Likewise, some sources for audio damage from noise canceling would be great. I wear headphones 8+ hours a day for work. Around two months ago I upgraded my 10-year-old (cheap, wired) Sennheisers to some mid-range wireless ones with noise canceling, they're a bit heavier but otherwise just as comfortable and noise canceling is awesome for helping me focus. I've never had any negative effects from either (although I'm careful to keep the volume down).