With his trombone alone, Bertl Mütter succeeds in bringing wonder-filled worlds to life. In mütterkinderlullabies, he hovers toward Gustav Mahler’s sonic universe: setting his own musicality apart from “Songs on the Death of Children”, he thus intersperses his improvisations with moments from Mahler, especially from the (carefree?) caprice of the wunderhornlieder. Musical density, the essence of Mahler made manifest, to the point where sounds no longer suffice.