Two medium size woofers Vs One big size woofer

Thanks you all for your comments.
I currently have a pair of 3-way Sonus Fabers (one tweeter, one midrange and two 7 inches woofers). So I've looking into a new pair of speakers that could keep up with the space (1000 Sqft former factory loft, 13ft height ceilings, open space, no walls). *Room has some minimal treatment.
Aesthetics are somehow important, so that's why I've considering thinner towers over boxy (JBL type speakers).

the key specification is a thing called acceleration factor.

the smaller driver has a larger acceleration factor.

two smaller drivers with the same swept area as a single larger driver..the two smaller ones (~7") will create a notably more articulate bass and have better integration with say, a electrostatic panel- vs that of lets say..a single 10".

eg:

www.audiotechnology.dk

C-Quenze 15 H 52 06 13 SD (5")
Acceleration factor: 674
C-Quenze 18 H 52 17 06 SD (7")

Acceleration factor: 499

C-Quenze 23 I 52 20 06 SD (9")

Acceleration factor: 423

So you get more cheap thump with the larger single driver, but you don’t get articulation. Articulation requires a high acceleration factor. Which is generally with smaller drivers, due to lower mass smaller cones.

IIRC, a tweeter runs near 1000, or just above it, maybe. Thus the 674 of the audio technology driver is crazy fast. This is a difficult spec to find as many driver manufacturers might be embarrassed to print it.

Great, if that's the case, I get good sound along with aesthetics.

There's no substitute for surface area and maximum linear displacement in absolute terms. The idea of small drivers being faster is rarely proven.  Two 8" drivers have about the surface area of a single 10" driver but often with lower impedance.  It's not like you get a 16" driver by buying 2x 8". Also, the 8" drivers tend to have shorter displacements and power handling, so assuming they had the equivalent surface area of a 16" (and they don't) they'd never have the same linear movement capability.

Having said this, I will say I'm a big fan of 2.5 way systems for their efficiency and foot print, but they do tend to have lower impedance with the parallel drivers which can make them underperform with less capable amps.

The big issue in terms of having "fast articular bass" tends to be that the lower you go, the more issues you run into in a room. A speaker that is anechoically flat to 16 Hz may sound really crappy vs. a smaller speaker which is flat to 40 Hz as the big speaker will aggravate the room modes more.  

There's a big difference between the anechoic bass response of a speaker, or the -3 dB point, and how it will sound in a room. Smaller is often better. 

two 5" woofers is equivalent one 7" woofer , not 10"
this is simple , check any speaker design book