Infinity Sub Enclosure

Hello,

I currently have an Infinity 1010W sub in a ported enclosure in my trunk.  I am looking to place this in a sealed enclosure to save some space and possible get a cleaner sound.  I have contacted Infinity and they have assured me that the sub will work in a sealed enclosure as well, and that it needs to be about .75-1.0 cubic feet in size.  I would however like to build the box so it is a right triangle instead of a cube.  So here are my questions; first does anybody see a problem with making the sealed box a triangle instead of a cube?  Second, how big would I have to measure out for the cube, in the thought that when I cut it in half for the triangle, I will end up with 1.0 cubic feet of air in the box?  Third, does that 1.0 cubic feet of air just need to be the size of the box, or the size of the box with the speaker?

Thanks,

David