These are percussion instruments. Sound is produced by a stretched membrane, such as a drum. Membranophonic instruments act as skin-vibrators because they produce sound-waves by vibrations of a stretched skin or membrane when struck, plucked, or stroked. A hollow vessel is covered with a membrane that generates beats when struck. Percussion instruments can be classified by modes of playing:

• played by hand like mridangam;
• played using sticks like nagara;
• played partly by hand and partly by stick-like tavil;
• self struck like damaru;
• and where one side is struck and the other side stroked like a perumal madu drum.