What In The World Are “Transposing Musical Instruments”?
When is a C not a C? It’s not a riddle or a trick question. It’s
a musical principle. The answer is: a C is not a C when you’re
playing a transposing musical instrument. And it’s not the instrument
that transposes, unfortunatly — some arranger or the player
himself must do that.
To understand what this means, you first have to understand the
definition of concert pitch. Pitch, of course, refers to the
frequency of sound. Concert pitch is the universally agreed upon
definition of the pitch of middle C (and subsequently, every
other note in an octave). From the dawn of written music to the
present day, no matter where on earth you are, middle C always
sounds the same. In other words, every musician in the world
understands and interprets middle C in the same way. This is the
simple definition of concert pitch.
Many instruments, therefore, are manufactured to concert pitch.
This means that when multiple musicians read “C” (or any other
note on a scale) on a musical score, they produce identical
sounds. Instruments that are manufactured in concert pitch
include the piano, some brass instrumnets such as the trombone
and baritone, some woodwinds such as the flute, oboe, and
bassoon.
Many other instruments are not made to produce concert pitch
sounds. These are referred to as transposing instruments. Many
woodwind instruments and some brass fall into this category. When
a transposing instrument player reads and plays “C” in a musical
score, it sounds different from a “C” played by a non-transposing
instrument.
Therefore, music that is written for a band consisting of both
transposing and non-transposing instruments must be adapted for
individual types of instruments. A typical marching band, for
example, may have the same score of music transposed into two,
three or more different keys.
The clarinet is an excellent example of this. It is a transposing
instrument, typically manufactured in B flat. If a B flat
clarinet and a piano played a “C” at the same time, the sounds
produced would not be the same. In order for a B flat clarinet to
play a note that matches a piano playing a “C,” it would have to
play one whole step higher. In other words, it would have to play
a “D.”
What if the two instruments had to play a song together? Music
for the piano would be written at concert pitch. The same music
would have to be transposed one key higher so that the clarinet
would produce the same sound. Though the two songs appear to be
in different keys, the sounds that each instrument would produce
will match in pitch.
Bb instruments include the Bb clarinet, the Bb bass clarinet, the
Bb tenor sax, the Bb trumpet. Music for these instruments are
written in a key which is a whole step higher than concert pitch.
Eb instruments include the Eb clarinet, the Eb alto clarinet, the
Eb alto sax, the Eb bariton sax, and the Eb alto horn. Music for
this group of instruments needs to be written a minor 3rd lower
than concert pitch.
F instruments include the french horn and the English horn. Music
for these instruments must be written in a key that is a perfect
4th lower than concert pitch.
It sounds complicated. You may even ask: why not just manufacture
the clarinet (or other transposing instruments) in concert pitch?
Though it seems this would solve some problems, there are good
reasons that certain instruments produce other pitches. The B
flat clarinet is preferred because it produces a cleaner, more
pleasant sound than a C soprano (concert pitch) clarinet. In
fact, the same is true of many transposing instruments. So while
using transposing instruments make more work for the composer, in
the end it’s all about the product. Serious musicians are known
for their keen sense of hearing. Since only the best quality
sound will do for them, composers will keep writing scores with
both types of instruments in mind.