To mark the start of KlangBasel 20/21 and the conclusion of the opening ceremonies of
the La Cetra Barockorchester Basel and the Sinfonieorchester Basel a special experiment: the two orchestras are taking each other to the Beethoven anniversary four of the nine symphonies and change their conductors. Andrea Marcon, musical conductor of the La Cetra Baroque Orchestra, conducts his own orchestra through the 2nd symphony D major op. 36 and later leads the Basel Symphony Orchestra through Symphony No. 7 A major op. 92; his colleague Ivor Bolton, chief conductor of the symphony orchestra, takes
his orchestra of the Symphony No. 5 in C minor op. 67 and presents with La Cetra the Symphony No. 8 in F major op. 93: The audience can follow at close quarters how the sound of the two orchestras in the symphonies composed in a quasi "double pack" changed.

Between the symphonies, 's Echo vo dr Feldbergstrooss sings traditional nature yodel and compositions inspired by Beethoven. Dina Jost and Thomas-Maria Reck are two Nature voices. They yodel on the roof, under the bridge, in street canyons, in the park, on the tram and this time on the gallery in the City Casino.