The percussion is calibrated not to overwhelm, but sometimes it can barely help itself.
Any explanation of bomba needs to mention the dancers. There is a subset of drum in this mass drumming that responds particularly to the observed movements of dancers. When an album removes the dancers, the experience becomes a series of reflections between voice and drum and voice and voice and drum and drum. The drumming on Agua del Sol is heavy thunder, the male-female call-and-response of Hijos de Agüeybaná's voices is fleet on top, a more conventional and receptive sound.
The drums are so low and dense in spite of the praise in the booklet. This drumming brings the Puerto Rican community together and provides mental relief to the slaves who pioneered it, though it seems to exist beyond that kind of judgement -- it is itself, and not attached to the brighter surface world of communities and friendship and historical approval. The group aims for balance between the elements, voice and drum, with Cuban piano and saxophone to add pizazz, and the lodestone percussion is calibrated not to overwhelm, but sometimes it can barely help itself.