The few times I seen/heard The Unanswered Question performed live, the strings were behind the stage curtain, the trumpet was out in the audience in a balcony, and the woodwinds were on stage....
My first hearing of it was live, in my early teens. It made such a strong (negative) impression on me that it poisoned my opinion of Ives, and of 20th century American music in general, for decades afterward. Listening to it again now it doesn't sound nearly as bad, or as shocking, as I thought it was back then.
The performance I saw had only the trumpet offstage. Probably just a matter of space, nowhere to hide the whole string section.
My best friend at the time was a violist, now deceased, who loved Webern and Stockhausen, and insisted that I give each of them a try. I did, but wasn't particularly receptive. I tried to seduce him into loving Wagner and Sibelius, with similarly unsuccessful results. We met in the middle and both embraced Shostakovich.
Compared to this next one, by Ives's contemporary Anton Webern, The Unanswered Question is like a lullaby.
You may be surprised that I would have said the opposite.
The Webern is more-or-less honest up front about what it's going to be. I could actually imagine falling asleep to it, sort of like listening to a wind chime outside my window. The Ives...sneaks in under false colors, grabs you by the earlobe, and twists. It leaves me wide awake, unsettled, and ready to kick the next animal that crosses my path.
I suppose that means it's effective, in its way. I do have a reaction to it, vs. the Webern.
Sorry for contributing to derailing the minimalism thread - I suppose I should have followed Tom's example and moved this topic elsewhere.