How do you calculate two ports

Chad Lee Silver Member Username: Bestmankind Los Angeles, CA USA Post Number: 129 Registered: Oct-05	Posted on Thursday, November 03, 2005 - 00:37 GMT i've seen some enclosure with two port holes. how can you tune boxes to have two ports on each side.
Trevor Eaton Gold Member Username: Tdeaton1021 Near Tampa, Florida USA Post Number: 1190 Registered: Sep-04	Posted on Thursday, November 03, 2005 - 01:00 GMT ad the port area but dont add the port lenth. they should be the same length also. example. 2 2 inch ports 10 inches long would have 6.28 sqin of port are and 10 inch lenth.