The discussion of the appropriate metaphor has actually been very helpful.
First, where we seem to agree. Different things sound different. A violin sounds different from a bass. A trumpet will not sound like a sax. No one will ever confuse the Vienna Boys Choir with the muppets Christmas album (which my wife nonetheless insists on subjecting me to every year. Something about childhood. Jeesh.) Doesn't matter what you reproduce these sounds on, you will hear the difference. I can hear the difference on the mono 1mm speaker on the iPad. Anything will be up to the task.
Second, things that are supposed to be the same can also sound different. One piano -- or any other type of instrument -- will not sound like every other piano. Ah, you say, but there are different types of pianos, of course those sound different. Yes. But it starts to get more interesting as we narrow our comparison set. Back to violins: folks who are trained to appreciate the differences can perceive the distinctions between, say, a Stradt and something else. Some will perceive the distinction between one Stradt and another. Yes they are more similar than different, thus identifiable as a class, but also individually distinguishable. They sound different. Could I hear that difference? Not a chance. My brain hears "violin" and stops processing -- it's never been trained to parse finer. Example, like why US troops used "lalapalooza" as a password in Asia during WWII. Certain languages do not contain sounds to distinguish between "L" and "R." If you grow up speaking said language, your brain never develops the processing bandwidth to make that distinction, and while your ears will hear the difference, your brain will simply not register it, and you won't perceive it. Same with violins or, for that matter, everything else. But a useful concept for the discussion: the difference between making (or reproducing or "hearing") distinct sounds and the ability (training, expertise, cultural, etc) to actually perceive the distinction.
This, of course, is where one may be prone to veer off into the mental masturbatory quagmire of debating objective vs subjective based reality. Is the world comprised of objectively verifiable truths, independent of any perceptual framework, or is all reality ultimately dependent on, and mutable as a product of, the particular lens through which it is being perceived? We won't be solving that one today. Just let's stipulate that folks have been debating that one for as long as there have been folks, you'll likely instinctively feel that one makes more sense to you than the other, and just make peace with the fact that about half of the people out there will think you're wrong. Moving on.
To return to the regularly scheduled programming, all of this discussion on one level misses the mark in that we're talking about original source material (a violin) rather than the task of reproducing that original source by recording it and then playing it back. One might observe, but the issue isn't whether the two violins sound different, but whether the recording and playback exercise can preserve and reproduce that distinction. I would argue, this is only partially correct. First, yes, can be reproduced. Second, however, this line of inquiry potentially confuses the issue. The ability of two sets of speakers to reproduce the ability to distinguish between two violins in no way means that either speaker sounds like the other one, or that either is closer to "truth." Guess the only way to do that would be to put the original head-to-head with the recording and see how that goes. In short, an "apples to apples" comparison (violin vs violin) ain't our project, we really need an "apples to oranges" comparison (violin vs speaker) to address our question. Yes and no.
The violin vs violin analogy becomes interesting if we, for example, contemplate comparing two identical pairs of speakers, coming out of the same plant on the same day. Will they sound identical? Only practical way I can imagine to do such a comparison would be in the testing room at the plant, on identical equipment, in the same controlled environment. Would the two sets of speakers be indistinguishable? No idea. Bet the manufacturer hopes so. Bet that's, in fact, exactly what they test for. Do all the speakers "pass"? Doubt it. If drivers are carefully "matched" pairs, must be a reason -- and that reason necessarily implicates that "unmatched" drivers, say, as between two otherwise identical pairs of speakers, sound appreciably different, at least to the ears of the designer. Otherwise, why bother? Say we then ship the two pairs of speakers to different customers, who install them in different rooms, on very different systems. Will they sound the same then? Almost certainly not. And say they continue to play for ten years in those different systems -- if we then ship them back to the manufacturer for a turn in the identical test system, in the same room, are they going to sound the same (or as close to the same) as they did when fresh off of the line? Again, no idea, but a lot more reason to question the proposition....no?
If we assume all of the preceding (your call), the question becomes whether one could reasonably expect two entirely different speaker systems (different manufacturers, electronics, enclosures, drivers, materials, sizes, designs, etc) to sound indistinguishable -- not because anyone ever intended them to be identical -- but almost by accident because each was independently designed to be able to sound like, for example, the same recording of the same violin. That's really the question, right? My response is, if we can't reliable make two violins that sound identical, if we can't even reliably make two identical speakers sound identical -- even when we're trying really hard -- how could we expect two entirely different speakers to sound identical by accident, just because they were aiming at the same target? Might it be possible? Sure, and infinite monkeys are bound to pound out Shakespeare. But I don't see it happening. (BTW, I think this is fun, not that I am entirely sure I like what that says about me....)
