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The Brass section is usually composed by four Horns, two or three Trumpets, three Trombones and a Tuba. The number of musicians of each instrument can vary, and in some huge instrumentations can be formed by eight Horns, five Trumpets, four Trombones and two Tubas. Some instrument of the family can also be played or double, like the Tenor Horns in the Horn section, the Cornets in the Trumpet family and the Bass Trombone in the Trombone section.
This family produce the sound by blowing in a mouthpiece, which produce a sympathetic vibration of air. In order to produce the different pitches, the Brass instrument have slides, valves or keys which are used to change the length of the metal tube. That produces a different harmonic series allowing the player with the lip tension and the air flow s/he do to play the correct note.