The noise cancelling part was particularly fascinating. Not only was it ineffective, it amplified the sound. I think its because noise cancelling circuitry relies on the ability to create a signal frequency that cancels out the initial waveform. That’s all well and good, but I think the sound cannons use separate speakers out of phase. Since the noise cancelling headphones produce a signal in phase with the first frequency detected, the microsecond slight delay causes it to be added to a subsequent phase boosting the power.