Hearing a small baroque ensemble in a good hall really puts into perspective how far reproduced music still has to go. What gets me every time is the tremendous dynamic range skilled acoustic musicians can bring, far more shadings than a typical rock band's two settings of 'loud' and 'louder still'. It's not just players in the 'classical' world that have this skill, great bluegrass players 'swell' the volume very organically too.
Another suggestion for the those wishing to treat their ears would be to go hear a quality vocal ensemble. Living in the Bay Area for years, I heard Chanticleer many times, astounding how rich and well balanced their voices are. They tour the world, here's a link to their schedule:
Chanticleer: An Orchestra of Voices