Almost a port mistake

[bassface]

Just wanted to bring up a mistake I almost made when calculating the port area. For example if the specs call for a 12" round port that is 23.5" long, you cannot just say Ill use two 6" round ports the same length because a 6" port is only 1/4 the size of a 12" round port in square inches. It would take four 6" round ports to equal the size of one 12" round port. So I just wanted to bring this up because if I almost made this mistake im sure someone else has also.