# Resonant Frequncy Interference Pattern

Imagine an area in which there are multiple high-power sound wave emitters (speakers, transducers, etc.) that are placed and tuned to destructively and constructively interfere with each other such that a radius from the emitters is an "dome" whose shell is a concentrated resonant frequency. The frequency that exists at the "shell" is capable of pulverizing or breaking up anything that moves into it. Tricky part: the center area around the emitters, and for some distance around them, does not affect anything negatively.

The question is: is the above design theoretically possible, under the assumption that there is enough power necessary to drive the emitters and as many emitters as necessary?

• A square wave is made up of a fundamental frequency and an infinite number of harmonics at decreasing amplitudes. I suggest therefore, that as well as resonance, you would also need harmonics. A square wave could be powerful indeed, like a sequence of jackhammer blows. – Justin Thyme Aug 24 '18 at 21:35

Different objects have different resonant frequencies.

http://hyperphysics.phy-astr.gsu.edu/hbase/Sound/reson.html

In sound applications, a resonant frequency is a natural frequency of vibration determined by the physical parameters of the vibrating object.

If your speakers broadcast a constant frequency, it might be the resonant frequency of some common object but not of others. You might shake a duck to bits but a crow will just hear a loud noise. You need some method to sweep through available frequencies and some way to determine when you have hit the resonant frequency of the object in question.

The other problem is that presumably in the sky, objects will be in motion. Shaking something to bits with sound involves incrementally adding energy to the object. You can only add as much energy as your sound carries. If your target duck flies through the loud zone quickly, there will not be much time to shake it.

Theoretically, probably. As you guessed the energy cost would be very high, but more importantly, in order to have anything in this dome, you would have to model the propagation of the space to an extremely high accuracy. Changes in heat, humidity, etc would probably destroy your dome and you'd just have a lot of noise. Rain or any water would probably pass right through, and also completely destroy the dome. With such an elaborate defense that could be defeated by...well a light fog, I can't see it as useful

With the above design, you could do some damage, but not enough to obliterate anything in it's path. You could consider some modifications.

Adding a high voltage capacitor (30,000 volts) would do the trick. but in order for that to become functional you would have to make the electronics of the speaker so A) The speaker releases a much louder stronger sound when all the energy is released, and B) So the circuits don't fry when you release all of the energy.

Another thing you could try to do is make a bowl shaped cone around the base and try to form the sound into a single high charge beam.