I don't use subs,my speakers go down to 30Hz nicely plus my room mode there I'm ok.
However I have tested 4 of 5 pair of subs (only pairs in this house
) and even I live in a detached house and the listening room is 4 meters down the earth with 70cm reinforced steel concrete when cranked up was well audible around the house (the yard ) and I'm sure was audible to the houses next to me even if they are at least 20 meters apart.
OK,I'm talking loud,it was just a test but I'm sure people would be bothered.
Just think of this cars with the subs that's well audible long before you see them.
Difficult subject...