measure a little extra space, so wen finished and measuring the cubic back wit port in you shud get more cubic than it shud b....
so if the box shud be 2.5 cubic wit port in, and wen measured you get 2.8 cubic or wat it may b...all you need to do is take some glass and something dat occupies 2.8 -2.5 = .3
cubic and glass it in......
now u have ur perfect 2.5 cubic fiberglass enclosure tuned accurate enuff to ur frequency....
