Editing Key (music) (section)

==Instruments in a key==
Certain [[musical instrument]]s play in a certain key, or have their music written in a certain key. Instruments that do not play in the key of C are known as [[transposing instrument]]s.<ref>[[Kent Kennan|Kent Wheeler Kennan]], ''The Technique of Orchestration'', 2nd edition (Englewood Cliffs, New Jersey: Prentice-Hall, 1970), 1952; {{ISBN|0-13-900316-9}}.</ref> The most common kind of [[clarinet]], for example, is said to play in the key of B{{music|flat}}. This means that a scale written in C major in [[sheet music]] actually sounds as a B{{music|flat}} major scale when played on the B-flat clarinet—that is, notes sound a [[whole tone]] lower than written. Likewise, the [[French horn|horn]], normally in the key of F, sounds notes a [[perfect fifth]] lower than written.

Similarly, some instruments are "built" in a certain key. For example, a [[brass instrument]] built in B{{music|flat}} plays a [[Fundamental frequency|fundamental]] note of B{{music|flat}}, and can play notes in the [[harmonic series (music)|harmonic series]] starting on B{{music|flat}} without using valves, fingerholes, or slides to alter the length of the vibrating column of air. An instrument built in a certain key often, but not always, uses music written in the same key (see [[trombone]] for an exception). However, some instruments, such as the diatonic [[harmonica]] and the [[harp]], are in fact designed to play in only one key at a time: [[Accidental (music)|accidentals]] are difficult or impossible to play.

The highland bagpipes are built in B{{music|flat}} major, though the music is written in D major with implied accidentals.

In Western musical composition, the key of a piece has important ramifications for its composition:

*As noted earlier, certain instruments are designed for a certain key, as playing in that key can be physically easier or harder. Thus the choice of key can be an important one when composing for an orchestra, as one must take these elements into consideration.
*In the life of the professional clarinetist, for example, it is common to carry two instruments tuned a semitone apart (B{{music|flat}} and A) to cope with the needs of composers: [[Mozart]]'s well-known [[clarinet concerto]] is in A major. To play it on a B{{music|flat}} instrument is difficult, and to rewrite all the orchestral parts to B{{music|flat}} major would be an enormous effort. Even so, it is not unheard of for a piece published in B{{music|flat}} to include notes a semitone (or more) below the range of the common B{{music|flat}} clarinet. The piece must then be played on a more exotic instrument, or transposed by hand (or at sight) for the slightly larger A clarinet. There are clarinets with an extended range, with a longer bore and additional keys.
*Besides this though, the [[timbre]] of almost any instrument is not exactly the same for all notes played on that instrument. For this reason a piece that might be in the key of C might sound or "feel" somewhat different (besides being in a different pitch) to a listener if it is transposed to the key of A.
*In addition, since many composers often utilized the piano while composing, the key chosen can possibly have an effect over the composing. This is because the physical fingering is different for each key, which may lend itself to choosing to play and thus eventually write certain notes or chord progressions compared to others, or this may be done on purpose to make the fingering more efficient if the final piece is intended for piano.
*In music that does not use [[equal temperament]], chords played in different keys are qualitatively different.