Reggae has a distinctive musical signature that Marley mastered:

• The offbeat — guitar and keyboard accent beats 2 and 4 (the "skank"), creating a laid-back, rolling feel, the opposite of rock's emphasis on 1 and 3
• Deep bass — the bass guitar carries the melody, not just the rhythm. Aston "Family Man" Barrett's bass was as central to Marley's sound as Marley himself
• Slow tempo — reggae usually sits at 60-90 BPM, slower than most pop, for a meditative groove

The style evolved from ska (fast) to rocksteady (smoother) to reggae (the deepest groove).