Timpani, also called kettledrums, is a type of tuned percussion instrument that consist of a calfskin or synthetic membrane stretched over a large bowl traditionally made of copper. This drumhead is struck with a specialized mallet or other object, including even the fingers, according to the desired timbre. The timbre also differs slightly according to whether the drumhead is struck in the center or near the edges. Until the late nineteenth century timpani were tuned during performances, a slow and tedious process, but most modern timpani has foot pedals that allow high speed and precise tuning.
A standard set of timpani consists of four or five drums of varying diameters, ranging from about 58 to 81 centimeters, each with a different range of pitches. This is sufficient for most orchestral music.
Early versions of timpani have been in use since ancient times. Modern timpani evolved from military drums to become a standard part of the orchestra by the latter part of the 18th century. Today it is also used in some other types of music, including concert bands, marching bands and some popular music.