Timpani,
or kettledrums, are also tuned percussion instruments. They can play only
a few notes. The notes are changed by pressing a pedal. Most bands and orchestras
will have at least two timpani, and as many as four or five so that more
notes can be played. The small timpani play higher notes and the larger
timpani play lower notes. Timpani are played with special mallets, usually
wrapped in felt. Information provided by: http://www.hypermusic.ca