Bandas usually have a strong percussion. The percussionists generally provide the accents and do not usually play all the time or keep a 'groove'. Often the percussionists will enter only when the singer is not singing, such as in an instrumental chorus. The groove is mostly provided by the sousaphone (or bass guitar in a few recordings) playing the bass line, and the alto horns playing sharp upbeats. Typically when a banda plays a cumbia, the alto horn players switch to Latin percussion instruments such as timbales, maracas, cowbell, congas, bongos and guiro.