The Alte Oper in Frankfurt is a hall which has been completely gutted inside and modernized. You wouldn't guess from the exterior which is in the 19th century heavy, Germanic style. Inside it is cavernous with a sort of raspberry colored hue on the seats, wall and floor. Banks of lights and speakers betray its mult-purpose use. The acoustics are also cavernous and comfortable with a lot of bass resonance.
Tetzlaff gives a very personal, stylish performance of the Beethoven Concerto, emphasizing its intimate side over the monumental. He also avoids Joachim's cadenza, using his own patterned after the one Beethoven wrote for the piano arrangement of this piece.
Here is his performance with the Tonhalle Orchester on YouTube. About 18 minutes in you can hear this cadenza.
There is a timpani accompaniment to this that's fun. It's not a very cohesive cadenza musically -- much of it seems to have little to do with the first movement themes. But a nice change from the usual. Gidon Kremer also wrote a cadenza that challenges the tradition of Joachim.
The performance went well considering we just rehearsed once for an hour and then played the piece.
The next day I went for a rainy, cold run on the banks of the Main River, then sought out a music store near the hotel -- Musikalien Petroll -- which has a basement full of used music. I bought parts and score to a Vivaldi Bassoon Concerto for 3 Euros.
That night we played the Beethoven Mass again.