A musical Instrument consisting of a membrane stretched over a frame and beaten with hands or sticks. Drums are known in every culture and therefore every conceivable variation is known.
Drums may be tuned or untuned and may be fixed pitch or variable. The simplest drums are untuned fixed pitch which are used for rhythm only. More sophisticated drums have mechanisms for altering the tension on the head (membrane) and therefore altering the pitch of the drum. This may be as simple as cords which can be tightened by the hand or like the Timpani where pedals are used to change the pitch.
Many drums are equipped with adjustable rims which can be used to tune the drum to a particular pitch.
A collection of drums used together is usually called a drum kit and may comprise other percussion instruments as well as drums - cymbals, cowbells, washboards and 'special effects' such as duck calls or car horns.
The Bodhran is a simple drum from Ireland used to accompany Traditional Music and can be played with great articulation and expression in the right hands. All too often it is simply thumped out of time.
For some reason, African drums - particularly the Djembe have become popular in Folk Music and equally unpopular in Sessions . Drums are generally unpopular for the reason that they fall into the category of instruments which appear deceptively easy to play but in fact require great skill to play properly.