Originally Posted by JimmyM
Nope. Port location is 100% immaterial since the lows that come out of it are not directional.
The lows that come out are indeed non-directional, but (you allready thought there would be a "but"
) there are cases in which there is a descend amount of mid-frequencies comin' out of that tube/port. Mostly because of bad design or sometimes intentional to color the sound.
The following culprits come to mind:
-numero uno, no lining in the cabinet(in combination with a full-range driven woofer)
-2nd, bad choosen ratio of the port lenght/diameter/internal cab volume, this can cause a 1/4 standing wave inside the port that can be pretty audible(system starts to act like a transmissionline)
-3rd, port location(back/front excluded), if you have a high/long cabinet and the port is on the bottom or top, the standing wave that will occur inside the cabinet(will in most cases not happen in a 3-way system) will be pretty audible through the port. Solution is to place the port in the middle of the cab and in addition use an internal helmholz-absorber to (partially) eliminate the standing wave.
So for the OP, you should check per cabinet if there is anything more then only bass comin' out of that port.