Introduction
Idiophones
Membranophones
Chordophones
Aerophones
Electrophones

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Introduction

Most general introductions to the percussion section start off by making a distinction between the tuned and untuned percussion instruments.  The tuned or pitched percussion includes the harp, the timpani and keyboard instruments such as the xylophone and the glockenspiel.  Untuned percussion instruments include the snare drum, the bass drum and the triangle.  This distinction makes a lot of sense to composers, who need to know which instruments can be sounded regardless of the chord being played by the rest of the ensemble and which cannot.  Seen from the percussionist’s point of view, however, the distinction can be less than useful. 

Instead, percussionists tend to follow the classification system first suggested by Sachs and developed further by Brindle [Curt Sachs The History of Musical Instruments (Norton, New York, 1940).  See also Reginald Smith Brindle Contemporary Percussion (Oxford University Press, London, 1970)].  This system divides percussion instruments into five categories according to how the sound is produced.   These categories are idiophones, membranophones, chordophones, aerophones and electrophones.  These can then be further subdivided into the more commonly recognized tuned and untuned categories.

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Idiophones

Idiophones are percussion instruments that produce sounds though the vibration of their entire body, usually after being struck, although some are shaken instead.  Tuned idiophones include the marimba, the bells and keyboard percussion instruments such as the xylophone, while untuned idiophones include the triangle, wood block, and the castanets.

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Membranophones

Often simply called drums, membranophones produce sounds through the vibration of a membrane (usually made of animal skin or plastic) stretched across a shell or bowl.  The most well known tuned membranophone is the timpani or kettledrum.  Untuned membranophones include the bass drum, snare drum, bongos and tom toms.

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Chordophones

The sound of a chordophone comes from a vibrating string stretched over or through a resonating chamber that helps amplify the sound.  All chordophones are tuned.  Strictly speaking, the piano and harpsichord are chordophones, although they are more commonly regarded as keyboard instruments. Therefore, they do not figure prominently in the wind band percussion section.

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Aerophones

Aerophones are wind instruments which, while they do not produce specific pitches, nevertheless depend on the vibration of a (usually) enclosed air column.   They include sirens, whistles and bull roarers. 

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Electrophones

This is the electronic percussion.  This category includes digital drum sets capable of producing unusual and unique percussion effects through the use of amplifiers, mixers and filters.  The merging of computer technology and electronics has also made it possible for such equipment to generate almost all of the sounds produced by the more traditional percussion instruments.