Roald Dahl's 1949 short story "The Sound Machine" is about Klausner, an obsessive man who invents a machine that allows him to hear high-pitched sounds otherwise inaudible to the human ear. While testing his sound machine, Klausner discovers that roses shriek when their stems are cut. In another test, Klausner swings an axe at a tree and is horrified by the low growl of pain the tree emits. Klausner attempts to reproduce the sound for the doctor who periodically checks in on him, but the test proves inconclusive when a large branch falls from the tree and smashes the sound machine. Holding the axe menacingly, the man orders the doctor to apply iodine to where the axe wounded the tree. The doctor obliges and calms Klausner down before he rushes Klausner back to the man's house. Throughout the story, it is ambiguous whether Klausner's findings are scientifically sound or the consequence of mental instability.
Written from the perspective of a third-person, limited omniscient narrator, the story presents no conclusive judgment as to whether Klausner truly hears the rose stems and tree making sounds of pain. Dahl replicates the narrative ambiguity in the doctor's attempts to assess Klausner throughout the story: it is unclear whether the doctor is witnessing the ravings a madman or the obsessiveness of a genius. Ultimately, Klausner's emotional volatility and the doctor's decision to rush him inside suggest the doctor believes Klausner is having a psychotic episode.
First published in The New Yorker magazine in September 1949, "The Sound Machine" later appeared in three collections of Dahl's stories: Tales, Someone Like You, and Grammatatizator.