box sizing

Hello, i'm sorry for my bad english! I just bought new alpine swr12d4 sub, i find some sub box and put sub in it. But those volume is more than recommended(1.25-1.50 cu. ft.). This box volume is about 2.1cu.ft,. Photo: http://www.bildites.lv/images/562lqre3ijf46w8i3hc.jpg So, what do you...

I have a custom fox acoustics box. Its 2 X 12 ported, with a vent tune frequency of 35 Hz. The box is divided and each side has an air volume of 1.55 feet. This limitation is preventing me from obtaining certain subs I would consider better. so my question is: What is the maximum port box...