volume vs # of subs- need advice

Ok. im trying to build a box properly, i have 2 Re se-x 12s and specs say they need/recommend 2cu ft. @33hz. My question is , is that per sub, like since i have 2 does that mean. i need a 4cu ft box? Or could i just account for sub displacement and they share 2cu ft? Thanks.

Per sub

Yes that spec is for each sub. I know people who went with 3 cuft and those things were slamming

I have a prefab currently at 1.7 cu ft and it hits good already. This is gonna b a huge box 4" port 42"x18hx14d