Here are some things you might not have thought of that go into the rehearsal period:
Coordinating the lights with the flow of the opera. Coordinating the video with the flow of the opera. Who takes the first bow, and who goes next? Who goes and gets the video guy for his bow? Who moves the microphone that is used in the talking skit? Where does it go?
The rehearsal we just finished solved all these and more. We barely played, the singers barely sang. It was a rehearsal whose sole concern was transition and the smooth completion of same. Herky-jerky, at times tedious, and crucial to the success of a show. Your typical classical music concert is about as unconcerned with choreography on stage as can be (“I’ll go out first, since I have the farthest to walk” is about the limit of planning), whereas an opera, being a play, must be meticulously planned. At a house such as the Met in New York, where hundreds of people are employed backstage, the working out of these details is a gigantic task, finely coordinated. Here, with maybe 15 people, at least we can cover a 50-minute opera in about 90 minutes of cue rehearsal.
Now: a run-through, start to finish.