what is good sound ?

It is most certainly all subjective. The idea of "High-Fidelity", or being 'true' to some objective concept of what the music is "supposed" to sound like is both absurd and contrary to what the enjoyment of music, or any art form, is all about. More to the point, it just doesn't matter. It reminds me so much of a dog chasing its own tail in circles. The ultimate goal for me is when the gear gets 'out of the way' and I no longer pay any attention to it at all, and am totally absorbed in the presence of music. My idea of what that sounds like is likely going to be somewhat, or completely different to what someone elses idea of what that sounds like might be. The same way you might choose a different tennis racquet, different auto, different flavor of ice cream than someone else...whose to say one is "better" than the other in objective terms. Each may suit a different individual and become the 'best' in their experience...whether or not some collective somehow decrees one or the other widget to actually be the very "best" widget, really should not matter one wit to anyone. Find your own "best" - you are human after all and cabable of your very own set of distinctions, and certainly prone towards making meaning out of everything you experience.

Marco

marco, i9 agree with you in principle. for me, the closer i get to the sound of an instrument in a live setting, the happier i am.

But, what if the instrument is an electric guitar going through Marshall stacks and a soundboard of questionable quality?

for me, the closer i get to the sound of an instrument in a live setting, the happier i am.

Then spend more time listening to live music.

You're subject is the reproduction of that music by an artificial means. First off, what music sounds like in a live setting may be different to you than it is to me. It will certainly be different depending upon the setting, where you listen from, live mixing, the crowd, the room, your mood, blah, blah, blah. Sometimes live music can sound simply horrible, as we all know, and we wonder why we spent the coin when we could be more moved by the same music on our own system at home. It happens. It all comes down to subjective opinion...what makes you "happy" may not be what makes me "happy". That said, yes, I think I agree with you on some level that what one of the things that engages me most about my system is the illusion of a 'realistic' presence. I don't know that brings us much closer to some objective definition of "good sound" though but I suppose it's something. Again, it becomes subjective...those qualities in a system that make music sound "live" to you may be quite different to those that I am engaged by.

Marco