1.1 Wind instruments: some basics  (Page 35/3)

Introduction

The brass and woodwind sections of the orchestra - all the instruments that one blows into to produce a sound - are called the wind instruments , or winds . The technical term for these instruments is aerophones . There are several basic terms that you need to know in order to discuss wind instruments and the playing of wind instruments. Some of the most common are introduced here.

Mouthpieces: getting the sound started

In most wind instruments, the air is blown into the instrument at or near one end of the tube and exits at the other end. The place where the air is blown in is the mouthpiece . It is often detachable from the instrument, allowing the player to use the same mouthpiece on different instruments, or different mouthpieces on the same instrument, as needed. The sound vibration usually begins at the mouthpiece, and wind instruments are classified by mouthpiece types.

Reed instruments use small, rectangular pieces of reed plants (the pieces are called simply reeds ) in their mouthpieces. The reed vibrates very quickly, opening and closing the end of the instrument like an incredibly fast valve. When the rapid puffs of air coming through this "valve" cause a sympathetic vibration of the air in the body of the instrument, the result is a woodwind sound. When they don't, the result is a squeak familiar to all reed players. In a single-reed instrument, the reed vibrates against the mouthpiece. In a double-reed instrument, two pieces of reed vibrate against each other.

In flute-type instruments, a narrow airstream vibrates quickly over and under a sharp edge. (Please see Flutes for more about how this type of mouthpiece works.)

In brass instruments, the players lips vibrate against each other and against the rim of a cup mouthpiece . Note that an instrument is classified as brass not because it is made of metal, but because it has this type of mouthpiece, which relies on vibrating lips.

In all of these cases, the mouthpiece vibration is the original vibration that the rest of the instrument picks up, magnifies, and turns into a pretty sound.

Bells and bores: the shape of the instrument

Most wind instruments are vaguely tube-shaped, because a long, thin column of air is a good place to set up a standing waves of air . The properties of this standing sound wave inside the instrument are what give the sound its pitch , its dynamic level (loudness or softness), its harmonics , and its timbre (color). So an instrument's sound depends mostly on the size and shape of the tube that the air moves through.

The air enters the instrument at the mouthpiece (see above ). After a length of tube which widens gradually or hardly at all, the other end of the instrument often flares abruptly. This flared section at the end of the instrument is the bell . The bell can be quite large and gradual, as in a French horn , or small and abrupt, as in a trumpet, or even narrowing, as in a bassoon.