That's not lined or anything by the way. Here I'll give port type a try. Need someone who knows what they are talking about to check me though.
Useful stuff:
XMAX = 11.91 mm
FB = 27.66 Hz
So for a round port:
Minimum Round Port Diameter: 8.21 in.
Minimum Round Port Area: 52.94 in.
If you want square:
7.28 in. is for a side of a square diameter.
You need to tell us if you want round or square ports, how many ports you are going to have, and what diameter/size so I can calculate the vent length.
