could be.... did a course for sound engineer, but didnt like the music biz, but still love sound... human hearing is a very funny thing, part mechanical, part electrical impulse, with some rather sophisticted processing going on in.that if you listen to a concert piano bieng played back on an ancient taped deck.with a 1 7/8” speaker, that speaker is incapable of reproducing the low c, but you will hear it, because you can hear the harmonics of that low c, and your brain fills in the "obvious" fundamental tone. which means that we are always "hearing things":) other wierd stuff, like going into an anekoic chamber, and sitting quietly, of which I have not done, but is apparently rather odd. so it is possible that "noise cancelling" which is just enough processing to create a sound wave 180°out of phase to the "noise", could be messing with peoples brains, as it trys to out process the very unnatural digital processing.