I'm not scheduled to attend this week's SFS concert, but I decided to respond to an invitation from the development department to attend an open rehearsal this evening. They sent me three separate and distinct e-mails, each strictly instructing me to print it out and use it for admission. The doorwarden barely looked at the first one before waving me in.
The main audience section was fairly full - enough to surprise some of those onstage with the size of the attendance. I was one of about 15 people who decided to go upstairs, which I did so I could see the entire orchestra, spread out in their street clothes.
Fortunately for my tastes, MTT decided to rehearse Beethoven's Ninth instead of the other piece on the program, which is by Alban Berg. If I understood correctly the assistant conductor, who gave a pre-show talk to the audience explaining where rehearsals had gotten to so far, this was the first time the chorus and soloists in the Ninth met to rehearse with the orchestra. MTT began with a stop-and-start run through the last few minutes of the Ode to Joy, then took the entire finale nonstop, then worked on some other sections.
After a break, he did a full run of the Adagio, a slow and contemplative version, before working extensively on individual passages, which left enough time for one quick run through the scherzo before the contracted quitting time.
The conductor's concerns were various and usually pretty subtle, but I could hear a crescendo in the chorus becoming more dramatic and vehement, and a long note in the Adagio getting just slightly extended. It was a good opportunity to hear part of the Ninth, in backwards order, in an informal setting, played splendidly well.