BRASS INSTRUMENTS

Brass instruments are in fact mostly made of brass, and consist of a long pipe that is usually coiled and has no holes. The player blows into a mouthpiece at one end of the pipe, the vibration of the lips setting the air column vibrating throughout the tube. The force of the lips varies to make the vibrating column divide into two halves, three thirds, and so on. This gives an ascending series of notes called harmonics. Opening extra lengths of tubing then gives other notes that are not in this harmonic series.


LOW PRESURE
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With low lip pressure, the air column vibrates in two halves and each half gives the note middle C. The length of the tube is therefore twice as long as a woodwind instrument sounding the same note

 

INCREASED PRESSURE
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Raising the lip pressure makes the air column vibrate in three thirds. Each vibrating section is two-thirds the length of the previous section, raising the pitch of the note to G.

 

INCREASED LENGTH
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To play an E, which is not in the harmonic series, the player keeps the air vibrating in three thirds and increases the total length of the tube. Each vibrating section becomes four-fifths the length for middle C.

 


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THE TROMBONE
The trombone has a section of tubing called a slide that can be moved in and out. The player pushes out the slide to lengthen the vibrating air column and produce notes that are not in the harmonic series.

 

TrumpetTHE TRUMPET
The trumpet has three pistons that are pushed down to open extra sections of tubing and play notes that are not in the harmonic series. Up to six different notes are obtained by using different combinations of the three pistons.

 

HOW VALVES WORK
On instruments such as the trumpet and tuba, each valve has a loop of tubing attached to it. Normally, the spring pushes against the piston, keeping the valve closed and shutting off the loop. But when the piston is depressed, the air column is diverted through the loop.
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NOW LEARN ABOUT WOODWIND INSTRUMENTS