Key (instrument) Key (instrument) A key is a specific part of a musical instrument. The purpose and function of the part in question depends on the instrument. On instruments equipped with tuning machines, violins and guitars, for example, a key is part of a tuning machine. It is a worm gear with a key shaped end used to turn a cog, which, in turn, is attached to a post which winds the string. The key is used to make pitch adjustments to a string. With other instruments, zithers and drums, for example, a key is essentially a small wrench used to turn
Geophone (musical instrument) performance in New York City). Messiaen's wife, Yvonne Loriod, commented that when she and the composer first collected the new instrument from the maker in her car it made a "splendid crescendo" whenever they went round a corner. Messiaen also included the instrument in his only opera, "Saint François d'Assise", which was first performed in Paris 1983. Other works that use the geophone include "Asyla" by Thomas Adès, "…towards a Pure Land" by Jonathan Harvey, and the operas "The Sacrifice" by James MacMillan and "Dark Sisters" by Nico Muhly. Geophone (musical instrument) The geophone is a percussion instrument, invented by