for the film, lang commissioned a composer for the first time. hans erdmann created the opening theme and the music played during professor baum's madness. the soundtrack in the film is deceptive. as in lang's "m", the film's music and sound are a subtle mix of actual silence with accompanying music and more or less realistic sound effects. lang worked with his german editor conrad von molo directly on the post-production process. lang was known for making very long films and to suit foreign fashions, editor lothar wolff was contracted to shorten the french-language version. this version deletes parts from the romantic sub-plot between lilli and kent.