Im Bau (In the Burrow) is the radio-opera version of Michel Roth's music-theatre piece after Franz Kafka's story Der Bau: fifteen composed sound spaces for mezzo-soprano, ensemble and live electronics. Somewhere between a live report and a stage production, the work mixes studio sound and recordings made in real rooms, and refuses to be tied down to a single genre. This is its first recording.

Roth is a Swiss composer and music researcher. He adapted Kafka's text himself and wrote the monodrama, about an hour long, on a commission from the ensemble æquatuor, the Lucerne Festival and the Theater Basel. The score is dated 2012/18. The singer is mezzo-soprano Anne-May Krüger. The ensemble includes Matthias Arter on oboe and lupophon, Ingrid Karlen on piano and melodica, Martina Brodbeck on cello and singing saw, Matthias Würsch on singing saw, and Ueli Würth on live electronics. Holger Stenschke was Tonmeister and handled post-production. The recordings were made in 2017 at the Hochschule für Musik FHNW and the Musik-Akademie Basel.

In 2017 the piece was produced as a music-theatrical obstacle course: the fifteen sound spaces interacted with fifty-three real spatial situations, partly in public performances, partly under studio conditions. Participants moved through the rooms, and the line towards reportage was deliberately explored. For the radio version Roth combined existing recordings from that production with new ones, so the result also tells the story of its own making. The fifteen rooms follow the stations of the story. After a prologue come the burrow itself, sleep (twice), the Burg-Platz or keep, the labyrinth, the moss cover, the open air, the outpost and a difficult return. Later rooms include Ein Zischen oder Pfeifen (a hissing or whistling), Verständigung (understanding), Der Bau im Bau (the burrow within the burrow) and an epilogue.

The project was also a piece of research. An interactive online documentation at imbauprojekt.ch links it to current questions about the radio opera and about radio-play versions of stage works. The recordings were made in the institutions of the Basel music university. The CD is therefore the final form of a work that existed first as a walk through rooms and then as a broadcast.

CD, Wergo WER 7384 2, released in 2019, first recording, total time 56'49".