Twenty Studies R. Kreutzer arranged by Jacques DelĆ©cluse (born 1933) is a set of twenty studies written for Xylophone . Inspired by a set of exercises for Strings written by Kreutzer Twenty Studies after R. Kreutzer covers passages that would often be seen in modern orchestral music. Rudolphe Kreutzer was a French violinist conductor and composer and the author Jacques DelĆ©cluse is a soloist at the Paris Orchestra and a professor at the Paris Conservatoire. He has conceived a keyboard-percussion instrument that holds his name and is also the author of a series of seven books“ƀ la maniĆØre de” for Drums and Piano.