Unless your floor is concrete, I would think isolating your subwoofer would be better. With standard wood frame construction, you don’t want the sub to couple to the floor which then acts like a radiator vibrating at its resonance frequency, mucking up sound quality. When I isolated my subwoofer from the floor, sound quality went way up. I noticed that it didn’t interact with the room as much - much less vibration coming thru the floor. If your goal was maximum loudness and impact, maybe you want that effect, but you don’t where sound quality is the objective.
Does a Subwoofer Make Spiking Redundant?
I just added a REL T5/x to my system, and a question rises up from the depths of my ignorance: Does a subwoofer do the thing spiking speakers is supposed to do? Does a subwoofer make spikes redundant, or do they work at cross-purposes? If it's relevant, I've got the spikes on Herbie's Audio Lab puckies, on a (thinly) carpeted floor.