Moving part 3

Two full nights we've spent in the new place.  And both times we could hear out neighbors fucking.  And I don't mean the occasional grunt or moan, and squeak of the bed, but the our neighbor lady screaming "Fuck me, aw yeah, oh harder!" And so forth.  We're wondering if are walls are really that thin or if they're really that loud.
Perhaps the most disturbing aspect of this, other than eventually running into them in the hall and trying not to giggle, is that they do this during the wee hours of the morn.  Like 3 or 4AM.  Either they stay up all night or get up at an obscene hour (tee-hee, double entendre).