Four Main Categories of Instruments

By Nancy Hayden
Most brass instruments use valves to change notes.

Most musical instruments fall into one of four groups, all of which are represented in an orchestra. Woodwind, brass, stringed and percussion are the four types and each category contains an array of varied examples. The sounds and notes created by the different types of instruments are often combined by skilled orchestras to create wide-ranging musical performances.

Stringed Instruments

Generally, stringed instruments have a wooden body with a hollow center and are strung with strands of nylon, steel or gut. When the strings are plucked with fingers or a bow is pulled across them they vibrate and the sound is amplified within the body of the instrument. In an orchestra, stringed instruments include violins, violas, cellos and the double bass. Others include guitars, sitars and banjos.

Woodwind Instruments

Woodwind instruments are hollow cylindrical pipes made out of wood, plastic or metal. A mouthpiece at one end typically contains a single or double strip of thin wood -- a reed -- which vibrates when air is blown across it. Sound is produced through an opening at the other end. Musicians cover holes located along the instrument with fingers or keys to create specific notes. Woodwind instruments include the oboe, clarinet, bassoon, piccolo and flute.

Brass Instruments

Brass instruments are long hollow brass pipes with a bell-shaped opening at one end through which sound is produced. These pipes are curved and bent into various shapes to make them easier to hold and play. Brass instruments also work by blowing into a mouthpiece and most have small valves which can be pressed down to create different notes. Brass instruments include trumpets, tubas, trombones and French horns.

Percussion Instruments

Percussion instruments comprise a wide-ranging category including any instrument that has to be struck, shaken or scraped to produce a sound, such as drums, cymbals, chimes bells, maracas and xylophones to name but a few. Pianos also classified as percussion because pressing the keys makes small hammers strike tightened strings to produce notes. Percussion instruments in orchestral and other settings are typically used to help keep rhythm.