In almost every style of music, percussion plays a pivotal role. In military marching bands and pipes and drums, it is the beat of the bass drum that keeps the soldiers in step and at a regular speed, and it is the snare that provides that crisp, decisive air to the tune of a regiment. In classic jazz, one almost immediately thinks of the distinctive rhythm of the hi-hats or the ride cymbal when the word-swing is spoken. In more recent popular-music culture, it is almost impossible to name three or four rock, hip-hop, rap, funk or even soul charts or songs that do not have some sort of percussive beat keeping the tune in time.