More Power or use subwoofer to boost bass for music

But since statistics is science, let’s consider the “odds “ of getting 4  or as some would say 5 objects placed in a convenient location vs. one....

having a bit of fun Ralph, you are a true warrior for the science and the music

Vandersteen = 11 bands of EQ with more cut than boost with EQ centers set on typical room nodes not typical 1/3 octave bands... some science cult thinking at work there... since 1977 and still going strong and I might add a supporter of swarm IF done correctly so as not to muck of the stereo image...

What amp did the dealer use ??????

Also IF flat frequency response in room was the only measure of bass quality why are there a plethora of bass guitars, standup bass, etc out there....?

this from a bass player of LiL reknown....

OP you are new and don’t yet understand that the answer is 4 or more subs in a forest of box’s and wires placed quasi randomly about your room.

bass is a wide topic and for most music listeners spans from 30 HZ to the power range of 200-250 HZ. You might try to recall or ask the dealer where those speakers were placed in the demo from side and back wall. IF you do have to compromise with near surface ( back and or side wall ) coupling, then GIK or another brand of broad band absorber panel or three to address reflections will help w imaging. Finally also you might need to tweak your listening position a bit. Room modes effect. Bass , especially below 120 HZ... even a few feet can matter.

there are other ways to add great subwoofers if Indeed the problem lies below 100 HZ. One has built in EQ.

and yes, swarm aka multiple subs...works if the crossover frequency is low enough and you like the clutter.