Is a 10-inch sub big enough?

[NoMSG]

I posted below about a choice between two 10-inch subs.

But then I thought, "Is a 10 incher big enough?"

The entertainment room is 13 x 20 with a typical 8-foot ceiling. The weird thing is that along one of the 20 foot walls is a 6-foot wide archway that connects that room to a slightly larger room.

So, will a 10-inch sub like the SVS PB-10, be sufficient for HT?