Drum

A drum is a musical instrument in the percussion family, technically classified as a membranophone. Drums consist of at least one membrane, called a "drumhead" or "drum skin", that is stretched over a shell and struck, either directly with parts of a player's body, or with some sort of implement such as a drumstick, to produce sound. Drums are the world's oldest and most ubiquitous musical instruments, and the basic design has remained virtually unchanged for thousands of years.

The shell almost invariably has a circular opening over which the drumhead is stretched, but the shape of the remainder of the shell varies widely. In the western musical tradition, the most usual shape is a cylinder, although timpani, for example, use bowl-shaped shells. Other shapes include a frame design (tar), truncated cones (bongo drums), and joined truncated cones (talking drum).

Drums with cylindrical shells can be open at one end (as is the case with timbales), or can have two drum heads. Single-headed drums normally consist of a skin or other membrane, called a head, which is stretched over an enclosed space, or over one of the ends of a hollow vessel. Drums with two heads covering both ends of a cylindrical shell often have a small hole somewhat halfway between the two drumheads; the shell forms a resonating chamber for the resulting sound. Exceptions include the African slit drum, made from a hollowed-out tree trunk, and the Caribbean steel drum, made from a metal barrel. Drums with two heads can also have a set of wires, called snares, held across the bottom head, top head, or both heads, hence the name snare drum.