What does listening to a speaker really tell us?

Ok. I got lots of advice here from people telling me the only way to know if a speaker is right for me is to listen to it. I want a speaker that represents true fidelity. Now, I read lots of people talking about a speakers transparency. I'm assuming that they mean that the speaker does not "interpret" the original source signal in any way. But, how do they know? How does anyone know unless they were actually in the recording studio or performance hall? Isn't true that we can only comment on the RELATIVE color a speaker adds in reference to another speaker? This assumes of course that the upstream components are "perfect."
I agree that you often can't hear those details in live performance. But if you could, you'd pee your pants and declare the venue the greatest in the known universe. So why not have the detail at home if you can.
If given the choice, I'd really rather not pee in my pants, either at home, or in
a public venue. Is there a way to have a great system and avoid this? I have,
thus far, managed not to pee in my pants when listening to any of the gear
I've owned...does that mean my systems are crap?! I haven't crapped my
pants either...what does it say about a performance if you do that? Perhaps
great performances and great systems ought to come with a supply of

Woking "across" some of the interesting perspectives above, I would offer this:
Last night when listening to a variety of music, it didn't matter how this might compare to a "live music event". It was its own thing. I delighted in the clarity of the female vocal, for its inflection and the message that was communicated. This observation on reflection; the magic of the moment was on a different plane.
In the final analysis, whilst the real thing has always to be our reference (and stands apart in truth), the thing we have has its own, not inconsiderable joys.
Which is why we do this.
Drubin, I've been at the front tables many times at Mahanttan's Blue Note. Yes, that close you can hear many of these things, but then what you get is a different sort of presentation, not one that is any more or less demanding of an involuntary bodily reaction. I think you missed my point: what made the performance last night "great" was not garnered by an analysis of the sound, but of the wholeness of the event, a point where musicians, audience, and material were all in near perfect unison. I've been to countless live events; things like that don't happen too often.

I've found over the years that getting that level of musical reproduction at home is very hard. When we try to get "more detail" or "more midrange warmth" or whatever is your fancy, it sometimes winds up becoming a "part" of our systems. But, if we get what we want then I guess we're happy with what we get.
Marco, I'm not sure that what I'm trying to describe really is hyperdetail. I've heard ARC and Quicksilver tube gear sound wonderfully clear and open, and with the right recordings will give you that "open window" into the tiniest transients recorded on a disc or CD. But I agree it's not necessarily the same as hearing it through SS. I think your last part has it; we tend to look for things in our high end setups that will wow us, even if we strive for some level of realism and natural presentation. So maybe the subjectivist view has some truth to it: it sounds right if it recreates music to a degree that is ultimately satisfying to us.

I don't know that I necessarily agree with that; it bothers the engineer in me.