The drum is a member of the percussion group, 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.
Most drums are considered “untuned instruments”, however many modern musicians are beginning to tune drums to songs. A few such as timpani are always tuned to a certain pitch. Often, several drums are arranged together to create a drum set that can be played by one musician with all four limbs. Several factors determine the sound a drum produces, including the type of shell the drum has, the type of drumheads it has, and the tension of the drumheads. Different drum sounds have different uses in music. For example, a jazz drummer may want drums that sound crisp, clean, and a little on the soft side, whereas a rock and roll drummer may prefer drums that sound loud and deep. Because these drummers want different sounds, their drums will be constructed differently. The drumhead has the most effect on how a drum sounds. Each type of drumhead serves its own musical purpose and has its own unique sound. Thicker drumheads are lower-pitched and can be very loud. Drumheads with a white plastic coating on them muffle the overtones of the drumhead slightly, producing a less diverse pitch. Drumheads with central silver or black dots tend to muffle the overtones even more.
The second biggest factor affecting the sound produced by a drum is the tension at which the drumhead is held against the shell of the drum. When the hoop is placed around the drumhead and shell and tightened down with bolts, the tension of the head can be adjusted. When the tension is increased, the amplitude of the sound is reduced and the frequency is increased, making the pitch higher and the volume lower. The type of shell also affects the sound of a drum.
Because the vibrations resonate in the shell of the drum, the shell can be used to increase the volume and to manipulate the type of sound produced. The larger the diameter of the shell, the lower the pitch of the drum will be.