‘Joker: Folie à Deux’ Composer Invented an Instrument, Called “The String Prison,” for Sequel

Image from The Hollywood Reporter

• Gudnadóttir collaborated closely with director Todd Phillips, who gave her creative freedom to develop the film's sonic landscape, including the use of a unique 'trench cello' box-shaped string instrument from World War I.
• To capture the gritty, confined setting of Arkham State Hospital in the 'Joker' sequel, Gudnadóttir worked with a friend to design an electric fence-like 'string prison' instrument, which could get dangerously hot due to its amplified strings.