It's actually the same as guitar. Pickups towards the neck will be fatter and towards the bridge will be growlier. The catch is although everyone hates middle pickups, the P bass is the most legendary middle pickup of all time! It's harder to parse what bass pickups do because the bass designs are limited with no real universal designs for experimenting. There are also single coils and humbuckers. Both can growl but hums will be fatter.