Ah! I meant the sweet spot for volume, not seating. Since I have to modify things a bit to fit the available space and materials, I'm making the cabinet deeper to maintain the volume and I'm wondering how precise I need to be.
And another question -- Since I need to make things a little narrower, do you have any suggestions where to find that space? You said I should protect the area around the center driver. If I make the ports overlap from the baffle to the face frame and extend the box behind, it looks dumb. Can they move to the ends or maybe the bottom (it's open below) instead of the front? Can I crowd the outer drivers together at all? It's not a big problem to tear out two more drawers if that's what I need to do. But I'm at 32" with the face frame, so most of that space will be wasted and I'll need to figure out how to make it attractive.