons of some kind. A long-range acoustic device was used to deter pirates who attempted to attack a cruise ship, for instance, and sonic devices emitting high frequencies that might be heard by teenagers but unlikely to be heard by adults have been deployed in city centres to prevent youth from congregating. However, such stories make for interesting reading, but it’s hard to say how effective they actually are.
And there are even sonic weapons occurring in nature.
The snapping shrimp has a claw which shoots a jet of water, which in turn generates a cavitation bubble. The bubble bursts with a snap reaching around 190 decibels. Its loud enough to kill or stun small sea creatures, who then become its prey.