This seems like a harmless tube. In fact, it was harmless: Jewish farmers used the first version to scare birds from crop fields. Then, somebody converted it into a crowd dispersion mechanism. And then, they discovered it could kill.
The Thunder Generator uses mixture of liquefied petroleum, cooking gas and air to create explosions, which in return generate shock waves capable of stunning people 30-100 metres away. At that range, the weapon is absolutely harmless, making people run in panic when they feel the sonic blast hitting their bodies. However, at less than 10 metres, the Thunder Generator could either cause permanent damage or kill any person.
It comes in a single-barrel configuration, but according to the manufacturer - ArmyTec - you can mount it everywhere, and combine it with other barrels to create even more powerful design. You can even mount several cannons on different places, and synchronise them so you can create a sound barrier perimeter capable of dissuading your enemies. In fact, you can even make the sonic wave to turn 90 degrees to fire around corners, all by using a curved barrel design.