Tremolo is a
technique used on a
bowed string instrument. The bow is moved back and forth very quickly, producing a "shaking"
effect. Tremolo can be used to achieve a number of different
sounds. If combined with an
accent, a sense of urgency and energy is conveyed. When used more statically, over longer periods of time, the effect is more like a
carpet of
sound.
The Austrian composer Anton Bruckner (1824-96) used tremolo extensively throughout his nine symphonies, making them physically hard to play. It is often better to play a slightly slower tremolo in his works, adding to the feeling of a carpet of sound, and the term "Bruckner tremolo" is sometimes used for a slower, more sluggish tremolo. Contemporary composers also use this effect a lot, and when combined with other techniques, such as sul ponticello, sul tasto, glissando etc., the result can be quite astonishing.