You know, I really liked the "steampunk opera" Miranda. It's an opera which was being performed at HERE. But it was very flawed. The biggest flaw was in the sound. All of the vocals were mixed just under where they needed to be. And that's the fault of the music being too loud, not the voices being loud enough. The mix was loud enough that the room itself could just barely handle it without becoming just a harsh icepick aimed at the audience's head. Or about 85 - 90 dB SPL.
But that meant that, even without worrying about gain-before-feedback, there was no way to make the voices louder than that because they'd just become strident and irksome.
Although the show was produced by HERE, a Kickstarter campaign was used to pay the musicians. To me that sounds like a pretty smart way to use Kickstarter.
(Note this video is not from the recent performances -- the performance I saw ironically didn't sound this good although this may have been a special mix from the board rather than a mic sitting on the camera.)
Continuing the problems with the sound, the romantic lead was singing way below his range. And the only way to deal with that is to turn up the volume (see problem number one, above). And although she's a pretty good singer, Kamala Sankaram doesn't do that necessary thing where you sing quieter as you go higher. Instead she uses her support for volume rather than, you know, support.