On: Paris preserves its mixed society by pouring billi...

[Jensson]

You need better walls, aren't there standards that apartment walls need to be sound proof?

[bombcar → Jensson]

Remember that in the US at least, many dense buildings are incredibly old, from before soundproofing and such was really common.

Living in a 1900s building in Brooklyn is vastly different from living in a 2020 building in Manhattan.

[burntwater → bombcar]

My early 1910s Manhattan building was fantastically quiet, with very thick walls. The only noise I ever heard was floor noise directly above me, never to the sides.

I'm guessing mid-1900s to early 2000s buildings are the problematic ones.