Neighbours children driving me mad!

[tooki]

When I was a kid I wanted t invent a lawn mower with speakers that produce the noise of it 180' out of phase. Assuming you have a lawn mower that made a single frequency sinewave this would not work? It would be double loud or silent as you moved around? I remember hooking up speakers in reverse and it made strange effects lowing the sound quality when they were placed in opposite corners not silence.

You need to get another set of neighbors with children 180's out of phase with the problem kids problem solved.

Volvo did just that in some cars, like the V50 with 5-cylinder engine! (Maybe they still do, and maybe other brands do, too. I dunno.)