There are thousands of types of wind instruments in the world, most of which can be classified as either woodwind or brass instruments.
Although they all operate based on a relatively simple principle, wind instruments vary greatly in the sounds they are able to produce.
While certain instruments remain more popular than others, all of them offer unique, complex sounds that are very difficult to replicate. No doubt, on every quality Keyboard you will find a large bank of Instruments from which to select. You will be hard pressed to find one however which can replicate the unique sound which can be made by an individual set of lips, holding a unique embrouchure, blowing with a certain force, fingering a specific run of notes on a wind instrument. You know, just the way that John Coltrane does it..?
Despite the huge number of different wind instruments in existence, all of them function based on the same principle, regardless of their size, shape, construction and region of origin.
All wind instruments produce tones through a column of air that vibrates throughout their bodies. The player blows into a resonator through a mouthpiece, typically at the end of some sort of tube. This mouthpiece is typically a brass bowl or a wooden reed, although other alternatives exist. The length of the tube determines the pitch of the instrument.
In order to be able to produce more than one note, the instrument must allow the player to manually adjust the effective length of the tube. For brass instruments, this is typically achieved through the use of valves. When a player presses a valve, the path the player's air must take changes in length, causing a different tone to be produced. Trombones allow players to adjust the length of the horn merely by pulling back or pushing back a slide, thus changing the pitch.
Instruments from the Woodwind family typically feature keys instead of valves. Each key closes a hole on the body of the instrument. Rather than physically adjusting the resonator as brass instruments do, this changes the length of the column of air the player produces. By covering a hole, the player forces to air to escape through a different area of the instrument, altering the frequency at which it resonates. This explains the need for the many tone holes on a Saxophone.
Many woodwind instruments also feature a bell at one end. This is partly to amplify the tone produced by the instrument, but the bell is also used to provide different notes with more consistent tones. The following are several other examples of wind instruments: