In a modern world, this may prove impossible, but I'd love to live in a big, quiet city.
then how do emergency vehicles notify other cars and the neighbourhood that they're on their way? No real good answer to that.
no helicopters or planes
then how do we get traffic reports and get people to and fro'?
no clock bells or whistles (steamclocks)
quiet rail or electric trolley transportation
in the office/bus/theatre:
ringers on silent
people talking to each other only so that the recipient can hear them
no audible notification of messages sent and received (IM, email, Twitter, etc.)