DBDRAGGUY
10+ year member
CarAudio.com Veteran
Save the box, and build another. A easier solution would be to cover the port, and add some scrap mdf to the inside of the enclosure to displace the extra cubes. I did something similiar a few years back by adding some small boxes to the inside of a large enclosure to manipulate the tuning frequency without hacking up a 15 cube enclosure.