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
A (musical note) A (musical note) La or A is the sixth note of the fixed-do solfège. Its enharmonic equivalents are B ("Heses") which is a diatonic semitone above A and G (Gisis) which is a diatonic semitone below A. "A" is generally used as a standard for tuning. When the orchestra tunes, the oboe plays an "A" and the rest of the instruments tune to match that pitch. Every string instrument in the orchestra has an A string, from which each player can tune the rest of their instrument. "A" is also used in combination with a number (e.g. A-440) to label