Here is my sub setup. Not nearly as current as most but sounds good to me.
Pic-1: Screen wall w/ DIY built in sub on left corner
Pic-2: Closer shot of DIY sub enclosure
Pic-3: JBL Synthesis-1 sub (Oldie but goodie)
Pic-4: Business end - sub powered by Crown K2 bridged mono + FBD for active EQ