ok i posted this on another spot on this fourm but i think i might have put it in the wrong spot....im building a box (hopefully my btl will be here soon) im going with sub up and port back....i was wondering if its would be best to put the sub over the port or closer to the front of the box or just in the center

is this a pure SPL box?

This is vehicle and install dependent. Some installs require the driver and port be located in certain areas. For SPL comps, driver and port placement maybe more critical to squeeze every tenth out of the meter.

If possible, I like to place the driver as close to the port opening (on the outside of the enclosure) as possible. I never had an issue where the port area was that large that the driver unloaded. This normally helps keep the driver away from the port opening inside the enclosure as well.

well im not gonna go to any competition i might hook it up to a meter just to see what it will do (there isnt anybody around here who has a term lab) but im going for loud and a wow factor....i used to have a 12'' btl n2 and i got rear ended and it tore the sub up pretty bad....and that was sub up and port up...but now im going for more i might add another 15 after christmas ,but one one will have to do for now...but im gonna put the port across the bottom i just wasnt sure if the sub placement was very crucial...i didnt want the sub to unload and have to build a bunch of boxes to figure it out....thats why i came to the pros