Technically the 901s can be run "in reverse" depending on the conditions and desired results. Additionally, the 801s/802s only have 8 FORWARD FACING drivers.
Our church had these all over the place but they had the full length bass cannons, our bose rep definitely loved us. I don't remember that impressive of bass coming out of what I imagine is a 10" woofer in a 1/4 wave transmission line enclosure. They later upgraded to Yorkville elite and danley systems that were miles better. According to the Bose spec sheet, these produce a max of 109db which is an abomination for a PA sub and pretty lousy even for a home theater sub
Oh, it's legendary AWCS-II SR model!!! 43 Hz resonance👍🏻 I would also like to add AWCS-II to it for complete happiness with 25 Hz!! No one else will give such a true bass😃