Originally Posted by miniSQ View Post
exactly, you need to make sure when making your 2.5cft box that you add to the overall size the amount of space the port will consume. so its 2.5 PLUS port volume when building.

Have you considered doing a slot port?
A slot port will still be taking up volume, and often the slots have more area than a round port... hence sloted ports gobble is more volume than a cylindrical port. There are only two solutions that gobble up no volume.