Although there are subtle differences in musical performances that are played from "written" scores (i.e. most classical performances, as well as dance bands playing from music) It is only in more recent decades that the majority of musicians "made it up as they went," meaning that any recorded performance can be musically specific.
It's like the difference in identifying alternate takes of a dance band playing from a "stock" and, say, Duke Ellington...
Mike -- mrichter@xxxxxxx http://www.mrichter.com/