For me: definitely. The sounds are constantly changing, so I'd notice the oddities in a few hours at most
yes, but if we truly emerged as blank slates, then we might just see the sound as "normal" I know a couple people who have had relatively loud tinnitus for longer than they can remember and because it was integrated into their sensory landscape at that level, it's just 'normal' to them.
Yet some people who are born with it struggle with it. It appears we’re not designed to have that level of intrusion.
We would definitely still have tinnitus because it results from any kind of damage/dysfunction somewhere in the body. If it were a memory thing, then anyone who has ever had tinnitus would have it forever and that obviously isn't the case - talking about people who have it for a few hours after a loud event or people who have it from an infection and for who it goes away after say, two months as the infection clears up. However, if we didn't know any better then we would interpret this as silence. Not quite the same, though.
