Sometimes background noise is desirable. A marketplace, trade show, dance club. The noise signals value, that this event is worth going to because other people are there.
Other times we seek to avoid it, like in a library, a bedroom, and in the wilderness. In these spaces we seek to be alone, or pretend that other people don't exist.
In city life some people want noise and at the other time others do not. How to offer both? Some examples from real cities:
Beijing has silence in the narrow, winding hutongs. Noise picks the shorter path from A to B on the busy main streets. Furthermore, household noise is kept inside the walled courtyards.
New York's tall, adjacent buildings create a noise barrier that leaves a silence in the shared backyards.
In San Francisco, noise rolls downhill. Climb higher if you want quiet.