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,
Signal instrument Signal instrument A signal instrument is a musical instrument which is not only used for music as such, but also fit to give sound signals as a form of auditive communication, usually in the open air. Signal instruments are often contrasted with melodic and diatonic or chromatic instruments ("a musical (rather than signal) instrument" is not uncommon phrasing). To make the message audible at a distance, percussion and brass instruments, which are generally loud, are chiefly used for this purpose. There are contemporary instruments which evolved from signal instruments, such as the natural horn evolving to the trumpet. Before the