I just went and bought these two microphones:
the logitech one was an open-box special at best buy, $16.99 so I got it even though I had JUST bought the labtec one at walmart for about $9. I'll see what I can figure out with them. Obviously i've just thrown my pipe dream of saving money by "upgrading" a cheap mic, but oh well. I'm just too curious
I did get some info from a person who's heavily into electronics and audio, and has a lot of experience with expensive noise cancelling mics, and he said that the noise-cancelling effect is actually largely due to the vents BEHIND the microphone... apparently any noise entering from the front will be picked up, but any environmental noise gets cancelled because it appears on both the front, and the vents in the back... I will have to try covering up the vents and see if it makes a difference. If that does turn out to be the case, then any of you who take your microphone apart and mount the element somewhere are essentially losing the noise-cancelling effect...