I think a 4x12 will have more bottom end
I'm gonna go out on a limb here and say that they would be the same. Stack the 2 2x12's and you should get the same sound.
If bottom end was important to you, then maybe you could get even more bottom end by not stacking the 2x12's... leave them both on the floor and you might feel more bass...
Another advantage of 2 2x12's is that you'd be able to spread them out. Put each one on opposite sides of the room and I'll bet it will sound amazing...
Thanks for the replies guys.
As I am building the cabs (alright I am having someone build them for me..) I will make them as deep and as large as I want them to.
I don't really want that big 4x12 cab unless I have to build one because of the sound.
The fact that the cabs are separete is a big advantage for sure. Did you try that trick with the floor? Does it really work?
If it does, I am getting the 212s for sure!
IF your concerned about the bottom, make one cabinet a 2 15" That should solve the bottom issue!
Another advantage of 2 2x12's is that you'd be able to spread them out. Put each one on opposite sides of the room and I'll bet it will sound amazing...