I'm not entirely sure what you mean by "big sound" so I'm going to assume you mean a dimensionally large soundstage.
I agree with Sogood, larger speakers aren't necessarily going to help you at all, except that some panel speakers and line stages do present a taller image than the point source dynamics (and Quads).
What I have observed is that some dynamics (including my speakers which are based on Dynaudio drivers) like a fair amount of power to open up. Run at quiet to medium volumes the image is rather compressed, but at higher volumes they are very expansive and fortunately undistored because this is my preferred way of listening to them. Some other dynamics that I have listened to seem to open up at much lower volumes (but there are other tradeoff's) as do horns and some electrostats (including my Quads which you can never play loud!)
In my view it is more about the speakers design than size and how well you can accomodate them in your room. The acoustic problems that your room presents in the bass will be pretty much the same for most full range speakers.
In my room which is not much larger than yours, but with taller ceilings, I have noted one exception - full range panel speakers and dynamic's with upper bass/midrange woofers 3&1/2 to 4 (or higher feet off the floor seem to excite room resonance at 160 to 200 hz This hump doesn't exist at all with my Quads or my main dynamics in which the bass is crossed over at 400hz, so I suspect that the heighth of the driver producing sounds in this zone are exciting those frequencies. Interestingly with panels it was 16db, with the dynamics its 5db. With the Quads and Dyna's it was 0 dbs.
So in my view bigger speakers don't necessarily produce bigger sounds, nor do they necessarily produce bigger problems. The issue is speaker design and room/system integration.
I agree with Sogood, larger speakers aren't necessarily going to help you at all, except that some panel speakers and line stages do present a taller image than the point source dynamics (and Quads).
What I have observed is that some dynamics (including my speakers which are based on Dynaudio drivers) like a fair amount of power to open up. Run at quiet to medium volumes the image is rather compressed, but at higher volumes they are very expansive and fortunately undistored because this is my preferred way of listening to them. Some other dynamics that I have listened to seem to open up at much lower volumes (but there are other tradeoff's) as do horns and some electrostats (including my Quads which you can never play loud!)
In my view it is more about the speakers design than size and how well you can accomodate them in your room. The acoustic problems that your room presents in the bass will be pretty much the same for most full range speakers.
In my room which is not much larger than yours, but with taller ceilings, I have noted one exception - full range panel speakers and dynamic's with upper bass/midrange woofers 3&1/2 to 4 (or higher feet off the floor seem to excite room resonance at 160 to 200 hz This hump doesn't exist at all with my Quads or my main dynamics in which the bass is crossed over at 400hz, so I suspect that the heighth of the driver producing sounds in this zone are exciting those frequencies. Interestingly with panels it was 16db, with the dynamics its 5db. With the Quads and Dyna's it was 0 dbs.
So in my view bigger speakers don't necessarily produce bigger sounds, nor do they necessarily produce bigger problems. The issue is speaker design and room/system integration.