Does anyone know how port placement effects the frequency responce of the subwoofer?

I was planing on building a new box for my 2 Kaption audio SRX 12s. The box is around 4.5 cubic feet and the area is around 72 sq.in, the length is around 30 inches. For now the plan is to have the subs and port on the same side with the port being L shaped and goining against half of the back wall. The subs and box are not public yet so I cannot link the m in this question. Anyways, I was wondering if having the port in a diffrent orientation would help sound quiality or SPL in any way.

The tuning frequency of the port is very important.  Its good to tune port near the resonate frequency cuz thats when the most air will be moving in the port. Once you get below that frequency your Db will start dropping quick because your losing box pressure.