they're PA subs from the 90's, they have Guass 15's which are pretty badass. any decent powerful sub will do.
when I use them live I don't even need them in my monitor (would sound like {censored} anyway) because you can definitely feel what they're doing coming out of the mains, it really adds a lot imo.
I used my Taurus pedals at a venue that has a large hall upstairs (where we were playing) and a normal size bar downstairs.
while we were sound checking, we made sure we played a song that had the Taurus pedals in it.
near the end of the song, the bartender from downstairs comes running up and yells "what the {censored} is going on", my glasses are falling off the shelves downstairs.
the Taurus pedals were shaking the building so much that the bar glasses were vibrating off the racks downstairs, a proud moment.
another way a guy could amp them would be, if your bass amp has an effects loop, you could stick a line mixer in the loop, or even a Boss LS-2 Line selector pedal and then blend the Taurus pedals with your bass.