What makes speaker's sound big?


Does a speaker need to have many drivers or a large driver area to sound big and fill the room?
I am asking this question because I have a pair of tekton design double impact and would like to replace them with smaller speakers and a pair of subwoofer's to better integrate the bass into my room.
I just borrowed a set of B&W 702S. The are good but the just don't make that floor to ceiling sound that I like.
Maybe I have already answered my own question (: But again I have not heard all the speakers out there.
My room measure 15x19' and the ceiling goes from 7.5 to 12.8'

martin-andersen
Hello . Horn loaded speakers. Very sensitive doesn't take a lot of wattage to get them singing.  I don't work for jbl but they have quite a few speakers with compression drivers and decent woofers that not only fill your room up but will have strong deep BASS. or you can do some research and build your own set of speskers
I asked the DIY audio community here in UK about room filing, all absorbing sound and the consensus was basically “big boxes, and the biggest box is your room so use it”.  Hence the 6 foot high backloaded horns that now grace the end of my living room.  In my son’s smaller space his 9x2 line arrays plus subs sound great - and sound great if you are sat on the futon, or bopping about. 
This is a not so well defined criteria. Some call the soundstage size an expression of BIG sound and some consider bass extension the criteria for BIG sound.
 A truly big soundstage comes from speakers with very low distortion artifacts and minimal diffraction effects. Diffraction and distortion effects are non consonant and detract from the soundstage scale. Low distortion bass extension is well understood.