Why is it so easy to tell the difference between live and recorded music?

Some of Frank Zappa's stuff is very hard to tell if it is live or not. Mostly very well done.

Frank Zappa’s entire catalogue or most of it has one outstanding characteristic. Dynamic range. The Official Dynamic Range Database. Check it out.

I posted about this a while ago.  To my ears, there is very rarely a doubt.  Sight unseen, approaching an area where music is being played, without prior knowledge, I can very reliably tell if "it's live or if it's Memorex";-)

I've always thought that, on a subconscious level, your brain goes down its "survival checklist" when it encounters new sounds. One of the questions it asks: Is what I'm hearing able to cause physical harm? Is it real? Is it close? Etc. A marching band passing your open window leaves no doubt as to its potential for physical harm. Any stereo you are likely hear just won't have the same cues.   

I’m in the same boat as Trelja , natural tone and timbre seem the limiting factor for many systems/components. This is the bottleneck more so than dynamic range which is the next most limiting factor IMHO. The addition of a certain hardness or "edge" signature just labels the sound artificial or canned more often than not. These are the two main culprits but there’re others that exist.
Charles