Timpani

Very large bowl-shaped drums made of copper or brass. Most often used in orchestras and symphonies, this drumA hollow cylindrical shell of any size that has a head stretched over one or both ends and is b... has a foot pedal that is attached to the head mechanism which changes the tension, and therefore pitch, of the drum. TimpaniVery large bowl-shaped drums made of copper or brass. Most often used in orchestras and symphon... were the first percussion instruments to be used by classical music composers. 

timps