I have a 15" L7 solo-baric that I would like to make a ported box for. The cu. ft. of airspace specs for a ported box is 3 cu. ft. minimum and 6 cu ft. maximum. I was also wondering how to get the lowest or deepest bass, Would I have to make the ports in the box to compress the air before it comes out of the port, or does it depend on how many walls I use to make the port. Any useful info. will help, thanks.