Nw that you're unconfused let me confuse you again
it really never does NED
one thing to keep in mind that different manufacturer's 10s sound different, as do 12s, as do 15s, etc. Driver design and cabinet design play a large role in the overall sound, so you can't always generalize about a particular diameter speaker sounding punchy, tubby, edgy, bassy, etc. A lot of 15s do sound tubby, but i dont think you could say that about a bag end s15-d (yeah so i like bag end - humor me all of you who are sick of me praising them -
). That particular cabinet is 18.5"x18.5"x15" and ends up being very punchy. Now, bag end takes the same speaker, puts it in a much larger cabinet, ( 18.5"x28.5"x24.5" - they call it the s15b-d, i think "b" must stand for BIG), that cabinet sounds much bassier and fuller than the small one, but isn't really tubby. I demod a beg end 1x18 once that was in an enormous cabinet. It had lots of low end, but it was one of the most articulate 18s i ever heard. When i originally heard it someone else was playing thru it and i refused to belive that it was the cabinet they were using. I was looking for the 2x10!
My aguilar gs-112 actually has more low end than my bag end 15, and gets darned close to being tubby. It really doesn't have the agressive mids that the bag end s15-d has either. So you end up with a 15 and a 12 which sound like they get switched at birth. Comparing my bag end s12-d to the 2 becomes interesting. The bag end 12 has much more aggressive mids than the 15, but not as much lows. It's actually punchier sounding and more aggressive than a lot of 10s, and even some 8s! Comparing the bag end and aguilar 12s to each other you would refuse to belive that they are both 12s if you come in with preconceived notions of what a 12 is supposed to sound like.
Comparisons with 10s yeild similar results. My old swr 410 pretty much sounded what 10s are supposed to sound like - very punchy and assertive (but not as much as bag end 12s) and the cabinet had really decent low end. The eden 210xlt i used to own was very different, it was punchy to a degree, but had a low mid bump that made it fuller sounding than my bag end 15. The bag end 210 (d10b-d) i just bought from nightbass seems to have more low end than my 15, but isnt as aggresive as my 12. But it does have a difference in tonality in the mids that the other 2 cant get.
To further complicate matters, a lot of times cabinets with multiple drivers sound different than ones by the same manufacturer with fewer of the same drivers. Go and try a 112 and 212 from either bergantino or epifani and you'll see what i mean. The bigger boxes have a lot more low end. If you can demo the swr 8x8 and 4x8 together the difference is unreal. The 8x8 has huge tubby low end, the 4x8 is a midrange monster but a little anemic. FWIW, the bag end 212 sounds pretty much the same as the 112 because they are totally isolated from each other and each chamber is identical to one 112 cab.
Finally, when you take multiple smaller cabs and use them together a lot of times they dont sound like one of them only louder. Put 2 bag end 115s or 2 bergantino 112s together and you'll notice more apparent low end than one cabinet by iteslf.
What does all this mean? Just that the overall descriptions of what different diameter drivers sound like are useful up to a point. After that, you have to go back to listening with your ears and not with your eyes. (or with spec sheets). I'm sure this really only confused you more.
But the basic idea is not to get hung up on what size speakers to get, it really comes down to how you like the way specific cabinets sound, alone and together.
I'll never go back now that I have my Schroeders 
