My first experience with subs was memorable. I got a used pair of Vandersteen 4’s, large 4-way speakers with a powerful integrated sub built into the base of each speaker. Each sub (located in its own enclosure with a slotted port) consisted of 2 x 12" metal cone woofers linked together with a steel bar. That design produced the best bass I ever heard from floorstanders. And FWIW, I would never have a modern ported sub in my system now, but those Vandy ported subs sounded incredibly musical.
Years later my audio system is desktop, all crammed into a 13’ x 13’ home office; the speakers are nearfield. I’ve learned to go with all sealed/acoustic suspension speakers & subs here. I can only fit 1 sub: currently it’s the excellent JL Audio e110, a powerful 10" design. The mains are vintage KEF 103.2s, 2-ways with a strong low end courtesy of the 8" woofers. I have the sub crossed over slightly above where the mains start dropping off. It sounds like one big pair of speakers.
I’d never want to be without a sub...