Port Size

I just purchased two 08' Memphis M3 12's and want to build an spl enclosure. Memphis says the optimal enclosure for two 12's ported is 4.5 cu.Ft.. But the port is only 36 Sq inchs for the two 12's. Any suggestions on port size? This port seems a little small to pull #'s

check this site it will tell you how to calculate your port shttp://www.bcae1.com/spboxnew2.htmize

Hey this site doesn't come up?.

try
http://www.bcae1.com/spboxnew2.htm