In this group of instruments the sound is produced by the player buzzing his or her lips inside a mouthpiece. The mouthpiece is a metal cup whose shape varies according to the type of brass instrument and it is an essential accessory of all brass instruments. The player’s buzzing lips set in motion the air inside the instrument. You can try and buzz your own lips now – it’s like blowing a raspberry! Even without the use of a mouthpiece you can produce one or two notes!
All modern brass instruments consist of the mouthpiece receiver, or mouthpipe, which is the opening at one end of the instrument tubing where the mouthpiece is inserted, a middle section where the valves or a slide are usually found, and the last part of the instrument which is very flared and is called the bell.
When talking about brass instruments there are two terms you will notice: cylindrical and conical. These describe inside shape of the tubing of brass instruments. When a tube retains the same width from beginning to the end we can describe it as cylindrical. When it widens, we can describe it as conical. Although no brass instrument is cylindrical throughout since at the bell section there is a flare, most brasses are either predominantly cylindrical or predominantly conical. This characteristic determines the sound qualities of brass instruments. This is why trumpets or trombones that are predominantly cylindrical sound brassier than cornets or horns which sound mellower!
Brass instruments would have available a limited number of notes that could be played if it was not for their valves! Valves are means that add certain tubing to the instruments so that more notes can be played on them.
In piston valves there is a piston that moves up-and-down within a cylinder, which engages and disengages the additional tubing. Can you imagine which was the source of inspiration for the development and usage of the piston valve on brass instruments in the beginning of the nineteenth century? The steam engine! In steam engines piston valves were used to pump steam, water, or air. And some ingenious person thought that this would be quite useful for musical instruments. And he was so right!
In rotary valves there is a rotor which turns and allows the air to go through the additional tubing.
In most modern brass instruments a strange device can be used. It is called a mute and it is used by the player so as to alter the sound of the instrument. The modern mutes can be found in a variety of shapes. They are inserted in the instrument’s bell and the sound becomes softer. Their shape depends on the instrument for which they are made. Can you imagine a tuba mute? It is almost gigantic compared to a tiny trumpet mute! It can make even such an enormous instruments like the tuba to produce a warmer and silkier sound. Even toilet plungers have been used by jazz trombonists to create that cool ‘wah-wah’ sound.