The word cello is actually just an abbreviation of violoncello, an italian word meaning "little violone". A violone was an instrument common in the 17th and 18th century which evolved into today's double bass. The cello is the tenor voice in the string section. It can play an octave lower than the viola and as with the other strings, the cello section sits two to a desk. There are usually between eight and twelve cellos in a symphony orchestra.
Perhaps more than any instrument the cello sound can create a melancholy mood. It’s deep tenor voice can be further enhanced by a broad vibrato which on other instruments might sound ridiculous. With its particularly wide range and powerful sound it can one minute be playing a bass line and the next a melody that is high enough for the rest of the orchestra to move underneath. Another of its useful qualities is its clarity of attack, which enables it to play crisp architectural shapes and driving rhythmic patterns and as such it makes the cello a key component of the orchestra’s ‘engine room’.
The Cello has four strings, tuned in 5ths to C, G, D and A. The lower strings have a richer, darker sound and to exploit this it is quite common for composers to write that a particular phrase should be played on a particular string. By writing Sul C (on the C) or Sul G above the music the player will continue playing on the low C or G string when they would otherwise have moved up onto one of the higher strings. The composer should know that one should not write Sul C more than one and a half octaves above the open string.
Most cello music will be written in the bass clef and occasionally moves into tenor clef (shown centre above) as the music gets higher. When the music is very high the treble clef is used. Composers need to know that players do not like to change clefs too often and so will only want to go into a higher clef if the music is going to stay up high for a while. Changing back again presents similar problems and cello players will often mention that they do not like to read low notes in tenor clef - of course they can do it, but as a composer, you will always want to minimise anything that players may find distracting. Exact guidelines are difficult to give without going into a lot of detail, so the best thing to do is to show your music to a player and ask them to explain.
Like all the string section the cello is played by drawing the bow across the strings (marked arco in the parts) or by plucking the strings with the fingers (marked Pizzicato).
Photograph courtesy of Bishop Strings