The surdo is a two-skin drum used in particular in samba. Cylindrical in shape, it is made from a wooden or metal drum 45 to 70 cm high and about 40 to 65 cm in diameter. The skins are of animal or synthetic origin, single or "double" (covered). The main role of the surdo is to mark the second stage and, to a lesser extent, the first stage. It is played with a mallet and the hand, and in some cases with two mallets. It can also be found in frevo and other traditional music groups in the Brazilian Northeast, where it takes on the role of the bass drum in European brass bands.