The surdo is a large cylindrical bass drum, one of the main instruments of Brazilian samba and of the batucada carnival percussion ensembles. It is carried in front of the body on a strap and played with a single soft-headed mallet, while the other hand often mutes the head, controlling the duration of the sound.
The deep, powerful, low sound of the surdo sets the basic rhythmic pulse of the whole ensemble, which is why it is often called the “heartbeat of samba.” Usually a large ensemble uses several surdos of different size and pitch, which, alternating, create the characteristic springy “step” of samba. It is the surdo that unites dozens, and sometimes hundreds, of musicians into a single rhythmic organism during the Brazilian carnival — one of the largest and loudest festivals on the planet.
