In terms of function, consider a Fender Jazz. It has two single coil pickups, just like an Alembic Series bass. Admittedly, the pickups are different in construction, tone, and aperture, but they are still single coils.
On the Jazz, there is no hum when both pickups are on at equal volume levels. On the other hand, if you run either pickup by itself or a significant mis-match in volume levels, then some hum can be introduced. This is because the two pickups act as humcancellers for each other.
In the Alembic Series circuit, the dummy humcanceller is brought into the circuit for both of the actual pickups. There are trim pots to balance the dummy against each of the live pickups individually so that there is no hum with any combination.