unforum

Seej · Unfettered Joined: 30 Nov 2004 Posts: 614

Mmmm, I got the impression this was a less-cerebral sport than the rest of the PPC games - something a bit more physical and silly.

As far as active noise cancellation goes, you can invert a waveform and play it back alongside the original wave and if they're both going into your ears at the same time they perfectly cancel each other out - this is how the Bose headphones work, and I understand there's some airline seats that do the same thing.

The only problem is that the waves have to be in perfect antiphase to do this - anything else reduces the effect. This is only possible when the location of the sound sources can be controlled, which is why it only works practically with headphones and in seats where your head is gonna in the middle of the speakers.

The real problem with doing something like this on a larger scale is that the phase difference depends on how far you are from each wave source - if you put two good loudspeakers a metre or so apart, have one playing the inverse of the other, and walk from side to side in front of them you'll hear the sound getting louder and quieter as you pass through points of constructive and destructive interference (maxima and minima). At the points of constructive interference the sound you hear will be louder than the sound coming out of each individual speaker.

Therefore, I'd guess the noise-supression will be a passive device like a really big piece of foam or something....

*bows, then takes off physics hat*