“We’re sitting here wrapped in French walnut,” says Sylvia Weber. The head of the art and culture department of the Würth Group explains this effect as follows: There are only four and a half walnut trees to clad the walls of the concert hall with around 600 seats – about as many as on the ground floor of the large hall of the Mozarteum Foundation in Salzburg been used. “So thin!” Assures Sylvia Weber. In this paneled cube made of even and varied, vertical brown tones, you feel like you are in a …