Live music cannot act as a reference; the bands have very little control over the sound, so what you get most of the times is a typically laughable PA system combined with the acoustics of the venue. Even worse, if you prefer standing in the first few rows, you are usually behind the plane of the speakers, so all you get is the sound of the band's equipment, plus reflected sound.
Many of the audiophiles I know only listen to classical or other acoustic music. I'm never sure if their musical tastes run that way, if they feel it's easier to tell if they're getting an accurate reproduction or if there is just a layer of snobbery running the show.
I do think it's easier to get a sense of realism (or lack thereof) from acoustic instruments, though comparing a live performance to a recording will always be sort of pointless, as the recorded performance is but a moment in time, with a unique combination of acoustics, temperature, instruments, instrument condition and the performance itself.
With amplified music, you get other variables. The guitar amps used in the studio are seldom the ones used live. Mic placement will always vary. Live sound is often not in stereo. Since the point of a guitar amp is to alter the tone, it's hard to say when you have an accurate rendering. Most of us can tell if it's in the ballpark but it might take Fourier analysis to tell if the reproduction is faithful.
With rock music, it's quite a bit harder to determine realism, though I notice that whenever I'm out and hear music coming from a club, I can always tell whether it's live or recorded, even from outside. I think it's primarily the dynamics. Recorded material
never has the same dynamics.
