Learsfool, As the poster of one of the 'odd comments', lest I misunderstand, are you saying that you can distinguish the tonal qualities of each violin, and perhaps even be able to identify their maker by their particular tone, when the violins are playing en masse and you are sitting in the back of the hall? If so, you have a hearing ability that I don't possess. Just disregard the remainer of this post.
Or are you using the term in the context of being able to identify a particular type of instrument when it is playing with others, for example when all of the string instruments are playing the same music at the same volume (if this were even possible?) i.e. being able to distinguish between a violin, a viola, and a cello, playing the same note?
When using the term timbre I was using it in the context of how the violins (for example) sounded in comparison to each other, i.e. blended vs individually identifiable, not how they sounded when compared to winds, brass, percussion, nor how the various similar types sounded when compared to each other and what distinguishes their individual tones from each other. Apart from picking out instruments out of tune or players hitting sour notes I have doubts that fine distinguishing observations can be made from this distance between like (not just in the same family) instruments.
I would hope that most experienced folks can tell the difference between various instruments, even when some very similar ones play in the same register, but from the back row in the typical orchestral hall, at least the ones I have visited, I think even this would be very difficult for many folks unless there was a difference in pitch or volume to assist in the discrimination. Now if you can localize the source, its a walk in the park, but that has nothing much to do with timbre I think.
Perhaps we just use the word differently? When I have seen it used in this forum, for the most part, I have assumed the poster was simply referring to a speakers ability to replicate the sound of an instrument reasonably accurately, but only in certain aspects, which has as much to do with the speakers (and other stuff in the chain) level of resolution as anything else.
I think it must be so, since neither you, I think, nor I would ever listen to a speaker reproducing an instrument (let alone an entire orchestra) and think that we might be hearing the real thing and 'thus be able to identify with any sense of certainty subtle differences in 'timbre' between it and others of its kind.
Care to buy a 'Strad' based, not on its reputation nor after hearing it live, but only over a stereo system and relying on only what your hear then (not its reputation/cost/bling factors)? Would you be confident that its tone would be the tone that you would want as opposed to the tone of many other fine, but different, violins?
So when I listen to music over a stereo system I don't think in terms of its ability to resolve subtle timbre issues so much as to allow an open window to what the recording engineers put down. And only the lord knows what that might have been!
Now for my first cup of coffee...........