I just found an article from the Philadelphia Inquirer that considers the increasing trend of explaining the music before a classical music concert to be hurtful rather than helpful. Here is an excerpt:
"Yet the question remained as to how useful information is in art. If there's a formula here, it's that knowledge equals understanding equals appreciation. But what's really needed is an intuitive response. My strongest emotional experiences of the two concerts were where understanding didn't come into play. The copious Rothko Chapel explanations felt like layers of scaffolding that were meant to buttress the experience but might have obscured what's there - and taken away a sense of discovery. All you really need to know is that Feldman makes expressive use of silence and composed with sophisticated structural concepts."
I had been convinced more and more lately that more explanations were the way to go, but now I'm not quite sure (although I haven't quite changed my mind completely). Of course, I'm sure there isn't any particular rule that would work in every given situation, and that the performers or music directors would have to just use their own judgement, based on who they expect their audience to be. In class we've discussed cases in which prior explanations seemed to get better responses from the audience... I wish I could wrap up this post with some sort of stance one way or another, but I really don't have one right now. I'd be curious to hear what everyone else thinks about this.