Experimental musical instrument including intonarumori ("intoners" or "noise machines"), to create "noises" for performance. Unfortunately, none of his original intonarumori survived World War II. Replicas are being made though. Léon Theremin was a Russian inventor, most famous for his invention of the theremin around 1919–1920, one of the first electronic musical instruments. The Ondes Martenot is another early example of an electronic musical instrument. The luthéal is a type of prepared piano created by George Cloetens in the late 1890s and used by Maurice Ravel in his "Tzigane" for luthéal and violin. The instrument can produce sounds like a guitar or a harmonica,
Musical instrument which produce sound by electronic means. Within each category are many subgroups. The system has been criticised and revised over the years, but remains widely used by ethnomusicologists and organologists. Andre Schaeffner, a curator at the Musée de l'Homme, disagreed with the Hornbostel-Sachs system and developed his own system in 1932. Schaeffner believed that the pure physics of a musical instrument, rather than its specific construction or playing method, should always determine its classification. (Hornbostel-Sachs, for example, divide aerophones on the basis of sound production, but membranophones on the basis of the shape of the instrument). His system divided instruments