Basically what I want to do is sample an incomming waveformm, generate the inverse and blast it out of a pair of headphones, cancelling out the original sound.
I'm interested to see if it will produce a 'silencing' effect, as physics dictates it should. If so, then I can mix in other sounds without background interference, hopefully distracting the gamer less.

A quick look in the directX7 API reveals nothing in the way of manipulating the waveform stored in a buffer, so am I going to have to do nasty low level stuff? Has this been tried before? Any comments please!!