As I said, if the noise is sufficiently consistent, then there probably wonβt be a problem with it. Content, though, implies something more than just background noise.
You missed my point about coffee entirely. The point is that if you take coffee, you donβt know that youβre tired, regardless of if itβs effective or not.
I am pretty certain our brains evolved to filter out friendly/known voices some tens of thousands of years (or more) ago. I feel tired sometimes before and after coffee, and often less so on coffee breaks because the real issue with coffee is that the caffeine can definitely disrupt sleep.
I understand you need consistency to not be engaged by sounds. I hope you understand that other people have other limitations, hence, again, it is your first statement I disagree with.