I actually called up and talked to Centerpointe support a few times about this very question, as well as LS support. Based on what they all said, and my experience (albeit, somewhat limited, although I did go up to Awakening Level 1 with Holosync), is that there is little problem using noise canceling technology for the very beginning levels of Holosync and no problem for Paraliminals (the most important part of Paraliminals is not the Holosync tech anyway. It is the Paraliminal tech, the multiple voices in stereo).
And for those who still want to avoid noise canceling tech, here's another (somewhat cumbersome, but still effective) for eliminating noise: use the kind of ear protection that people use for shooting guns. You can find these in many different kinds of sporting goods stores. They go over the ears like traditional ear phones. You can use ear buds for your audio connection and then these ear protection things will block out a lot of sound. They are heavy and usually have a metal piece in the head piece. But they do eliminate a lot of noise from the outside.
