timpani

Tuned drums descended from medieval nakers (from Arabic naqqara), with a single head of skin stretched over a hemisphere, usually of copper. They produce notes of definite pitch that can be altered by turning screws at the rim of the ‘kettle’, thus tightening or relaxing the skin. A mechanical device now widely used allows the player to increase or relax the tension (raise or lower the pitch) by means of a pedal. A variety of sticks covered with different materials can be used to produce a harder or softer tone.

Originally used in pairs tuned to the tonic and dominant of the key, timpanis began to increase in number in an orchestra. Mechanisms introduced during the 19th century allowed pitch changes to be made during a performance. A normal symphony orchestra will have up to five timpani, ranging in pitch from about B1 to G3. Sometimes greater numbers are required; Hector Berlioz's massive Requieum Grande Messe des Morts/High Mass of the Dead (1837) needs at least 19 timpani, even using modern pedals.