the specs of the box are L:26.75" W:13.5" H:13.5". THis includes the port, but the internal volume not including the port is equal to to just about 1.52ft^3 and if you take out .07 for the sub it comes to 1.45 which is the mtx recommended volume. The port size is 12x2x25.5 which is .35 inches under the recommeded length from the calculator. If anyone knows about enclosures could you let me know if this sounds reasonable. This is the second box ive made and most technical. eitherway its a learning experience. Again this is for a MTX thunder 7500 10inch subwoofer getting 400w rms power.