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."
Let me make my point another way, with an analogy. Let's say instead of listening to music, we just liked LOOKING at birds. Well, as it so happens, for one reason or another, we can't always be outside to look at the birds or, some birds don't live around our homes so, we're relegated to looking at pictures of birds when it's convenient for us. However, we do have access to pictures painted by artists who's ability to reproduce birds is so lifelike that we could swear the birds were standing here with us. Now, let's say another artist, maybe Matisse or Picasso paints a bird. Clearly, their interpretation of a bird is NOT reality. However, there are probably tons of people that will get excited over their interpretations and would love to look at their interpretations of birds. But, we can objectively say that Matisse and Picasso are NOT painting pictures of birds; those that we like to see as we would have seen them, had we been there in person. Clearly, in this analogy, the birds are music, the realist artist is the transparent playback system and the impressionist and cubist artist is a "non-transparent" system. I love music. I listen to music in my home because the artists I like are either dead, or not performing in my home when I want to hear them. So, I HAVE to listen to a recording of them. And so, I would like it to sound as closely as possible to the way it would have had I been there at the recording/performance. Thus: Transparent playback system, and the pressure's on the performance and the recording engineer.
Your analogy is an excellent one, though as a painter I might consider the final product to be made less transparent by a glaze, a glass cover, and a complimentary frame. These ancillary effects are often made present by certain components, cables, tubes, tweaks, etc. And they may be exactly what my audiophile buddy wants, but instead might leave me wanting them gone. Because in the end, I don't believe we are looking for a connection with the music, but rather one with ourselves.

In regards to that bird, no two people observing it live would see the same thing. By the same token, you and I could listen to a live concert and you might come away saying that the singer really moved you because she is so close to the words, and I might interpret her as forcing it. You might come away with the impression that the sound was transparent, and I could find it muted. Whether at a live performance, or a recorded one translated via an audio system, everything is left to interpretation by each of us. And our own personal, individual conclusion IS our reality, whether fleeting or fixed. Sometimes it may feel more solid if we pair up with others of the same opinion, but it doesn't transform group opinion into empirical reality. It only makes you all friends.

So, to answer your original question posted here, I would have to say that unless Diana Krall pops out of my Klipsch speakers--and you know I'm praying that tonight she does--I am relegated to enjoying her recorded music through the system that I (and in this case, my wife AND I) determine to meet our standards for musical reproduction. And fortunately, our system does that really well...in our OPINION.

Next week, I'll be 40 years old. And in my brief time here, I have thus far earned only one unshakable truth. That is, Steve Guttenberg is a crappy actor. Now, back to the music!
Fabulous topic with existentialist leanings, I love it!
For mine, we walk a tightrope in "Audiophilia". There is this side that says "accuracy" is what we need, that what comes out of our speakers is as close a reproduction of what is going on upstream. What IS this accuracy thing anyhow?
If I want a "kind of accuracy" I can get vanishing-low thd from a seventies integrated SS amp with bucketloads of feedback. But does it "make music"? Not for me.
As for the "musical" thing, what is that? What makes a musical "connection" to me is another person's poison.
Recreate a "live sound"? This is always our reference point, it must be. Someone alluded earlier to the notion that live music "kicks your butt" or to that effect. Doesn't it though? There is nothing "polite" about a trumpet played with passion. So for me the "smooth, laid-back sound" doesn't cut it, it doesn't kick my butt. For others, that kind of sound just might "welcome them in to the performance". So be it.
So for me, I want a speaker that makes it all "HERE!", as much as I can.
Never having been blessed with a system that simply Does It All, I make my compromises how I think they work best for my way of appreciating the performance. In a way, since we can't get a "perfect" speaker/system that it voices, you kinda choose your coloration, and the more we do this audiophile thing, the better an idea we have of what that is, referring always back to live music.
PBB, I didn't forget you. One of the basics of sound reproduction and perception is that the ear's sensitivity to frequencies changes with the sound pressure level. Ever notice that there's a just-right playback volume? For example, below that level there's not enough bass, above it there's too much. That's your ear at work. In the context of this thread this means that the elusive wild goose of transparency can only occur at one volume setting for each recording. At all others the perfect system will sound out of balance, and so by definition, non-transparent.
Absolutely, Rockvirgo!
For this reason, in a practical sense, I'd rate a remote volume control more important than a "technically superior" one in most circumstances.
There seems always to be the "right volume", although the best systems seem somehow to work in a wider range of "close enough".