I only felt it fair that if the 47 is being dismissed on measurement alone (since none of us seem to have A/B'd these two monitors) that I should give a bit of criticism of the 310 based on measurements.
Sure the 310s have never struck me as lacking bass on the occasions I've heard them, and of course, the LF region is so influenced by room placement / wall proximity that a few dB here or there in basic FR is almost irrelevant.
But I'll argue it because, internet, and even if I'm wrong that's what we do, right!?
I can say for a fact that on Amir's on-axis FR plots, everything below about 120Hz is around 96-97dB and everything above 2k is more like 98-100dB. So it's not nothing.
The 47 is scrappier, but less tilted, to my eye.
FWIW, I've heard the 310 in a couple of very small rooms (14x10' maybe?) with little treatment and slightly larger rooms with what seemed like good treatment (22x16' maybe?) and they sounded pretty great in all setups!
Exactly like others have said, in the larger room it was a bit easier than I'd hoped to get them sounding stressed in their bottom octave. Not that bass overall didn't go loud, or deep, but that (like any speaker) it can't do both at the same time.
(I don't know if it has a DSP push to extend the LF cutoff at the expense of SPL maybe? Or maybe I'm just getting used to monitors where the LF that would trouble them is high-passed out these days.)
I do think in a 14x12 room you will be OK with typical material at 85dB, especially if you anticipate knocking the LF down for boundary reinforcement.
