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) Geophone (musical instrument) The geophone is a percussion instrument, invented by the French composer Olivier Messiaen for use in his large composition for piano and orchestra entitled "Des canyons aux étoiles…" ("From the canyons to the stars…"). It consists of a drum filled with thousands of small lead pellets, and is played by swirling it around slowly so that the noise of the pellets resembles the sound of dry shifting earth. Messiaen commissioned a Parisian instrument maker to construct one to his design, and he carried this instrument worldwide to early performances of the piece (which was given its first