Its all about the physics. In the studio you can dub and over dub, pan and fade, or double and delay to your hearts content but it will take some effort on the engineers part to recreate that massive air'ish feedback sound. Even onstage if you mic a small amp it will still sound like a small amp to the mixer. But set a mic in front of a large stack and it will sound like a large stack as it pushes volumes of air and sound towards and around the mic. Just because you point a mic at one speaker doesn't mean thats the only speaker it will pick up. My only point is small amps sound small and big amps sound big. Sounds stupid I know but I love my Peavey Classic 30 112 and the tone I get but sometimes my buddies 212 sounds so much larger even if mine is louder.