Ooh, this happened to my husband and me years ago, in our first apartment! The neighbors upstairs came and knocked on our door and demanded that we turn down the $@#! music already. We smiled sweetly and pointed to our floor, and they simply gaped. The police arrived shortly thereafter; the partiers let it be known that they were proud to have had their party put to end by neighbors 2 floors away, *it was THAT good*.