Speaking of NYC, we've enjoyed some amazingly effective soundproof windows in many spaces, it seems like a thing there, but when we ask window salesmen in the Bay Area about soundproof windows like that, they kind of shrug and say " double pane is pretty much all you can do". Why can NYC do this but not SF? Or have we just not called the right store?
I have not heard of this unless its part of a recent local building code. I live in a house that was built in 1927 and partly renovated in the late 80's.