The frequencies are low enough that they'll permeate the room either way, however, the 2nd octave (40-80Hz) might throw more noise in the direction of the firing... Don't quote me on that, but it'd make sense that a down firing sub, on the top floor apartment, would push more sound to the apartment below in the 40-80 range than a forward firing sub. for the lower octaves though, I think it's more directionally insensitive.