The bass drum (or “rock drum”) provides a continuous soundtrack that changes with rhythm. The bass drum is the drum type with the lowest pitch, providing either a basic beat or a timing factor with basic pulse patterns. Some drummers can use two or more bass drums, and it is possible to use a double pedal with a bass drum.
The bass drum is an important technique in heavy metal music. Using the double bass drum pedal allows the drummer to play single bass drums like a bass drum, saving space in the recording area and reducing time / effort during installation & transport.