Musical Keys - Instruments in A Key

Instruments in A Key

Certain musical instruments are sometimes said to 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 instruments. The most common kind of clarinet, for example, is said to play in the key of B-flat. This means that a scale written in C major in sheet music will actually sound as a B-flat major scale when played on the B-flat clarinet; that is, notes sound a whole tone lower than written. Likewise, the horn, normally in the key of F, sounds notes a perfect fifth lower than written.

Similarly, some instruments may be said to be built in a certain key. For example, a brass instrument built in B-flat will play a fundamental note of B-flat, and will be able to play notes in the harmonic series starting on B-flat without using valves, fingerholes, or slides or otherwise altering the length of the vibrating column of air. An instrument built in a certain key will often, but not always, have its 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: accidentals are difficult or impossible to play.

The highland bagpipes are built in E-flat major, although the music is written in D major.

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

• As noted earlier, certain instruments are said to be 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 clarinettist, for example, it is common to carry two instruments tuned a semitone apart (B-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-flat instrument would be difficult, and to rewrite all the orchestral parts to allow the piece to be played in B-flat major would be an enormous effort. Even so, it is not unheard of for a piece published in B-flat to include notes a semitone (or more) below the range of the common B-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 song that might be in the key of C might sound or "feel" somewhat different (besides being in a different pitch) to an observer 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.