Exactly VK.

So the higher the cross-over point from the non-LFE channels the more directional bass (moving trains, planes and automobiles) will be pushed to the sub, potentially damaging the image/acoustic.

Pure LFE effects (explosions, earthquakes, etc.) should shake the whole room and thus be directionless rather than located, therefore multiple subs are potentially a good thing for that application.

In the spirit of Spinaltap, I would like to confirm that I am not involved in the corrupt theft of a global sport.