wht is the difference between good and bad sound ?

The difference between good and bad sound is mainly in the skill or luck of the person putting the system together. Neither the Toyota nor the Merc are bad cars, but you can drive a bad Toyota or a bad Merc. Of course there is gear that will always give bad sound, but it is rare. For me bad sound becomes a dense wall of sound where I cannot hear into it in arder to distinguish the sounds of different instruments and how they are being played, where I cannot hear the different textures each instrument possesses. This can happen with expensive gear more frequently that inexpensive gear can sound good, but both can sound good and both can sound bad. As I say the skilled or lucky audiophile can make good sound with a small budget, but this is not to say that he can make as good a sound with a bigger budget. The dense wall of sound effect occurs IMO when the brain cannot decode what it hears, ie the distortions are too unnatural or too numerous for the brain to make sense of them. Good sound can be distorted too, but if the brain can make sense of what it hears then it matters a lot less. Real music in real rooms is distorted too, but in a way where our brains have learned to cope.

Mrtennis, I wasn't trying to enter into the existentialist debate, just describe how good and bad sound occur for me - no more and no less. Good and bad are generalised terms to describe what must be a continuum and may have several dimensions. You can describe any observation as 'in the eye of the beholder'. Is this sheet of paper white, or is the only fact that I perceive the paper to be white. Me perceiving it to be white does not preclude another person perceiving it to be grey. So where does this get us? Not far unless you just like such debates. But the counter-factual, which could be that noone should ever describe here something as sounding good/bad, or better/worse than anything else seems to me to lead to reducing the sum of our enlightenment. Just because we cannot prove many useful facts about sound does not mean we cannot discuss the observations that have occurred to us. Take everything with a grain of salt, but don't dismiss all reported observations as meaningless.