just my lay person thought here.

But if you could cancel the noise/signal perfectly and everywhere wouldn't that sorta violate energy conservation?

The sound energy has to go somewhere right?

loa_in_ 4 days ago | parent | next [-]

You are providing the energy by emitting the counter signal in the first place.

card_zero 4 days ago | parent | prev | next [-]

That's an interesting question: what to do with the energy, ideally? Maybe convert it to very low frequency, so it only annoys elephants.

Perfectly? Surely that is not reasonable?

	▲	IAmBroom 3 days ago \| parent [-]
		Even imperfectly, the problem remains - and is answered by the "the energy of the cancellation source counterbalances the noise energy."