Originally Posted by GusinCA
At one point I heard some company was making a helmet that had active noise cancellation built into it (which would really reduce road and engine noise, but still allow the rider to hear sirens and such). Anyone know about this or know if it's been done? I've searched and can't find anything. Maybe I'll build a helmet with noise cancelling headphones built into it or something. I hate earplugs and I hate noise. :)
Noise cancellation, or insulation.
Insulation is possible, cancellation is impossible with a static physical system.