I am almost finished building my box for these subs and amp. All I have left to do is install the port, glue down the baffle and screw down subs. My question is about the port. It is 6" pvc, five inches inside the box with the rest external. The next pic shows that the port is touching the front and back walls of the box. Is this okay, nothing is blocking the front of the port. The pic is just a mock up with a scrap piece of pvc but the finished product will be approximately the same. So what do you think?