Wow, lots of posts since I checked in, been super busy so no chance to reply in time.
On recordings, I'd just say that unless you're familiar with recording music and playing it back on your own system you're just guessing on what sounds right. Even then, as @microstrip correctly pointed out, mic choice and setup can make a really large difference, but you should still get the overall "vibe" and space of the venue.
So I'd just put out there that these live vs system comparisons are confounded by the fact the listener has no point of reference whatsoever.
Well, we must rely on memory because we can not simultaneously listen to both an original live event and a recording of that event. As far as references go, how would we even know what a piano sounds like if we have not heard a live piano? And for recordings, can we not listen to that same recording in a number of different systems, familiar or not, and get some sense of its quality? People demonstrate systems and judge their quality by playing reference recordings.
IME, there are other points of reference that are actually objective and can lead one to the traditional definition of "high fidelity" TO THE RECORDING. And if that fidelity is realized it will also make live recordings sound more real. In other words, you can absolutely disregard any live music references, as they are going to be very subjective and honestly, not based in reality. People complain that it's difficult to hear differences in A/B testing separated by mere minutes, yet we're supposed to buy into the idea that someone can judge what sound realistic and natural based on their individual subjective experience of live sound separated by hours, days or weeks? Even when the person was not present during the recording, and has no idea what the recording setup looks like or what the intent of the folks doing the recording is?! Really? Sorry but this seems absurd.
I fail to see how a live music reference is not based in reality. I hold that listening to live music is reality. Yes, it is often difficult to hear differences in A/B testing. Sometimes that is because the differences are extremely subtle. It is much easier to tell the difference between live and reproduced music, even if separated by time. I recording of a piano does not sound exactly like a real piano, but we have a sense of what a piano should sound like if we have heard a few in a variety of settings. If we are A/B testing two speaker cables or power boxes, how could we possibly know which sounds more realistic (if that is one's goal) if we did not have our memories of what real music sounds like. Of course real music is a reference, though it seems not for everyone.
A better way to judge system performance is how unique it can make each recording sound, or put another way, how little it adds of it's own character overall. We can easily judge resolution by how well it presents spatial attributes and how realistic and distinct the timbre of complex instruments like strings and vocals are. Vocals are especially hardwired into our brain because we hear it live everyday and it's not difficult to tell how well a system recreates vocals. How different does a violin sound vs a viola? All these things can be measured in comparison, while not as satisfying as a measurement, it's still possible to objectively determine how neutral a system is to the recording. And by objectively improving our system's performance, it will allow live recordings to sound more live, and for the system to more accurately portray the intent of the recording.
Again, how can we judge any of that without referring back to our memory of the timbre of complex instruments like strings and vocals? How do we know that a violin sounds different from a viola unless we have heard them live and can remember their differences?
How do we know what the recording should sound like, or how neutral a system is to the recording? What do we use as a basis for judgement if not the sound of actual instruments? We can listen to sounds and have a preference based on their effect on us.
I agree with you that a good system will clearly distinguish one recording from another and that it will allow a live recording to sound more live. But again, we can't know what live means unless we have heard live. It is our reference and we rely on our memory. Are you suggesting we rely on something else, like our imaginations?
What we need overall is a balance between preference and objective performance. Personal preferences are totally valid but can be informed by making sure the system works well on an objective level. An example: Many people ask me for a warm cable, they tell me their personal preferences are for a warm tone. I send some cables to demo, one of which will absolutely not be warm, it will be as neutral and resolving as possible. A vast majority of the time, maybe 80-90%, I'll hear back that the person prefers the neutral cable. We need some amount of warmth to smooth out noise and artifacts, maybe hide flaws in a poor recording, but the better the system the less warmth required. When people hear a neutral cable that improves spatial performance and timbre, and understand the difference between the two, almost everyone without exception prefers the sound of a neutral and highly resolving cable. Their desire for improvement is real but they don't necessarily understand what will satisfy that desire until they experience it.
I agree that neutral is good. A truly revealing system will present much of the rich tone of instruments if captured on a good recording. Neutrality, transparency, lack of coloration are some of the important qualities of a good system.
So sounding "natural", or like your own subjective experience of live music sounds good in theory, who wouldn't want that? But it's not achievable using the metrics espoused in this now 336 page thread because 1. The recordings don't exist or are very rare, and 2. You have no point of reference to judge what you're listening to unless you were there yourself.
1. I agree that great recordings are rare, but there certainly are many, many wonderful sounding recordings that one can collect and that provide much enjoyment. The recording is one aspect, the system is the other for natural sound. Certain recordings are acknowledged as references specifically because of how they can sound on systems. Reviewers describe the very qualities of various recordings that make them special and worthy of attention. Whole labels have certain reputations, as do engineers. There is some standard by which they are judged. And that standard is often the sound of actual music.
2. Of course we have a reference to judge what we are listening to. We have our experience based on living in the real world and listening to real voices and instruments in real rooms. Together, these form a basis by which we can judge performance. I heard a live performance of a string trio the other night. I have recordings of string trios. I can certainly judge how convincing they sound, in my system and in other systems. And I am sure that I am not alone. We do not listen to music on our systems in isolation, devoid of past experiences.
As I had suggested, a discussion about "separation of instruments" might well be controversial. These last few pages show that. I hear more separation of instruments from some playback systems, often much more, than I hear this quality from live music. Many of the recent posts do not really address that point but rather attempt to explain why recordings or systems might enhance this effect. Some of us do indeed compare live music to reproduced music as I did here with my recent experience listening to a live string trio in a nice hall. It seems others do not value such comparisons and seem to prefer enjoying each experience for its own merits and qualities. That is fine too. They are different experiences. Some of us attempt to make them more similar than different.