Cornets are usually made of brass or other metal, and usually silver-plated or lacquered. Today, cornets are played in concert, military and marching bands. The cornet often plays the same music as the trumpet, although there is sometimes a separate cornet part.
On a cornet, the sound is made by the buzzing the player's lips. The mouthpiece helps the sound become clearer. The rest of the cornet makes the sound louder. Any fingering on the cornet can make five or more different notes so you need to have a good ear for music to know if you are playing the right note. The sound of the cornet is more mellow than the sound of the trumpet.
Cornets used to be the main brass instruments in concert bands, now they have been replaced for the most part by trumpets. In older concert band arrangements, especially transcriptions of concert music, there would be five parts, three cornet and two trumpet. The cornets were the main parts, often with a special solo cornet part, and the two trumpet parts would be taken from the orchestral trumpet parts. Today you often see this reversed, or in most arrangements there are now three trumpet parts as the standard instrumentation.
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