Gochurchgo wrote: "I guess I’m assuming floor standing speakers will project bass through the floor to the neighbor below. I’ve been operating on the presumption that stand mount is the imperative."
Bass can be transmitted by two mechanisms: Airborne vibrations and mechanical vibrations. The latter can be largely prevented by placing the speakers on de-coupling devices or pads, such as the Auralex SubDude. The only way to prevent airborne vibrations is to not generate them in the first place.
Gochurch again: "I just don't want to (and probably cannot) run a sub in apartment life."
One imo worthwhile advantage of running a sub is the adjustability. You don't have to run it at full power (relative to the main speakers). You can turn it down or turn it off. And with two subs and a phase control you can increase the sense of envelopment while not adding a whole lot of bass energy (I can describe how if you would like). Again, use something like the Auralex SubDude underneath the sub(s) to largely eliminate structure-borne mechanical vibrations.
Gochurchgo: "I try to use Napalm Death (the band) as a guide as its crazy heavy and super fast. If the speaker can render all the layers and keep the speed, it will probably work."
This makes me think you might want to consider fairly narrow-dispersion speakers. Here's why: Reflections in the room, and in particular the earliest reflections, constitute a "noise floor" which partially masks and therefore degrades the clarity of subsequent sounds. Speakers that put less energy into the reflections for a given sound pressure level at the listening position will have a lower in-room noise floor and therefore better clarity, all else being equal. Not saying that ALL reflections are bad; just that for very fast and complex music in a smallish space, we might want to be closer to that end of the spectrum.
Go, church. Go!
Duke
speaker designer dude guy