Carver Model 2866 Boattest Anybody Know About Carver Sub-Woofers?

Anybody know about Carver Sub-Woofers? - carver model 2866 boattest

I bought an open box, subwoofer by Bob Carver a few years ago operated. I think it is 400 W and 10 inches. Pattern. Two questions.
1] What is the bass player to tip?
2] What is the difference between being "in phase" or "backstage" is a sub?