Comes, maybe, from bebopper Kenny Clarke "dropping bombs" - a stark downbeat on the kick drum. In funk, "on the one" standardized bop's out-of-nowhere (compared to swing music) bomb onto the first beat of each measure. It was revolutionary; pop music of the era (the 60s) was all about backbeat - energy on the second and fourth beats. James Brown's songs would soon highlight more of a sixteenth-note pulse - pop had been based on eighth-notes, except for exotica (Let's mambo!) novelties.