Anybody have experience with "Janis sub woofers"

I have had a pair of powered 12" Janis subs in my dedicated two channel system for 20 years. The embarrassing truth is I don't really understand them,(never did) They each have a crossover /100 watt amp. They are crossed over at 100Hz and are are set up and in use for Right and left Channel connection. They where built in New York City by a company called John Marovski Audio. The instructional manual that came with them makes me dizzy,(it doesn't take much)It talks about, and offers settings for phase correctness etc. I can hear a change when I switch them off, but I don't know if I'm getting the most out of them. I would appreciate any council offered.