Large Brazilian double-headed bass drum, often carried in parades. Generally played with a mallet in one hand while the other hand strikes the head directly, or sometimes with 2 mallets. Can also be fitted with legs for static performances.

Surdos come in various sizes, from 14" to 24", and are made with a metal or thin wood shell and originally had goat skin heads. Plastic heads are common now and many groups from Bahia now put a layer of naugahide or split cowhide over the plastic, producing a more low end sound.