Crossovers aren't a brick wall, so frequencies above the crossover will still be heard, they should be at a reduced volume, however you may have a peak above your crossover so the room is effecting the crossover slope.
^^^ Actual numbers depend upon the crossover design, of course. That said, an excellent plot to illustrate hoe sound does not immediately die way on either side of the crossover. This is also why getting the subs in phase with the mains at the crossover frequency is important to prevent cancellation of sound.
"After silence, that which best expresses the inexpressible, is music" - Aldous Huxley