The Bregenz Festival began on a very small scale in 1946, directly after the Second World War, while this part of Austria was still under French military rule. The stage that first summer consisted of two small barges moored in Bregenz harbor.
That first year, the festival already included two concerts by the Vienna Symphony Orchestra (Wiener Symphoniker), added to the program at short notice. The musicians were in the area because they were scheduled to give concerts in Switzerland, but the French military authorities stopped their bus and wouldn’t let them cross the border. The people of Bregenz housed and fed the stranded musicians in return for two concerts — and the orchestra has been coming back to Bregenz every summer since then, to give concerts and to play in the opera performances.

Tower next to the stage, with loudspeakers and monitors
For many years at the Bregenz Festival, the musicians had to sit and play in a concrete trough directly beneath the stage. But in 2005, for the first time, they were placed in the orchestra pit of the large indoor hall underneath the grandstand, and the music was transmitted to the outdoor stage through the new Bregenz Open Acoustics sound system.
This is a much better arrangement for the musicians and also better for the acoustics, because there is more scope for the proper placing of microphones. Another nice side effect is that in case of rain the orchestra doesn’t have to move indoors, because it’s already there.
Moving the orchestra indoors in the rain used to be a major hassle, since there is only one narrow pier leading to the shore. Getting all the musicians across the pier, while keeping their instruments dry, was a vexing challenge in those years, the only consolation being that most years it didn’t rain very often, typically only once or twice during the five-week opera season.

Control room with camera
This is the video camera that is trained on the full stage during the whole performance, so the orchestra conductor can see what is going on out there. It is located in one of the control rooms at the top of the grandstand.
A second monitor lets the conductor see the indoor chorus, which is behind his back in the large hall. The indoor chorus is the one the audience hears over the sound system. The outdoor chorus, which we see on the stage, also consists of trained singers who are really singing Verdi’s (or Puccini’s or whoever’s) music, but their voices aren’t being amplified.
At the same time, live pictures of the conductor or the musicians (all wearing blue shirts or blouses) are shown throughout the performance on two large monitors to the left and right of the grandstand outdoors. There is always a knowledgeable person at the controls, to ensure that the right musicians are on the screens during their big solo passages.

The stage from the top of the grandstand, 2005
At some point in Bregenz I learned that The Vienna Symphony and the Vienna Philharmonic are two different orchestras. The Philharmonic is older, having been founded in the 1840s by the composer Otto Nicolai, whereas the Vienna Symphony Orchestra wasn’t founded until 1900.
Besides playing in Bregenz every summer, the Vienna Symphony Orchestra also plays (since 2006) in opera performances at the Theater an der Wien in Vienna.

The Bregenz festival grounds
My photos in this post are from 2005. I revised the text in 2022.
See more posts on Bregenz, Austria.
Very interesting Nemorino
I think it would be better to hear the music directly without electronic transmission. But I’m probably in the minority. At college, we had a theater built which had perfect acoustics – anyone in the audience could hear a pin drop on stage. But they forgot to account for an orchestra pit. It was added later. And the acoustics for that were bad. The only one in he pit who could hear the singers (and see them) was the conductor, and the singers couldn’t hear the orchestra well either.
Yes, I also prefer to hear the music directly, without electronic amplification. That’s the way it is in opera houses, and even in the Arena in Verona, which seats twice as many people as Bregenz. But in most outdoor venues that isn’t possible, so they try to compensate electronically as best they can.