A C cornet is a fairly uncommon type of musical instrument. It is one type of cornet, a brass instrument similar to a trumpet, but with some design and sound differences. Unlike other types of cornets, it plays at the concert pitch. More common types of cornets include B flat and E flat cornets. A C cornet is generally only used when the cornet player is practicing a piece of concert-tuned music with a concert-tuned instrument.
Usually, when a cornet needs to play at concert pitch, the music is transposed for the type of cornet. It is not usual for a cornet to play at concert pitch on its own, but a C cornet can be convenient for a player who primarily plays with other concert-tuned instruments like the piano. Generally, music is rewritten to account for the change between the concert key and the key the instrument plays. A skilled cornet player can often mentally transpose concert music into the correct notes for his instrument. This is a common skill for musicians who play transposing instruments of many types, including saxophones, trumpets, and clarinets.
Instruments that are not in concert pitch are called transposing instruments. These instruments are named by the note that the instrument sounds when it plays the note written as C on that instrument. A C cornet would play a concert C when playing a C from notation, but a B flat cornet would play a B flat instead. Likewise, an E flat cornet would sound a concert E flat when playing the C written on music for that instrument. Playing on a concert C cornet eliminates the need for transposing cornet music in a group that frequently uses music written in concert pitch.
B flat and E flat are more common types of cornets than the C cornet. Most commonly found in military bands, B flat is the most widely used type of cornet. The E flat cornet is often called the soprano cornet, and is more popular in orchestral music.
Though cornets and trumpets often play the same parts, these instruments do have different timbre qualities. The cornet is generally considered to have a warmer tone than the trumpet, and it can be easier to play during fast moving passages. Differences between the sound qualities of trumpets and cornets are caused by the shape of the inner parts of the instrument. The cornet has a conical bore, instead of a cylindrical one like the trumpet has. This essentially means that the pipes that make the cornet sound gradually taper throughout the instrument, while a trumpet has pipes that remain the same width throughout the instrument.