From reading the text, it's looks like it's not noise-canceling. You couldn't do active noise canceling in the car for several technical reasons (discussed in another unrelated thread here on the BBS).
It spectrum-analyzes the noise, then EQ's the music and adjusts the volume based on the spectrum. So certain kinds of road noise can be overcome by adjustments to the music.
Although notice which cars are selected for the system: They're the ones that need it the least because they're all quiet boats (and in once case a zip code with wheels).
Although I think mic-based realitime EQ adjustments would be a cool mod for the empeg, too, this isn't noise-canceling.