The halldorophone (Icelandic: dórófónn) is a cello-like electronic instrument created by artist and designer Halldór Úlfarsson. The halldorophone is designed specifically to feedback the strings  and the instrument gained some recognition in early 2020 when composer Hildur Guðnadóttir won the Academy Award for her original soundtrack to the movie Joker, some of which was composed with a halldorophone.
- "This strange instrument from Joker soundtrack was invented in Finland". Aalto University. Retrieved 2020-10-26.
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