The surdo is a large bass drum commonly used in Brazilian music, especially in styles like samba and pagode. It provides a deep, resonant sound that helps keep the rhythm for dancers and musicians alike. The surdo is typically played with a mallet and can vary in size, with larger drums producing lower tones. In a samba ensemble, the surdo often plays a crucial role, marking the beat and driving the energy of the performance. Its rhythmic patterns are essential for creating the lively atmosphere found in Brazilian carnivals and celebrations, making it a beloved instrument in the country's rich musical heritage.