percussion instrument

Musical instrument played by being struck with the hand or a beater, crashed, shaken, or scraped. Percussion instruments can be divided into those that can be tuned to produce a sound of definite pitch, such as the timpani, tubular bells, glockenspiel, xylophone, and piano, and those of indefinite pitch, including the bass drum, tambourine, triangle, cymbals, castanets, and gong.

The timpano is a large hemispherical bowl of metal with a membrane stretched across the rim, affixed and tuned by screwtaps or with a pedal mechanism; tubular or orchestral bells are vertically suspended on a frame and struck at the top end with mallets. These instruments were often used by Witold Lutosławski in his orchestral works; the glockenspiel is a small keyboard of aluminium alloy keys played with small beaters; the xylophone has hardwood, rather than metal, bars, and is played using hard-headed beaters to give a distinctive ‘pop’ to the sound.

The snare drum is a shallow double-sided drum on the underside of which gut coils or metal springs are secured by a clamp, and which rattle against the underside when the drum is beaten, while the bass drum produces the loudest sound (unpitched) in the orchestra; the tambourine has a wooden hoop with a membrane stretched across it, and has metal discs suspended in the rim to make a jangling sound; a triangle is formed from a suspended triangular-shaped steel bar, played by striking it with a separate bar of steel – the sound produced can be clearly perceived even when played against a full orchestra; cymbals are two brass dishes struck together; castanets are two hollow shells of wood struck together; and the gong is a suspended disc of metal struck with a soft hammer.